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Sample records for chromatography thin layer

  1. Modern Thin-Layer Chromatography.

    Science.gov (United States)

    Poole, Colin F.; Poole, Salwa K.

    1989-01-01

    Some of the important modern developments of thin-layer chromatography are introduced. Discussed are the theory and instrumentation of thin-layer chromatography including multidimensional and multimodal techniques. Lists 53 references. (CW)

  2. High Performance Thin Layer Chromatography.

    Science.gov (United States)

    Costanzo, Samuel J.

    1984-01-01

    Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

  3. Thin Layer Chromatography (TLC) of Chlorophyll Pigments.

    Science.gov (United States)

    Foote, Jerry

    1984-01-01

    Background information, list of materials needed, procedures used, and discussion of typical results are provided for an experiment on the thin layer chromatography of chlorophyll pigments. The experiment works well in high school, since the chemicals used are the same as those used in paper chromatography of plant pigments. (JN)

  4. Christhin: Quantitative Analysis of Thin Layer Chromatography

    CERN Document Server

    Barchiesi, Maximiliano; Renaudo, Carlos; Rossi, Pablo; Pramparo, María de Carmen; Nepote, Valeria; Grosso, Nelson Ruben; Gayol, María Fernanda

    2012-01-01

    Manual for Christhin 0.1.36 Christhin (Chromatography Riser Thin) is software developed for the quantitative analysis of data obtained from thin-layer chromatographic techniques (TLC). Once installed on your computer, the program is very easy to use, and provides data quickly and accurately. This manual describes the program, and reading should be enough to use it properly.

  5. Rotating-disk thin-layer chromatography

    International Nuclear Information System (INIS)

    Fundamental studies and applications of a new separations technique, rotating-disk thin-layer chromatography (RDTLC), are reported. The studies include evaluation of several packing methods, effects of silica activation on the reproducibility and related efficiencies of the chromatographic systems, and the utility of the instrument with regard to the fractionation of complex mixtures. Reproducibility is found to be excellent if the adsorbent activity is controlled. The technique is most advantageous when used for preparative separations. It is also shown to be useful in the clean-up of complex natural products for subsequent analysis

  6. Thin layer chromatography residue applicator sampler

    Science.gov (United States)

    Nunes, Peter J.; Kelly, Fredrick R.; Haas, Jeffrey S.; Andresen, Brian D.

    2007-07-24

    A thin layer chromatograph residue applicator sampler. The residue applicator sampler provides for rapid analysis of samples containing high explosives, chemical warfare, and other analyses of interest under field conditions. This satisfied the need for a field-deployable, small, hand-held, all-in-one device for efficient sampling, sample dissolution, and sample application to an analytical technique. The residue applicator sampler includes a sampling sponge that is resistant to most chemicals and is fastened via a plastic handle in a hermetically sealed tube containing a known amount of solvent. Upon use, the wetted sponge is removed from the sealed tube and used as a swiping device across an environmental sample. The sponge is then replaced in the hermetically sealed tube where the sample remains contained and dissolved in the solvent. A small pipette tip is removably contained in the hermetically sealed tube. The sponge is removed and placed into the pipette tip where a squeezing-out of the dissolved sample from the sponge into the pipette tip results in a droplet captured in a vial for later instrumental analysis, or applied directly to a thin layer chromatography plate for immediate analysis.

  7. Thin-Layer Chromatography: Four Simple Activities for Undergraduate Students.

    Science.gov (United States)

    Anwar, Jamil; And Others

    1996-01-01

    Presents activities that can be used to introduce thin-layer chromatography at the undergraduate level in relatively less developed countries and that can be performed with very simple and commonly available apparati in high schools and colleges. Activities include thin-layer chromatography with a test-tube, capillary feeder, burette, and rotating…

  8. Thin-Layer and Paper Chromatography.

    Science.gov (United States)

    Sherma, Joseph; Fried, Bernard

    1984-01-01

    Reviews literature on chromatography examining: books, reviews, student experiments; chromatographic systems, techniques, apparatus; detecting and identification of separated zones; preparative chromatography and radiochromatography; and applications related to specific materials (such as acids, alcohols, amino acids, antibiotics, enzymes, dyes,…

  9. Thin-Layer Chromatography: The "Eyes" of the Organic Chemist

    Science.gov (United States)

    Dickson, Hamilton; Kittredge, Kevin W.; Sarquis, Arlyne

    2004-01-01

    Thin-layer chromatography (TLC) methods are successfully used in many areas of research and development such as clinical medicine, forensic chemistry, biochemistry, and pharmaceutical analysis as TLC is relatively inexpensive and has found widespread application as an easy to use, reliable, and quick analytic tool. The usefulness of TLC in organic…

  10. A Thin Layer Chromatography Laboratory Experiment of Medical Importance

    Science.gov (United States)

    Sharma, Loretta; Desai, Ankur; Sharma, Ajit

    2006-01-01

    A thin layer chromatography experiment of medical importance is described. The experiment involves extraction of lipids from simulated amniotic fluid samples followed by separation, detection, and scanning of the lecithin and sphingomyelin bands on TLC plates. The lecithin-to-sphingomyelin ratio is calculated. The clinical significance of this…

  11. 21 CFR 862.2270 - Thin-layer chromatography system for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Thin-layer chromatography system for clinical use... Instruments § 862.2270 Thin-layer chromatography system for clinical use. (a) Identification. A thin-layer... a mixture. The mixture of compounds is absorbed onto a stationary phase or thin layer of...

  12. High performance thin layer chromatography profile of Cassytha filiformis

    Institute of Scientific and Technical Information of China (English)

    Mythili Sathiavelu; Sathiavelu Arunachalam

    2012-01-01

    Objective: To study the phenols, flavonoids, saponin profile of the medicinal plant Cassytha filiformis (C. filiformis) using high performance thin layer chromatography (HPTLC). Methods:The extracts were tested to determine the presence of various phytochmeicals like alkaloids, phenolic compounds, flavonoids, carbohydrates, glycosides, saponins, terpenoids, tannins, fixed oils, fats and protein and aminoacids (Harborne and Harborne, 1998). HPTLC studies were carried out by Harborne and Wagner et al method. Different compositions of the mobile phase for HPTLC analysis were tested in order to obtain high resolution and reproducible peaks. Results: The results of the preliminary phytochemical studies confirm the presence of phenols, alkaloids, carbohydrates, saponins, flavanoids, terpenoids and tannins in the methanolic extracts of C. filiformis. The methanolic extracts of C. filiformis displayed the presence of 13 types of phenolic substances with 13 different Rf values ranging from 0.01 to 0.96. The results illustrated the presence of 9 different types of flavonoides with 9 different Rf values ranging from 0.01 to 0.97. The results of HPTLC analysis of saponins demonstrated the presence of 11 different types of saponins with 11 different Rf values ranging from 0.04 to 0.92. Conclusions: In the present study we observed the phenols, flavonoids, saponin profile of the medicinal plant C. filiformis using high performance thin layer chromatography (HPTLC). Hence it was concluded that the phenolic compounds present in the methonolic extract could be responsible for antioxidant activities. Plant derived antioxidants, especially phenols and flavonoids, have been described to have various properties like anticancer, antiaging and prevention of cardiovascular diseases. Furthur, separation and characterization of the bioactive compound from the plant is to be evaluated and reported in near future.

  13. Comparison of cytotoxicity and thin-layer chromatography methods for detection of mycotoxins.

    OpenAIRE

    Robb, J; Norval, M

    1983-01-01

    Thirty-three standard mycotoxins were assayed by thin-layer chromatography and by cytotoxicity in HEp-2 and Chang cells. Various levels of detection were found. The cytotoxicity test was significantly more sensitive than thin-layer chromatography for the trichothecenes and should be useful for screening extracts from animal feedstuffs for the presence of unknown mycotoxins.

  14. Isolation of Three Components from Spearmint Oil: An Exercise in Column and Thin-Layer Chromatography

    Science.gov (United States)

    Davies, Don R.; Johnson, Todd M.

    2007-01-01

    A simple experiment for undergraduate organic chemistry students to separate a colorless mixture using column chromatography and then monitor the outcome of the separation using thin-layer chromatography (TLC) and infrared spectroscopy(IR) is described. The experiment teaches students the principle and techniques of column and thin-layer…

  15. Normal and Reversed-Phase Thin Layer Chromatography of Green Leaf Extracts

    Science.gov (United States)

    Sjursnes, Birte Johanne; Kvittingen, Lise; Schmid, Rudolf

    2015-01-01

    Introductory experiments of chromatography are often conducted by separating colored samples, such as inks, dyes, and plant extracts, using filter paper, chalk, or thin layer chromatography (TLC) plates with various solvent systems. Many simple experiments have been reported. The relationship between normal chromatography and reversed-phase…

  16. High-performance thin layer chromatography: A powerful analytical technique in pharmaceutical drug discovery

    OpenAIRE

    Attimarad, Mahesh; Ahmed, K. K. Mueen; Aldhubaib, Bandar E.; Harsha, Sree

    2011-01-01

    Analysis of pharmaceutical and natural compounds and newer drugs is commonly used in all the stages of drug discovery and development process. High-performance thin layer chromatography is one of the sophisticated instrumental techniques based on the full capabilities of thin layer chromatography. The advantages of automation, scanning, full optimization, selective detection principle, minimum sample preparation, hyphenation, and so on enable it to be a powerful analytical tool for chromatogr...

  17. Peak broadening in paper chromatography and related techniques : III. Peak broadening in thin-layer chromatography on cellulose powder

    NARCIS (Netherlands)

    Ligny, C.L. de; Remijnse, A.G.

    1968-01-01

    The mechanism of peak broadening in thin-layer chromatography on cellulose powder was investigated by comparing the peak widths obtained in chromatography with those caused only by diffusion in the cellulose powder, for a set of amino acids of widely differing RF values and six kinds of cellulose po

  18. Detection of Phenolic and Flavonoid Compounds Using High Performance Thin Layer Chromatography (HPTLC).

    Science.gov (United States)

    2016-01-01

    High performance thin layer chromatography (HPTLC) is a sophisticated instrumental technique based on the full capabilities of thin layerchromatography. The advantages of automation, scanning, full optimization, selective detection principle, minimum sample preparation,hyphenation, etc., enable it to be a powerful analytical tool for chromatographic information of complex mixtures of inorganic, organic andbiomolecules which are characterized in this chapter. PMID:26939287

  19. Trace analysis of acrylamide by high-performance thin-layer chromatography coupled to mass spectrometry

    OpenAIRE

    Alpmann, Alexander

    2011-01-01

    Planar-chromatography (High-Performance Thin-Layer Chromatography, HPTLC) is a rapid and cost-effective offline separation method. Through advances in the automatization of each step the system reproducibility, from application and development to detection, has been improved. This makes planar-chromatography a highly reliable technique. HPTLC shows a couple of features that make it unique. There is great flexibility concerning application, development and detection that distinguishes HPTLC fr...

  20. Digitally Enhanced Thin-Layer Chromatography: An Inexpensive, New Technique for Qualitative and Quantitative Analysis

    Science.gov (United States)

    Hess, Amber Victoria Irish

    2007-01-01

    A study conducted shows that if digital photography is combined with regular thin-layer chromatography (TLC), it could perform highly improved qualitative analysis as well as make accurate quantitative analysis possible for a much lower cost than commercial equipment. The findings suggest that digitally enhanced TLC (DE-TLC) is low-cost and easy…

  1. A Simple and Inexpensive Capillary Holder for Thin-Layer Chromatography

    Science.gov (United States)

    Pintea, Beniamin-Nicolae V.

    2011-01-01

    Thin-layer chromatography (TLC) is a widely used method of qualitative analysis in organic synthesis, as it uniquely combines low cost, rapidity, simplicity, versatility, small quantities of sample and low detection limits. The simplest and most economical method for the application of samples onto TLC plates is by hand, using glass capillaries.…

  2. Evaluating Mechanisms of Dihydroxylation by Thin-Layer Chromatography: A Microscale Experiment for Organic Chemistry

    Science.gov (United States)

    Burlingham, Benjamin T.; Rettig, Joseph C.

    2008-01-01

    A microscale experiment is presented in which cyclohexene is dihydroxylated under three sets of conditions: epoxidation-hydrolysis, permanganate oxidation, and the Woodward dihydroxylation. The products of the reactions are determined by the use of thin-layer chromatography. Teams of students are presented with proposed mechanisms for each…

  3. Phospholipids, Dietary Supplements, and Chicken Eggs: An Inquiry-Based Exercise Using Thin-Layer Chromatography

    Science.gov (United States)

    Potteiger, Sara E.; Belanger, Julie M.

    2015-01-01

    This inquiry-based experiment is designed for organic or biochemistry undergraduate students to deduce the identity of phospholipids extracted from chicken eggs and dietary supplements. This is achieved using thin-layer chromatography (TLC) data, a series of guided questions of increasing complexity, and provided relative retention factor (Rf)…

  4. Analysis and Identification of Acid-Base Indicator Dyes by Thin-Layer Chromatography

    Science.gov (United States)

    Clark, Daniel D.

    2007-01-01

    Thin-layer chromatography (TLC) is a very simple and effective technique that is used by chemists by different purposes, including the monitoring of the progress of a reaction. TLC can also be easily used for the analysis and identification of various acid-base indicator dyes.

  5. Analysis of Peppermint Leaf and Spearmint Leaf Extracts by Thin-Layer Chromatography

    Science.gov (United States)

    Pelter, Libbie S. W.; Amico, Andrea; Gordon, Natalie; Martin, Chylah; Sandifer, Dessalyn; Pelter, Michael W.

    2008-01-01

    In this inquiry-based activity, the usefulness of thin-layer chromatography (TLC) to visualize the difference between spearmint and peppermint is explored. The experiment may be used in any class where TLC is discussed from high school to college. We have used this activity with science majors in an organic chemistry laboratory, with non-science…

  6. Separation and identification of amino acids from lignite humic acids by thin layer chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Damian, L.; Marutoiu, C.; Niac, G.

    1985-07-01

    Thin layer chromatography with and without temperature gradient was used to identify ten amino acids in the humic acid hydrolysate of Rovinari lignite, using cellulose and volcanic tuff as stationary phases. The acids found were L-leucine, isoleucine, phenylalanine, L-valine, tyrosine, proline, L-alanine, glutamic acid, threonine and L-lysine. 8 references.

  7. Thin-layer chromatography and colorimetric analysis of multi-component explosive mixtures

    Science.gov (United States)

    Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie

    2014-08-26

    A thin-layer chromatography method for detection and identification of common military and peroxide explosives in samples includes the steps of provide a reverse-phase thin-layer chromatography plate; prepare the plate by marking spots on which to deposit the samples by touching the plate with a marker; spot one micro liter of a first standard onto one of the spots, spot one micro liter of a second standard onto another of the spots, and spot samples onto other of spots producing a spotted plate; add eluent to a developing chamber; add the spotted plate to the developing chamber; remove the spotted plate from the developing chamber producing a developed plate; place the developed plate in an ultraviolet light box; add a visualization agent to a dip tank; dip the developed plate in the dip tank and remove the developed plate quickly; and detect explosives by viewing said developed plate.

  8. Regiospecific Analysis of Marine Oil Triacylglycerols Using Boric Acid High-Performance Thin-Layer Chromatography

    OpenAIRE

    ANDO, Yasuhiro; Haba, Yusuke; Takase, Kiwamu; Sakai, Shinya

    2007-01-01

    This paper presents a smaller-sized procedure for regiospecific analysis of triacylglycerols (TAG) using boric acid high-performance thin-layer chromatography (HPTLC). Cod liver/mackerel, bonito head, and seal oils TAG (2mg) were partially hydrolyzed by ethyl magnesium bromide, and resulting 1(3)-and 2-monoacylglycerols (MAG) were isolated by the HPTLC. Fatty acids of the 1(3)-and 2-MAG were analyzed by gas-liquid chromatography (GLC). Positional distributions of fatty acids in TAG observed f...

  9. Characterization of bronzes by abrasive stripping voltammetry and thin layer chromatography

    OpenAIRE

    Komorsky-Lovrić, Šebojka; Horvat, Alka J.M.; Ivanković, Danijela

    2006-01-01

    Corrosion potentials of five samples of bronzes having different compositions and the stripping peak potentials of their main components were determined by abrasive stripping voltammetry. Using thin-layer chromatography in combination with electrochemical dissolution of bronzes in the two electrode sampler, the ions of tin, copper, lead and nickel were detected as the products of electro-oxidation of bronzes. It is shown that the dissolution of tin is preferential at low potential differences...

  10. Comparison between high performance liquid chromatography and high performance thin layer chromatography determination of Diosgenin from fenugreek seeds

    Directory of Open Access Journals (Sweden)

    Dheeraj H Nagore

    2012-01-01

    Full Text Available Background: Fenugreek is used in the treatment of many diseases as reported in Ayurveda. The chemical like Diosgenin is one of the important chemicals of fenugreek. Aim: To develop simple, rapid, accurate methods for estimation of Diosgenin from fenugreek using high performance thin layer chromatography (HPTLC and high performance liquid chromatography (HPLC. Materials and Methods: The two chromatographic methods, HPTLC and HPLC, were developed and compared to quantitative determination of Diosgenin in fenugreek seed extract. For both the analyses, the scanning wavelength was set at 205 nm. The Diosgenin content of seven different extracts collected from different locations was compared by HPLC and HPTLC. Statistical Analysis: The relative standard deviation and correlation coefficient (r2 were calculated by standard Formulae. Results: The comparison was done in HPTLC and HPLC results and all the results are found to be within the limits and showed no significant difference. Conclusion: Both the methods were accurate and specific for the analysis of Diosgenin.

  11. Thin-Layer Chromatography Experiments That Illustrate General Problems in Chromatography.

    Science.gov (United States)

    Lederer, M.; Leipzig-Pagani, E.

    1996-01-01

    Describes experiments that illustrate a number of general principles such as pattern identification, displacement chromatography, and salting-out adsorption, plus an experiment that demonstrates that identification by chromatography alone is impossible. Illustrates that chromatography is still possible with quite simple means, notwithstanding the…

  12. Extraction of oxytetracycline starting from the meats of chickens and identifications by thin layer chromatography

    International Nuclear Information System (INIS)

    Use of antibiotics in the poultry also suspected as one of the cause of the emergence of resistance to antibiotics of some bacteria what causes risks on human health continuation of persistence of the residues in the foodstuffs. We were interested in detected the presence qualitatively of oxytetracyclin in samples of muscle and liver of chicken by the use of the techniques of thin layer chromatography. Although, These results are satisfactory, it is always necessary to prevent the dangers which cause the risks of the residues of oxytetracycline on health. (Author). 20 refs

  13. EVALUATION OF FOOD COLOR CONSUMPTION AND DETERMINING COLOR TYPE BY THIN LAYER CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Fereshteh Farzianpour

    2013-01-01

    Full Text Available The aim of this research was to investigate the role of the social demographic parameters of the people in charge of the facilities producing pastry, poolak (a type of coin-shaped candy and rock candy in the consumption of food colors and to determine color type by thin layer chromatography in Shahr-e-kord city in 2011. This research was an interventional-analytical study and its target population is the people in charge of the facilities producing pastry, poolak and rock candy in Shahr-e-kord city. Social demographic data of the participants were collected using checklists and 720 samples of pastry, poolak and rock candy weighing at least 250 gr were randomly taken over a period of 10 months. With respect to color additives, the samples were analyzed by Thin Layer Chromatography (TLC in four groups: natural colors permitted artificial colors, forbidden artificial colors and without colors. 48.47% contained food color and 6.52% contained forbidden artificial food color. Sunset Yellow was the color the most consumed among the colors used. Regarding the results obtained, there is a high rate of consumption of artificial colors (41.22%, sunset Yellow being the most consumed. Therefore, it is of great importance to raise the awareness and change the attitude of the people in charge in these jobs as well as the consumers with regard to the side effects of artificial colors, which can be done through the mass media and NGOs.

  14. Two-dimensional thin-layer chromatography for the specific detection of hippurate hydrolysis by microorganisms.

    Science.gov (United States)

    Lin, J Y; Chen, K C; Hale, J; Totten, P A; Holmes, K K

    1986-01-01

    Glycine, one of the end products of hippurate hydrolysis by microorganisms, was detected by a rapid, specific technique utilizing two-dimensional thin-layer chromatography. A loopful of growth of each organism from its suitable agar medium was washed, suspended, and incubated with 0.1% sodium hippurate for 30 min at 37 degrees C. The supernatant of the incubated suspension from each organism was then dansylated, and the dansyl derivatives were separated by two-dimensional thin-layer chromatography on polyamide sheets. Glycine, a product of hippurate hydrolysis, was detected under UV light. This technique does not require prolonged incubation and was found to be more specific and reliable than the standard ninhydrin reaction. In addition, it is inexpensive and can be easily conducted in a clinical microbiological reference laboratory. By this method, 100% (22/22) of Campylobacter jejuni and 0% (0/9) of Campylobacter coli reference strains were positive. In addition, 100% (13/13) of group B streptococci, 100% (24/24) of group D streptococci, and 90% (18/20) of Gardenerella vaginalis clinical isolates were positive for hippurate hydrolysis. This method is useful for the identification to the species level of Campylobacter organisms and the biotyping of Gardnerella organisms and for the detection of hippurate hydrolysis by unknown microorganisms. Images PMID:3517036

  15. Rapid identification of α-glucosidase inhibitors from Phlomis tuberosa by Sepbox chromatography and thin-layer chromatography bioautography.

    Directory of Open Access Journals (Sweden)

    Yingbo Yang

    Full Text Available Alpha-glucosidase inhibitors currently form an important basis for developing novel drugs for diabetes treatment. In our preliminary tests, the ethyl acetate fraction of Phlomis tuberosa extracts showed significant α-glucosidase inhibitory activity (IC₅₀ = 100 μg/mL. In the present study, a combined method using Sepbox chromatography and thin-layer chromatography (TLC bioautography was developed to probe α-glucosidase inhibitors further. The ethyl acetate fraction of P. tuberosa extracts was separated into 150 individual subfractions within 20 h using Sepbox chromatography. Then, under the guidance of TLC bioautography, 20 compounds were successfully isolated from these fractions, including four new diterpenoids [14-hydroxyabieta-8,11,13-triene-11-carbaldehyde-18-oic-12-carboxy-13-(1-hydroxy-1-methylethyl-lactone (1, 14-hydroxyabieta-8,11,13-triene-17-oic-12-carboxy-13-(1-hydroxy-1-methylethyl-lactone (2, 14,16-dihydroxyabieta-8,11,13-triene-15,17-dioic acid (3, and phlomisol (15,16-eposy-8,13(16,14-labdatrien-19-ol (4], and 16 known compounds. Activity estimation indicated that 15 compounds showed more potent α-glucosidase inhibitory effects (with IC50 values in the range 0.067-1.203 mM than the positive control, acarbose (IC50 = 3.72 ± 0.113 mM. This is the first report of separation of α-glucosidase inhibitors from P. tuberosa.

  16. Thin layer chromatography coupled to paper spray ionization mass spectrometry for cocaine and its adulterants analysis.

    Science.gov (United States)

    De Carvalho, Thays C; Tosato, Flavia; Souza, Lindamara M; Santos, Heloa; Merlo, Bianca B; Ortiz, Rafael S; Rodrigues, Rayza R T; Filgueiras, Paulo R; França, Hildegardo S; Augusti, Rodinei; Romão, Wanderson; Vaz, Boniek G

    2016-05-01

    Thin layer chromatography (TLC) is a simple and inexpensive type of chromatography that is extensively used in forensic laboratories for drugs of abuse analysis. In this work, TLC is optimized to analyze cocaine and its adulterants (caffeine, benzocaine, lidocaine and phenacetin) in which the sensitivity (visual determination of LOD from 0.5 to 14mgmL(-1)) and the selectivity (from the study of three different eluents: CHCl3:CH3OH:HCOOHglacial (75:20:5v%), (C2H5)2O:CHCl3 (50:50v%) and CH3OH:NH4OH (100:1.5v%)) were evaluated. Aiming to improve these figures of merit, the TLC spots were identified and quantified (linearity with R(2)>0.98) by the paper spray ionization mass spectrometry (PS-MS), reaching now lower LOD values (>1.0μgmL(-1)). The method developed in this work open up perspective of enhancing the reliability of traditional and routine TLC analysis employed in the criminal expertise units. Higher sensitivity, selectivity and rapidity can be provided in forensic reports, besides the possibility of quantitative analysis. Due to the great simplicity, the PS(+)-MS technique can also be coupled directly to other separation techniques such as the paper chromatography and can still be used in analyses of LSD blotter, documents and synthetic drugs. PMID:26970868

  17. Differentiation of coloured inks of inkjet printer cartridges by thin layer chromatography and high performance liquid chromatography.

    Science.gov (United States)

    Poon, N L; Ho, S S H; Li, C K

    2005-01-01

    Document examiners are frequently asked to determine whether or not a colour printout has originated from a particular inkjet printer. The printer can rarely be identified unless some unique defects or irregularities of the printer are present on the printout. However, it is possible to decipher the make and/or model of the printer by comparing the ink-profile of the questioned printout with that of a seized inkjet printer cartridge or from one in a database. This paper presents an overview of a systematic approach to characterising and discriminating the inks of different inkjet printer cartridges using thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC) with multi-wavelength ultra-violet/visible (UV/Vis) detection. Ink samples from 23 different inkjet printer cartridges (including originals and substitutes) of different brands and colour printouts, printed by known printers were examined with newly developed chromatographic methods. Subsequently, a database of the ink-profiles was generated. The methods provide a useful tool for discriminating coloured inks in inkjet printer cartridges of different brands.

  18. Separation of catechins and O-methylated (-)-epigallocatechin gallate using polyamide thin-layer chromatography.

    Science.gov (United States)

    Wang, Kunbo; Chen, Qincao; Lin, Yong; Yu, Shuangshang; Lin, Haiyan; Huang, Jianan; Liu, Zhonghua

    2016-04-01

    Thin-layer chromatography (TLC) method for the separation and quantitative determination of seven related compounds: (+)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3″Me) and (-)-epigallocatechin- 3-O-(4-O-methyl) gallate (EGCG4″Me) has been developed. The above-mentioned seven compounds have been resolved using polyamide TLC plates using a double-development with methanol followed by acetone/acetic acid (2:1, v/v). In addition, separation of the phenolic acids namely gallic acid, chlorogenic acid, and caffeic acid was achieved using the same solvent system. The applicability of the method was checked by screening of extracts of green, black, oolong, white tea and tea cultivars leaves. PMID:26990737

  19. DETERMINING THE CONTENT OF JASMINODIN IN MEI RONGCAPSULE WITH THIN LAYER CHROMATOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective Jasminodin in Mei Rong capsule was determined by the method of thin layer chromatography. Methods The sample jasminodin was extracted with methanol and then the extract was chromatographed on silica gel GF254 plate with chloroform-methanol-water (10:3:1) as mobile phase and the chromatograms were scanned by using Shimadzu CS-930 dual wavelength TLCS in zegzag scanning mode at λs 370nm and λR 250nm.Results Calibration graph was rectilinear between 2.7μg~16.2μg per spot for the jasminodin. Conclusion Satisfatory results were obtained with the average recovery ratio of 99.76% ,RSD 2.27%.

  20. Preliminary phytochemical investigation and thin layer chromatography profiling of sequential extracts of Moringa oleifera pods

    Directory of Open Access Journals (Sweden)

    Veena Sharma

    2013-01-01

    Full Text Available Context: Moringa oleifera Lam (Moringaceae is a highly valued plant, distributed in many countries of the tropics and subtropics. It has an impressive range of medicinal uses with high nutritional value. Aim: The present study, primarily aims to carry out a preliminary phytochemical screening so as to detect the major class of compounds present in M. oleifera and to perform thin layer chromatography (TLC profiling of all sequential extracts. Materials and Methods: Phytochemical analysis was performed by various qualitative methods and TLC profiling was carried out using various solvent system of varying polarity. Results and Conclusions: Qualitative phytochemical analysis reflects the presence of phenolics, triterpenoids, cardiac glycosides, steroid, alkaloids and saponin in the plant extract. TLC profiling of the M. oleifera pods was carried out using sequential extracts of petroleum ether, benzene, petroleum ether, benzene, chloroform, ethyl acetate, ethanol and water respectively. The results obtained in the present investigation indicated M. oleifera pods as a rich source of natural antioxidants.

  1. Thin-Layer Chromatography: Comparative Estimation of Soil’s Atrazine

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    Vijay Kumar

    2013-12-01

    Full Text Available Herbicide atrazine is a broad spectrum herbicide, used worldwide to protect the crops from weeds, but overuse of atrazine have caused the huge environmental problems from few decades. So it is very essential to study and develop the lab based analytical methods, which are important for the detection of atrazine in environment as well as in biological media. In this study we have collected the soils samples from farm fields and extracted the atrazine by Soxhlet method. Also we have extracted the atrazine from formulated grade considered as standard/pure sample in our study. Both extracted/standard and atrazine samples were characterized by UV and FTIR analysis. Further thin layer chromatography was run to check the purity of soil extracted sample.

  2. Reversed-phase thin-layer chromatography behavior of aldopentose derivatives

    Directory of Open Access Journals (Sweden)

    Malbaša Radomir V.

    2012-01-01

    Full Text Available Quantitative structure-retention relationships (QSRR have been used to study the chromatographic behavior of some aldopentose. The behavior of aldopentose derivatives was investigated by means of the reversed-phase thin-layer chromatography (RP TLC on the silica gel impregnated with paraffin oil stationary phases. Binary mixtures of methanol-water, acetone-water and dioxane-water were used as mobile phases. Retention factors, RM0, corresponding to zero percent organic modifier in the aqueous mobile phase was determined. Lipophilicity C0 was calculated as the ratio of the intercept and slope values. There was satisfactory correlation between them and log P values calculated using different theoretical procedures. Some of these correlations offer very good predicting models, which are important for a better understanding of the relationships between chemical structure and retention. The study showed that the hydrophobic parameters RM0 and C0 can be used as a measures of lipophilicity of investigated compounds.

  3. Random forest models of the retention constants in the thin layer chromatography

    CERN Document Server

    Kursa, Miron B; Rudnicki, Witold R

    2011-01-01

    In the current study we examine an application of the machine learning methods to model the retention constants in the thin layer chromatography (TLC). This problem can be described with hundreds or even thousands of descriptors relevant to various molecular properties, most of them redundant and not relevant for the retention constant prediction. Hence we employed feature selection to significantly reduce the number of attributes. Additionally we have tested application of the bagging procedure to the feature selection. The random forest regression models were built using selected variables. The resulting models have better correlation with the experimental data than the reference models obtained with linear regression. The cross-validation confirms robustness of the models.

  4. Assessment of aflatoxin B1 in livestock feed and feed ingredients by high-performance thin layer chromatography

    OpenAIRE

    Korrapati Kotinagu; T. Mohanamba; L. Rathna Kumari

    2015-01-01

    Aim: Detection of aflatoxin B1 in Livestock compound Feed and feed ingredients by high-performance thin layer chromatography (HPTLC). Materials and Methods: Chromatography was performed on HPTLC silica gel 60 F 254, aluminum sheets by CAMAG automatic TLC sampler 4, with mobile phase condition chloroform:acetone:water (28:4:0.06). Extraction of aflatoxin B1 from samples was done as per AOAC method and screening and quantification done by HPTLC Scanner 4 under wavelength 366 nm. Results: ...

  5. Hydrocarbon group-type analysis by thin layer chromatography and scanning densitometry

    Energy Technology Data Exchange (ETDEWEB)

    Membrado, L.; Cebolla, V.L.; Matt, M.; Galvez, E.M.; Domingo, M.P.; Vela, J.; Beregovtsova, N. [CSIC, Zaragoza (Spain)

    2002-07-01

    Hydrocarbon group-type analysis (HGTA) is a common technique for characterization of complex mixtures derived from raw materials such as coal, petroleum, or biomass. In these and other, related, samples, trying to achieve extensive separation of all the components would be very difficult at least, and most of the relevant properties of the samples can be related to the amounts of the different types of hydrocarbon. Groups of interest depend mainly on the nature of the sample, and some kind of liquid chromatography is usually involved in the most common HGTA methods. Thin-layer chromatography (TLC) can nowadays usually be used instead of HPLC, resulting in several advantages in terms of speed, cost, and general convenience. Detection and quantification of the different peaks might involve the use of special equipment, e.g. in TLC-flame ionization detection (FID) methods, although it can also be accomplished by means of UV and fluorescence scanning densitometry. This paper describes a series of TLC-based HGTA methods developed for coal-, biomass-, and petroleum-derived products that give a reasonably general overview of the possibilities of TLC applied to HGTA.

  6. Indirect fluorometric detection techniques on thin layer chromatography and effect of ultrasound on gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Yinfa, Ma.

    1990-12-10

    Thin-layer chromatography (TLC) is a broadly applicable separation technique. It offers many advantages over high performance liquid chromatography (HPLC), such as easily adapted for two-dimensional separation, for whole-column'' detection and for handling multiple samples, etc. However, due to its draggy development of detection techniques comparing with HPLC, TLC has not received the attention it deserves. Therefore, exploring new detection techniques is very important to the development of TLC. It is the principal of this dissertation to present a new detection method for TLC -- indirect fluorometric detection method. This detection technique is universal sensitive, nondestructive, and simple. This will be described in detail from Sections 1 through Section 5. Section 1 and 3 describe the indirect fluorometric detection of anions and nonelectrolytes in TLC. In Section 2, a detection method for cations based on fluorescence quenching of ethidium bromide is presented. In Section 4, a simple and interesting TLC experiment is designed, three different fluorescence detection principles are used for the determination of caffeine, saccharin and sodium benzoate in beverages. A laser-based indirect fluorometric detection technique in TLC is developed in Section 5. Section 6 is totally different from Sections 1 through 5. An ultrasonic effect on the separation of DNA fragments in agarose gel electrophoresis is investigated. 262 refs.

  7. A simplified method for rapid quantification of intracellular nucleoside triphosphates by one-dimensional thin-layer chromatography

    DEFF Research Database (Denmark)

    Jendresen, Christian Bille; Kilstrup, Mogens; Martinussen, Jan

    2011-01-01

    -pyrophosphate (PRPP), and inorganic pyrophosphate (PPi) in cell extracts. The method uses one-dimensional thin-layer chromatography (TLC) and radiolabeled biological samples. Nucleotides are resolved at the level of ionic charge in an optimized acidic ammonium formate and chloride solvent, permitting...

  8. Quantitative Determination of Photosynthetic Pigments in Green Beans Using Thin-Layer Chromatography and a Flatbed Scanner as Densitometer

    Science.gov (United States)

    Valverde, Juan; This, Herve; Vignolle, Marc

    2007-01-01

    A simple method for the quantitative determination of photosynthetic pigments extracted from green beans using thin-layer chromatography is proposed. Various extraction methods are compared, and it is shown how a simple flatbed scanner and free software for image processing can give a quantitative determination of pigments. (Contains 5 figures.)

  9. Extraction of nutraceuticals from Spirulina (blue-green alga): A bioorganic chemistry practice using thin-layer chromatography.

    Science.gov (United States)

    Herrera Bravo de Laguna, Irma; Toledo Marante, Francisco J; Luna-Freire, Kristerson R; Mioso, Roberto

    2015-01-01

    Spirulina is a blue-green alga (cyanobacteria) with high nutritive value. This work provides an innovative and original approach to the consideration of a bioorganic chemistry practice, using Spirulina for the separation of phytochemicals with nutraceutical characteristics via thin-layer chromatography (TLC) plates. The aim is to bring together current research, theory, and practice, and always in accordance with pedagogical ideas.

  10. Extraction of Nutraceuticals from Spirulina (Blue-Green Alga): A Bioorganic Chemistry Practice Using Thin-layer Chromatography

    Science.gov (United States)

    Herrera Bravo de Laguna, Irma; Toledo Marante, Francisco J.; Luna-Freire, Kristerson R.; Mioso, Roberto

    2015-01-01

    Spirulina is a blue-green alga (cyanobacteria) with high nutritive value. This work provides an innovative and original approach to the consideration of a bioorganic chemistry practice, using Spirulina for the separation of phytochemicals with nutraceutical characteristics via thin-layer chromatography (TLC) plates. The aim is to bring together…

  11. The bridge between thin layer chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry: The realization of liquid thin layer chromatography-mass spectrometry (LTLC-MS).

    Science.gov (United States)

    Li, Yafeng; Wang, Jianing; Zhan, Lingpeng; Wleklinski, Michael; Wang, Jiyun; Xiong, Caiqiao; Liu, Huihui; Zhou, Yueming; Nie, Zongxiu

    2016-08-19

    The combination of thin layer chromatography (TLC) and mass spectrometry (MS) has been studied for decades, but for most cases MS detection is done after TLC separation is finished. Here, an online simultaneous TLC-MS analysis system, liquid thin layer chromatography-mass spectrometry (LTLC-MS), is developed which successfully synchronize TLC separation process and MS detection process like GC-MS and HPLC-MS do. And there's no need to use specially designed TLC, just regular TLC plates are enough. LTLC-MS method is composed of a newly developed ambient ionization method, glow discharge-matrix assisted infrared desorption ionization (GD-MAIRDI), and forced-flow TLC (FFTLC) technique, which guarantees the MS detection process does not disturb the TLC separation process throughout the whole analysis. The whole LTLC-MS analysis only need two steps and less than 15min. Mixtures as well as the two main components of a pain relief pills have been successfully analyzed by LTLC-MS. This proof of concept study opens up new possibilities of combining TLC with MS, and will further broaden the application abilities of TLC. PMID:27452991

  12. [Analysis of phthalates in plastic food-packaging bags by thin layer chromatography].

    Science.gov (United States)

    Chen, Hui; Wang, Yuan; Zhu, Ruohua

    2006-01-01

    The method for simultaneous determination of four phthalates, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di (2-ethylhexyl) phthalate (DEHP) in plastic food-packaging bags by thin layer chromatography (TLC) was developed. The plastic food-packaging bags were extracted with ethanol by ultrasonication, then the mixture was filtrated through membrane (0.45 microm). The mixture of ethyl acetate-anhydrous ether-isooctane (1 : 4 : 15, v/v) was used as developing agent on the TLC silica gel plate for development. The filtered liquid was spotted on the TLC plate dealt by acetone, and detected with scanning wavelength of 275 nm and reference wavelength of 340 nm. The qualitative analysis of the phthalates was performed using the R(f) values of the chromatogram. The quantitative analysis was performed with external standard method. Good linearities were obtained for DMP, DEP, DBP and DEHP. The detection limits were 2.1 ng for DMP, 2.4 ng for DEP, 3.4 ng for DBP and 4.0 ng for DEHP. The relative standard deviations (RSDs) of the four phthalates were 2.8% - 3.5%. The recoveries of the four phthalate standards in real sample were 78.58% - 111.04%. The method presented has the advantages of high precision, high sensitivity, small sample size, and simple pretreatment . The method was used to detect the four phthalates in the food-packaging bags. The contents in real samples were close to the results by gas chromatography.

  13. Secondary metabolite credentials of Evolvulus alsinoides by high performance thin layer chromatography (HPTLC).

    Science.gov (United States)

    Gomathi, Duraisamy; Kalaiselvi, Manokaran; Ravikumar, Ganesan; Sophia, Dominic; Gopalakrishnan, Velliyur Kanniappan; Uma, Chandrasekar

    2012-07-01

    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. PMID:23554763

  14. Characterization of drug authenticity using thin-layer chromatography imaging with a mobile phone.

    Science.gov (United States)

    Yu, Hojeong; Le, Huy M; Kaale, Eliangiringa; Long, Kenneth D; Layloff, Thomas; Lumetta, Steven S; Cunningham, Brian T

    2016-06-01

    Thin-layer chromatography (TLC) has a myriad of separation applications in chemistry, biology, and pharmacology due to its simplicity and low cost. While benchtop laboratory sample application and detection systems for TLC provide accurate quantitation of TLC spot positions and densities, there are many applications where inexpensive and portable instruments would greatly expand the applicability of the technology. In this work, we demonstrate identity verification and concentration determination of pharmaceutical compounds via TLC using a custom 3D-printed cradle that interfaces with an ordinary mobile phone. The cradle holds the mobile phone's internal, rear-facing camera in a fixed position relative to a UV lamp and a TLC plate that includes a phosphor in the stationary phase. Analysis of photographs thus reveals the locations and intensities of principal spots of UV--absorbing drugs. Automated image analysis software determines the center location and density of dark spots, which, using integrated calibration spots of known drug compounds and concentrations, can be used to determine if a drug has been diluted or substituted. Two independent image processing approaches have been developed that may be selected based upon the processing capabilities of the smartphone. Each approach is able to discern 5% drug concentration differences. Using single-component solutions of nevirapine, amodiaquine, and paracetamol that have been manually applied, the mobile phone-based detection instrument provides measurements that are equivalent to those obtained with a commercially available lab-based desktop TLC densitometer. PMID:27015410

  15. HPTLC-aptastaining - Innovative protein detection system for high-performance thin-layer chromatography

    Science.gov (United States)

    Morschheuser, Lena; Wessels, Hauke; Pille, Christina; Fischer, Judith; Hünniger, Tim; Fischer, Markus; Paschke-Kratzin, Angelika; Rohn, Sascha

    2016-05-01

    Protein analysis using high-performance thin-layer chromatography (HPTLC) is not commonly used but can complement traditional electrophoretic and mass spectrometric approaches in a unique way. Due to various detection protocols and possibilities for hyphenation, HPTLC protein analysis is a promising alternative for e.g., investigating posttranslational modifications. This study exemplarily focused on the investigation of lysozyme, an enzyme which is occurring in eggs and technologically added to foods and beverages such as wine. The detection of lysozyme is mandatory, as it might trigger allergenic reactions in sensitive individuals. To underline the advantages of HPTLC in protein analysis, the development of innovative, highly specific staining protocols leads to improved sensitivity for protein detection on HPTLC plates in comparison to universal protein derivatization reagents. This study aimed at developing a detection methodology for HPTLC separated proteins using aptamers. Due to their affinity and specificity towards a wide range of targets, an aptamer based staining procedure on HPTLC (HPTLC-aptastaining) will enable manifold analytical possibilities. Besides the proof of its applicability for the very first time, (i) aptamer-based staining of proteins is applicable on different stationary phase materials and (ii) furthermore, it can be used as an approach for a semi-quantitative estimation of protein concentrations.

  16. Molecular Ionization-Desorption Analysis Source (MIDAS) for Mass Spectrometry: Thin-Layer Chromatography

    Science.gov (United States)

    Winter, Gregory T.; Wilhide, Joshua A.; LaCourse, William R.

    2016-02-01

    Molecular ionization-desorption analysis source (MIDAS), which is a desorption atmospheric pressure chemical ionization (DAPCI) type source, for mass spectrometry has been developed as a multi-functional platform for the direct sampling of surfaces. In this article, its utility for the analysis of thin-layer chromatography (TLC) plates is highlighted. Amino acids, which are difficult to visualize without staining reagents or charring, were detected and identified directly from a TLC plate. To demonstrate the full potential of MIDAS, all active ingredients from an analgesic tablet, separated on a TLC plate, were successfully detected using both positive and negative ion modes. The identity of each of the compounds was confirmed from their mass spectra and compared against standards. Post separation, the chemical signal (blue permanent marker) as reference marks placed at the origin and solvent front were used to calculate retention factor (Rf) values from the resulting ion chromatogram. The quantitative capabilities of the device were exhibited by scanning caffeine spots on a TLC plate of increasing sample amount. A linear curve based on peak are, R2 = 0.994, was generated for seven spots ranging from 50 to 1000 ng of caffeine per spot.

  17. Incompatibility studies by high performance thin-layer chromatography: In case of curcumin

    Directory of Open Access Journals (Sweden)

    Alankar Shrivastava

    2013-01-01

    Full Text Available Curcumin[1,7-bis (4-hydroxy-3-methoxy-phenyl hepta-1, 6-diene-3, 5-dione] is one of the component present in the turmeric. Curcumin has been in use for its medicinal benefits since centuries and its therapeutic potential is continuously explored through various researchers throughout the world. To investigate the interaction of curcumin with commonly used excipients such as microcrystalline cellulose, starch, colloidal silica, talc, ascorbic acid, lactose, ethyl cellulose (EC, sodium carboxymethylcellulose (Na-CMC, hydroxyl propyl methyl cellulose and magnesium stearate. High performance thin-layer chromatography (HPTLC is commonly used technique for the determination of phytoconstituents, but its application in incompatibility studies is still not investigated. Thus, we initiated our study with HPTLC followed by Fourier transform infrared and differential scanning calorimetry. Since interaction of curcumin with ascorbic acid, EC, Na-CMC and Mg-stearate confirmed by all three techniques these four excipients should be avoided during the formulation development of curcumin. The presented study also establishes HPTLC′s usefulness in such interaction studies.

  18. Characterization of drug authenticity using thin-layer chromatography imaging with a mobile phone.

    Science.gov (United States)

    Yu, Hojeong; Le, Huy M; Kaale, Eliangiringa; Long, Kenneth D; Layloff, Thomas; Lumetta, Steven S; Cunningham, Brian T

    2016-06-01

    Thin-layer chromatography (TLC) has a myriad of separation applications in chemistry, biology, and pharmacology due to its simplicity and low cost. While benchtop laboratory sample application and detection systems for TLC provide accurate quantitation of TLC spot positions and densities, there are many applications where inexpensive and portable instruments would greatly expand the applicability of the technology. In this work, we demonstrate identity verification and concentration determination of pharmaceutical compounds via TLC using a custom 3D-printed cradle that interfaces with an ordinary mobile phone. The cradle holds the mobile phone's internal, rear-facing camera in a fixed position relative to a UV lamp and a TLC plate that includes a phosphor in the stationary phase. Analysis of photographs thus reveals the locations and intensities of principal spots of UV--absorbing drugs. Automated image analysis software determines the center location and density of dark spots, which, using integrated calibration spots of known drug compounds and concentrations, can be used to determine if a drug has been diluted or substituted. Two independent image processing approaches have been developed that may be selected based upon the processing capabilities of the smartphone. Each approach is able to discern 5% drug concentration differences. Using single-component solutions of nevirapine, amodiaquine, and paracetamol that have been manually applied, the mobile phone-based detection instrument provides measurements that are equivalent to those obtained with a commercially available lab-based desktop TLC densitometer.

  19. Lipid analysis by thin-layer chromatography--a review of the current state.

    Science.gov (United States)

    Fuchs, Beate; Süss, Rosmarie; Teuber, Kristin; Eibisch, Mandy; Schiller, Jürgen

    2011-05-13

    High-performance thin-layer chromatography (HPTLC) is a widely used, fast and relatively inexpensive method of separating complex mixtures. It is particularly useful for smaller, apolar compounds and offers some advantages over HPLC. This review gives an overview about the special features as well as the problems that have to be considered upon the HPTLC analysis of lipids. The term "lipids" is used here in a broad sense and comprises fatty acids and their derivatives as well as substances related biosynthetically or functionally to these compounds. After a short introduction regarding the stationary phases and the methods how lipids can be visualized on an HPTLC plate, the individual lipid classes will be discussed and the most suitable solvent systems for their separation indicated. The focus will be on lipids that are most abundant in biological systems, i.e. cholesterol and its derivates, glycerides, sphingo- and glycolipids as well as phospholipids. Finally, a nowadays very important topic, the combination between HPTLC and mass spectrometric (MS) detection methods will be discussed. It will be shown that this is a very powerful method to investigate the identities of the HPTLC spots in more detail than by the use of common staining methods. Future aspects of HPTLC in the lipid field will be also discussed. PMID:21167493

  20. Resolution of Enantiomers of (RS)-Baclofen by Ligand-Exchange Thin-Layer Chromatography.

    Science.gov (United States)

    Singh, Manisha; Malik, Poonam; Bhushan, Ravi

    2016-05-01

    A new chromatographic method has been developed for direct enantioresolution of (RS)-baclofen by ligand-exchange thin-layer chromatography (TLC) adopting two different approaches; (A) TLC plates were prepared by mixing the ligand exchange reagents (LER) with silica gel slurry and the chromatograms were developed with different achiral solvents or solvents having no chiral additive, and (B) the LER consisting of Cu(II)-l-amino acid complex was used as chiral mobile phase additive and the plain plates of silica gel having no chiral selector were used. Cu(II) acetate and fourl-amino acids (namely,l-tryptophan,l-histidine,l-proline andl-phenylalanine) were used for the preparation of LERs. Spots were located by the use of iodine vapor. Effect of temperature and the mole ratio of Cu(II)-to-amino acid on enantioresolution were also studied. The results for the two methods have been compared, and the issue of involvement of the Cu(II) cation for the best performance of the two methods has been discussed with respect to the same mobile phase.l-Trp proved to be a good ligand using a common mobile phase in each case. PMID:26896346

  1. Nevirapine concentrations in saliva measured by thin layer chromatography and self-reported adherence in patients on antiretroviral therapy at kilimanjaro christian medical centre, Tanzania

    NARCIS (Netherlands)

    George, L.; Muro, E.P.; Ndaro, A.; Dolmans, W.M.; Burger, D.M.; Kisanga, E.R.

    2014-01-01

    BACKGROUND: Thin layer chromatography (TLC) can be used to perform therapeutic drug monitoring in resource-limited settings, where more expensive analytical methods, such as high-performance liquid chromatography or liquid chromatography-mass spectrometry, are not feasible. OBJECTIVES: The aim of th

  2. Separation and Detection of Ceramides by HPLC Followed by Evaporative Light-Scattering Detection and Thin Layer Chromatography

    Institute of Scientific and Technical Information of China (English)

    张琳; 周全; 傅学奇; 陈国强

    2002-01-01

    Ceramides are important signaling molecules involved in a variety of cellular processes, including cell growth, differentiation, and apoptosis. Currently, different methods are used for ceramide analysis, some of which are insensitive or cumbersome. This paper described methods utilizing thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) followed by evaporative light scattering detection (ELSD) to detect ceramide directly in cell extracts without derivatization, which was proved to be efficient and reproducible. Five kinds of ceramides were used as standards. Both TLC and normal-phase HPLC/ELSD results indicate that yeast contains several kinds of ceramides.

  3. A novel high-performance thin layer chromatography method for quantification of long chain aliphatic hydrocarbons from Cissus quadrangularis

    OpenAIRE

    Vandana Jain; Vedang Kinjawadekar; Kirti Laddha

    2016-01-01

    Context: A high-performance thin layer chromatography (HPTLC) is an analytical technique, which can be used for the determination of constituents or marker components in various parts of the plants. Earlier studies have estimated phytoconstituents from the stem and other aerial plant parts of Cissus quadrangularis Linn. Estimation of hydrocarbons can also be successfully done using HPTLC technique using suitable derivatization. Aims: To develop and validate a simple and rapid method for t...

  4. Stability of Y-90 Zevalin: Radiochemical purity evaluation using instant thin layer and size exclusion high performance liquid chromatography

    International Nuclear Information System (INIS)

    Aim: The purpose of the study was to evaluate the stability of typical Y-90 Zevalin (IDEC Pharmaceuticals Corp) patient doses, either maintained at room temperature or refrigerated, using the manufacturer's recommended instant thin layer chromatography procedure and confirming the results using size exclusion high performance liquid chromatography (HPLC) to evaluate radiochemical purity. Material and Methods: Following radiolabeling of Y-90 Zevalin, two patient doses were withdrawn into a 10-ml syringe. One patient dose, consisting of 41.2 mCi Y-90 Zevalin in 10 ml, was refrigerated. The other patient dose, consisting of 31.2 mCi Y-90 Zevalin in 7.3 ml, was maintained at room temperature. At selected time intervals after formulation, ranging from 0.5 to 49 hrs, radiochemical purity evaluations were performed using instant thin layer chromatography (ITLC-SG) with normal saline and size exclusion HPLC using a TSKgel G3000SW molecular sizing column. For each time interval, five separate samples were analyzed and the data statistically summarized. Results: Following initial radiolabeling, the radiochemical purity of all preparations evaluated was greater than 95%, as demonstrated by both chromatographic methods. At 24 hours post radiolabeling, the mean radiochemical purity of Y-90 Zevalin, refrigerated or maintained at room temperature, was 95.4% ± 0.3% (s.d.) and 86.3% ± 1.2% (s.d), respectively using instant thin layer chromatography. At 48 hours post radiolabeling, the mean radiochemical purity of Y-90 Zevalin, refrigerated or maintained at room temperature, was 91.0% ±± 0.8% (s.d.) and 86.0% ± 2.0% (s.d.), respectively using instant thin layer chromatography. In general, size exclusion HPLC confirmed the chromatographic results. With increased time post radiolabeling, an increase in radiolabeled low molecular weight components (Y-90 DTPA) and an increase in radiolabeled high molecular weight components and/or aggregates was observed. These radiochemical

  5. The phytochemical screening and thin layer chromatography results of Jatropha gossypiifolia seeds

    Directory of Open Access Journals (Sweden)

    Anis Nurwidayati

    2013-05-01

    , the intermediary for schistosomiasis is widespread in this region. Eradication has been done by spraying chemical molluscicides. This study aimed to identify the class of chemical compounds in the methanol extract of red castor seed.Methods: The study was conducted in May 2009. Red castor seeds were collected from Palu, Central Sulawesi. Red castor seeds extraction was done by percolation method using methanol solvent. Phytochemical screening test was performed with a tube to detect the compound in red castor bean extract. Screening was followed by thin layer chromatography testing to ensure the screening results of the test tube.Results:Extracts that was produced from 500 grams of red castor dry seed powder with 2500 ml of methanol solvent was 250 ml thick reddish brown fluid. Phytochemical screening with a test tube showed positive results of alkaloid by the formation of deposits in Meyer test, Wagner test, and Dragendorff test. Screening the methanol extracts of red castor seed also showed positive results on saponins by foam test and LiebermanBurchard test. Positive results on Killiani Keller tests and Kedde test suggests that red castor bean extract contains cardenoline and bufadienol. Thin-layer chromatography analysis showed that the red castor bean extract is positive for terpenes with the formation of spots on the silica gel plate when terpenes was sprayed (cerium sulfate reagent. Conclusion: Chemical components contained in the methanol extract of red castor beans consisted of alkaloids, saponins, cardenolin, bufadienol, and terpenes. (Health Science Indones 2012;2:xx-xxKeywords: schistosomiasis, Jatropha gossypifolia, chemical compound

  6. High Performance Thin Layer Chromatography method for analysis of 3,4-methylenedioxymethamphetamine in seized tablets

    Directory of Open Access Journals (Sweden)

    Boris E. Duffau

    2015-12-01

    Full Text Available Context: Consumption of synthetic drugs had increased in recent years, used as a recreational drug by young people who presume that consumption of this drug is harmless for health; however clinical studies have shown that this stimulant and its metabolites are toxic. Due to these reasons, chemical analysis of this illicit drug is crucial from the points of view of occupational medicine, toxicology, and law enforcement with the aim of pursuit the traffic of illegal drug. Aims: Implement and fully validate a rapid and simple method for detection and quantitation of MDMA by High-Performance Thin Layer Chromatography in seized samples. Methods: With the implemented method was analyzed 12 positive samples seized by Chilean police, to found the concentration of MDMA in ecstasy tablets. Results: The method was fully validated, the linearity of the method was evaluated by the calibration curve between 51.0 – 510.0 µg/band (R2 0.9977; limit of detection was 12.1 µg per band, and limit of quantitation was 36.8 µg per band. The precision of the method (RSD was lower than 5.0%. Accuracy was evaluated by determination of the percentage of MDMA recovered by the assay (99.13%, and relative Uncertainty was 6.66%. With this method, it was analyzed real seized samples of MDMA, results showed that all samples contained MDMA and concentration was between 18.15 – 59.84 % w/w. Conclusions: The method is selective, sensitive, and specific, with possible application in forensic analysis. To the best of our knowledge, this is the first report about concentration of MDMA in ecstasy pills in Chile.

  7. Thin-layer chromatography analysis and scavenging activity of marigold (Calendula officinalis L extracts

    Directory of Open Access Journals (Sweden)

    Ćetković Gordana S.

    2003-01-01

    Full Text Available The methanol, petroleum ether, chloroform, ethyl acetate, n-butanol and water extracts were obtained by extraction of marigold flower (Calendula officinalis L. The content of total phenolic compounds, determined by UV spectrophotometric method using the Folin-Ciocalteu reagent, was 15.12 mg/g. The content of total flavonoids, determined by UV spectrophotometric method according to Markham, was 5.13 mg/g. Qualitative determination of phenolic compounds in the extracts was performed by one- and two-dimensional thin-layer chromatography (TLC procedures. The results of one- and two-dimensional TLC analyses showed that different flavonoids and phenolic acids were present in the investigated extracts. The greatest number of flavonoids (rutin, quercetin and some unidentified flavonoid glycosides and phenolic acids (chlorogenic, caffeic, coumaric and vanillic acid were deteminated in methanol extract. The influence of marigold extracts, in concentration range 0.6-1.2 mg/mL, on 2,2’-diphenyl-1-picrylhydrazyl (DPPH free radicals was investigated by electron spin resonance (ESR spectroscopy. All extracts showed scavenging activity (SA in the following order: ethyl acetate > n-butanol > methanol > water > chloroform > petroleum ether. The SA increased with increasing concentration of extracts. The ethyl acetate and n-butanol extracts exibited the most significant SA. These extracts in concentration of 1.2 mg/mL eliminated completely DPPH radicals. The lowest SA had chloroform and petroleum ether extracts (in concentration of 0.6 mg/mL SA=0%. The SA of marigold extracts is attributed to its hydrogen-donating ability and scavenging effect.

  8. Thin-layer chromatography to monitor cholesterol gallstone dissolution by methyl tert-butyl ether.

    Science.gov (United States)

    D'Agostino, H B; vanSonnenberg, E; Schteingart, C D; Hofmann, A F; Casola, G; Mathieson, J R

    1991-07-01

    We describe a simple and inexpensive method of monitoring methyl tert-butyl ether (MTBE) dissolution of cholesterol gallstones with thin-layer chromatography (TLC) in 10 patients. TLC is a routine semiquantitative laboratory method that can be used to measure the cholesterol concentration present in the MTBE and bile mixture aspirated through the cholecystostomy catheter during gallstone dissolution. TLC is practical in the clinical setting because it can be used to determine if gallstone dissolution is occurring and when MTBE lavage is no longer effective. TLC is performed in the laboratory with routine material and is completed in 15 min. Each TLC measurement costs about $1. The procedure provides objective and specific chemical information on effectiveness and progression of gallstone dissolution, apart from the radiologic and sonographic studies. In our study, TLC signaled effective dissolution in the initial phase of gallstone dissolution by detecting large amounts of cholesterol in the MTBE and bile mixture even before a visible change in size or shape of the stone became apparent by transcatheter cholecystography or by sonography (six of 10 patients). Conversely, lack of cholesterol on TLC after 1 hr or more of MTBE infusion indicates that the stones are pigmented or contain substantial calcium. This means that dissolution with MTBE will be ineffective and that solvent infusion should be terminated. In those cases in which dissolution is progressing well, when TLC shows decreasing amounts of cholesterol in the effluent, only residual fragments insoluble to MTBE remain or the stone is sequestered from MTBE; at this point, solvent infusion should be discontinued or the catheter must be repositioned. Monitoring the rate of cholesterol dissolution by TLC provides important complementary information to cholecystography and sonography during gallstone treatment with MTBE. PMID:2048533

  9. Thin-Layer Chromatography/Desorption Electrospray Ionization Mass Spectrometry: Investigation of Goldenseal Alkaloids

    Energy Technology Data Exchange (ETDEWEB)

    Van Berkel, Gary J [ORNL; Tomkins, Bruce A [ORNL; Kertesz, Vilmos [ORNL

    2007-01-01

    Desorption electrospray ionization mass spectrometry was investigated as a means to qualitatively identify and to quantify analytes directly from developed normal-phase thin layer chromatography plates. The atmospheric sampling capillary of a commercial ion trap mass spectrometer was extended to permit sampling and ionization of analytes in bands separated on intact TLC plates (up to 10 cm x 10 cm). A surface positioning software package and the appropriate hardware enabled computer-controlled surface scanning along the length of development lanes or at fixed RF value across the plates versus the stationary desorption electrospray emitter. Goldenseal (Hydrastis canadensis) and related alkaloids and commercial dietary supplements were used as standards and samples. Alkaloid standards and samples were spotted and separated on aluminum- or glass-backed plates using established literature methods. The mass spectral signal levels as a function of desorption spray solvent were investigated with acetonitrile proving superior to methanol. The detection levels (ca. 5 ng each or 14 -28 pmol) in mass spectral full scan mode were determined statistically from the calibration curves (2.5 - 100 pmol) for the standards berberine, palmatine and hydrastinine spotted as a mixture and separated on the plates. Qualitative screening of the major alkaloids present in six different over-the-counter "goldenseal" dietary supplements was accomplished by obtaining full scan mass spectra during surface scans along the development lane in the direction of increasing RF value. In one sample, alkaloids were detected that strongly suggested the presence of at least one additional herb undeclared on the product label. These same data indicated the misidentification of one of the alkaloids in the TLC literature. Quantities of the alkaloids present in two of the samples determined using the mass spectral data were in reasonable agreement with the label values indicating the quantitative ability of

  10. SIMULTANEOUS QUANTIFICATION OF RUTIN AND ISOQUERCITRIN FROM JASMINUM SAMBAC AIT., BY HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    V. Dighe and D. Mestry*

    2012-07-01

    Full Text Available A normal phase high performance thin layer chromatography (HPTLC method has been developed and validated for simultaneous quantitative determination of two flavonoids viz. rutin and isoquercitrin from dried leaf powder of Jasminum sambac Ait. The analysis was performed on TLC aluminum plates precoated with silica gel 60F254. Linear ascending development was carried out in a twin-trough glass chamber saturated with mobile phase comprised of ethyl acetate: methanol: formic acid (10.0:2.0:1.0 v/v/v at room temperature 25±2ºC. The densitometric scanning was done at λ=366nm for both the components in reflectance/absorbance mode. The detector response was linear for concentrations ranging from 0.20µg/band to 0.65µg/band and 0.30µg/band to 1.2µg/band for rutin and isoquercitrin respectively with correlation coefficient of 0.999 for both the components. The method was precise as the value of percent relative standard deviation was found to be less than 2. The amounts of rutin and isoquercitrin in the dried leaf powder of Jasminum sambac Ait. were found to be 0.4962mg/g and 0.6461mg/g respectively. The accuracy of the developed HPTLC method was checked by carrying out the recovery experiment at three different levels, by using standard addition method. The values of percent recovery were found to be 97.60 and 98.84 for rutin and isoquercitrin respectively. This developed HPTLC method for simultaneous determination and quantification of rutin and isoquercitrin present in the dried leaf powder of Jasminum sambac Ait. is simple, rapid , precise and can be used for routine quality control.

  11. Advances on the compositional analysis of glycosphingolipids combining thin-layer chromatography with mass spectrometry.

    Science.gov (United States)

    Müthing, Johannes; Distler, Ute

    2010-01-01

    Glycosphingolipids (GSLs), composed of a hydrophilic carbohydrate chain and a lipophilic ceramide anchor, play pivotal roles in countless biological processes, including infectious diseases and the development of cancer. Knowledge of the number and sequence of monosaccharides and their anomeric configuration and linkage type, which make up the principal items of the glyco code of biologically active carbohydrate chains, is essential for exploring the function of GSLs. As part of the investigation of the vertebrate glycome, GSL analysis is undergoing rapid expansion owing to the application of novel biochemical and biophysical technologies. Mass spectrometry (MS) takes part in the network of collaborations to further unravel structural and functional aspects within the fascinating world of GSLs with the ultimate aim to better define their role in human health and disease. However, a single-method analytical MS technique without supporting tools is limited yielding only partial structural information. Because of its superior resolving power, robustness, and easy handling, high-performance thin-layer chromatography (TLC) is widely used as an invaluable tool in GSL analysis. The intention of this review is to give an insight into current advances obtained by coupling supplementary techniques such as TLC and mass spectrometry. A retrospective view of the development of this concept and the recent improvements by merging (1) TLC separation of GSLs, (2) their detection with oligosaccharide-specific proteins, and (3) in situ MS analysis of protein-detected GSLs directly on the TLC plate, are provided. The procedure works on a nanogram scale and was successfully applied to the identification of cancer-associated GSLs in several types of human tumors. The combination of these two supplementary techniques opens new doors by delivering specific structural information of trace quantities of GSLs with only limited investment in sample preparation. PMID:19609886

  12. Application of RF correction in thin-layer chromatography by means of two reference RF values

    NARCIS (Netherlands)

    Dhont, J.H.; Vinkenborg, C.; Compaan, H.; Ritter, F.J.; Labadie, R.P.; Verweij, A.; Zeeuw, R.A. de

    1972-01-01

    Results of the inter-laboratory experiment described in this paper show that the GALANOS AND KAPOULAS equation can be applied satisfactorily to correct RF values obtained on thin-layer chromatograms in a polar multi-component solvent. Addition of Kieselguhr to the silica gel gives RFc values differ

  13. Simple Identification of the Neutral Chlorinated Auxin in Pea by Thin Layer Chromatography

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1980-01-01

    One of the neutral chlorinated auxins of immature pea seeds was readily identified by thin layer procedures simple enough to serve in student's laboratory courses. 4-Chloroindole-3-acetic acid methyl ester was extracted from 50 g of commercial, frozen peas by either water or acetone, concentrated...

  14. Hydrophobic-hydrophilic monolithic dual-phase layer for two-dimensional thin-layer chromatography coupled with surface-enhanced Raman spectroscopy detection.

    Science.gov (United States)

    Zheng, Binxing; Liu, Yanhua; Li, Dan; Chai, Yifeng; Lu, Feng; Xu, Jiyang

    2015-08-01

    Hydrophobic-hydrophilic monolithic dual-phase plates have been prepared by a two-step polymerization method for two-dimensional thin-layer chromatography of low-molecular-weight compounds, namely, several dyes. The thin 200 μm poly(glycidyl methacrylate-co-ethylene dimethacrylate) layers attached to microscope glass plates were prepared using a UV-initiated polymerization method within a simple glass mold. After cutting and cleaning the specific area of the layer, the reassembled mold was filled with a polymerization mixture of butyl methacrylate and ethylene dimethacrylate and subsequently irradiated with UV light. During the second polymerization process, the former layer was protected from the UV light with a UV mask. After extracting the porogens and hydrolyzing the poly(glycidyl methacrylate-co-ethylene dimethacrylate) area, these two-dimensional layers were used to separate a mixture of dyes with great difference in their polarity using reversed-phase chromatography mode within the hydrophobic layer and then hydrophilic interaction chromatography mode along the hydrophilic area. In the latter dimension only the specific spot was developed further. Detection of the separated dyes could be achieved with surface-enhanced Raman spectroscopy.

  15. Separation of pigment formulations by high-performance thin-layer chromatography with automated multiple development.

    Science.gov (United States)

    Stiefel, Constanze; Dietzel, Sylvia; Endress, Marc; Morlock, Gertrud E

    2016-09-01

    Food packaging is designed to provide sufficient protection for the respective filling, legally binding information for the consumers like nutritional facts or filling information, and an attractive appearance to promote the sale. For quality and safety of the package, a regular quality control of the used printing materials is necessary to get consistently good print results, to avoid migration of undesired ink components into the food and to identify potentially faulty ink batches. Analytical approaches, however, have hardly been considered for quality assurance so far due to the lack of robust, suitable methods for the analysis of rarely soluble pigment formulations. Thus, a simple and generic high-performance thin-layer chromatography (HPTLC) method for the separation of different colored pigment formulations was developed on HPTLC plates silica gel 60 by automated multiple development. The gradient system provided a sharp resolution for differently soluble pigment constituents like additives and coating materials. The results of multi-detection allowed a first assignment of the differently detectable bands to particular chemical substance classes (e.g., lipophilic components), enabled the comparison of different commercially available pigment batches and revealed substantial variations in the composition of the batches. Hyphenation of HPTLC with high resolution mass spectrometry and infrared spectroscopy allowed the characterization of single unknown pigment constituents, which may partly be responsible for known quality problems during printing. The newly developed, precise and selective HPTLC method can be used as part of routine quality control for both, incoming pigment batches and monitoring of internal pigment production processes, to secure a consistent pigment composition resulting in consistent ink quality, a faultless print image and safe products. Hyphenation of HPTLC with the A. fischeri bioassay gave first information on the bioactivity or rather

  16. Flowing atmospheric pressure afterglow combined with laser ablation for direct analysis of compounds separated by thin-layer chromatography

    OpenAIRE

    Cegłowski, Michał; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

    2015-01-01

    A thin-layer chromatography-mass spectrometry (TLC-MS) setup for characterization of low molecular weight compounds separated on standard TLC plates has been constructed. This new approach successfully combines TLC separation, laser ablation, and ionization using flowing atmospheric pressure afterglow (FAPA) source. For the laser ablation, a low-priced 445-nm continuous-wave diode laser pointer, with a power of 1 W, was used. The combination of the simple, low-budget laser pointer and the FAP...

  17. Analysis of the Nucleoside Content of Cordyceps sinensis Using the Stepwise Gradient Elution Technique of Thin-Layer Chromatography

    Institute of Scientific and Technical Information of China (English)

    MA,King-Wah(马敬桦); CHAU,Foo-Tim(周福添); WU,Jian-Yong(吴建勇)

    2004-01-01

    Nucleoside is the main class of active components in Cordyceps sinensis. Thin-layer chromatography (TLC) is one of the most commonly used methods in pharmacopoeias for analyzing chemical components of herbal medicine. Since the isocratic elution method cannot be applied successfully in TLC analysis for separating all the nucleoside components, the stepwise gradient elution has been developed in this work to separate eight nucleoside standards with success. In this way, quantitative analyses of the samples of Cordyceps sinensis were achieved via the proposed TLC procedure coupled with the scanning densitometric techniques of CAMAG and TLCQA methods for qualitative and quantitative analysis.

  18. Peak broadening in paper chromatography and related techniques VI. The efficiency of various kinds of chromatography paper and thin-layer cellulose powder for the separation of amino acids

    NARCIS (Netherlands)

    Ligny, C.L. de; Kok, E.C.M.

    1968-01-01

    The efficiency of several chromatography papers and thin-layer cellulose powders for the separation of amino acids is investigated, using the minimum elution time for a given resolution as the criterion.

  19. Separation of Berberine Hydrochloride and Tetrahydropalmatine and Their Quantitative Analysis with Thin Layer Chromatography Involved with Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Jing Lu

    2015-01-01

    Full Text Available [BMIM]OH was used in mobile and stationary phase of thin layer chromatography (TLC to analyze berberine hydrochloride and tetrahydropalmatine for the first time. Supported imidazole ionic liquid with hydroxide ion on silica gel (SiO2·Im+·OH− was synthesized through simple procedure and characterized by Fourier transform infrared spectroscopy (FT-IR, elemental analysis, and scanning electron microscope (SEM. Moreover, on the plates prepared by SiO2·Im+·OH−, the contents of the above alkaloids in the Chinese patent medicine (CPM of “Stomacheasy” capsule were successfully determined by TLC scanner. The key conditions and chromatographic behaviors were also investigated in detail. According to similar ways, ionic liquids (ILs also can be used in other planar chromatographies in two modes. This study is expected to be helpful in expanding the application of IL and its bonded silica gel in TLC separation field.

  20. Preparation of porous styrenics-based monolithic layers for thin layer chromatography coupled with matrix-assisted laser-desorption/ionization time-of-flight mass spectrometric detection.

    Science.gov (United States)

    Lv, Yongqin; Lin, Zhixing; Tan, Tianwei; Svec, Frantisek

    2013-11-01

    Monolithic 50 μm thin poly(4-methylstyrene-co-chloromethylstyrene-co-divinylbenzene) layers attached to 6.0 cm × 3.3 cm glass plates have been prepared, using a thermally initiated polymerization process. These layers had a well-defined porous structure with a globular morphology demonstrated with SEM images and exhibited superhydrophobic properties characterized with a water contact angle of 157°. They were then used for thin-layer chromatography of peptides and proteins fluorescently labeled with fluorescamine. The spots of individual separated compounds were visualized using UV light, and their identities were confirmed with a matrix-assisted laser desorption/ionization time of flight mass spectrometry. The presence of chloromethylstyrene units in the polymer enabled hypercrosslinking via a Friedel-Crafts alkylation reaction, and led to monoliths with much larger surface areas, which were suitable for separations of small dye molecules.

  1. Chemical and biological characterization of Portuguese própolis using thin-layer chromatography

    OpenAIRE

    Leticia M. Estevinho; Paula, Vanessa Marina Branco; Dias, L. G.

    2013-01-01

    Propolis is a resinous substance obtained by honey bees Apis mellifera, a product considered "natural an8bio8c" which plays an important role in defending the hive, protec8ng it from microorganisms, fungi, bacteria and viruses. This product has a large variety of compounds in its composi8on, giving greater emphasis to the phenolic compounds, which are a>ributed strong an8oxidant and an8microbial ac8vi8es. The main objec8ve of this work is to op8mize the technique of thin layer chroma...

  2. Thin-layer chromatography with flame ionization detection in the characterization of pitches

    Energy Technology Data Exchange (ETDEWEB)

    Cebolla, V.L.; Membrado, L.; Vela, J. [Instituto de Carboquimica, Zaragoza (Spain)] [and others

    1995-12-31

    TLC-FID is a rapid, quality-control oriented technique which joins the advantages of Thin-Layer (TLC) with the possibility of quantification of the separated peaks using a Flame Ionization Detector (FID). In the case of heavy fossil fuels, group-type analysis can be achieved with the possibility of a direct quantification of heavy/polar groups, without any preseparation, and in short analysis times with regard to the current techniques. However, although TLC-FID has been used since the eighties in many fields of Chemistry, results were demonstrated to depend on the technique (analytical system plus methodology) used. This work intends to analyze the fundamental parameters involved in TLC-FID technique using adequate technology and methodology, and to lay the groundwork for a correct group-type characterization of pitches.

  3. Qualitative and quantitative two-dimensional thin-layer chromatography/high performance liquid chromatography/diode-array/electrospray-ionization-time-of-flight mass spectrometry of cholinesterase inhibitors.

    Science.gov (United States)

    Mroczek, Tomasz

    2016-09-10

    Recently launched thin-layer chromatography-mass spectrometry (TLC-MS) interface enabling extraction of compounds directly from TLC plates into MS ion source was unusually extended into two-dimensional thin-layer chromatography/high performance liquid chromatography (2D, TLC/HPLC) system by its a direct connection to a rapid resolution 50×2.1mm, I.D. C18 column compartment followed by detection by diode array (DAD) and electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS). In this way, even not separated bands of complicated mixtures of natural compounds could be analysed structurally, only within 1-2min after development of TLC plates. In comparison to typically applied TLC-MS interface, no ion suppression for acidic mobile phases was observed. Also, substantial increase in ESI-TOF-MS sensitivities and quality of spectra, were noticed. It has been utilised in combination with TLC- based bioautographic approaches of acetylcholinesterase (AChE) inhibitors, However, it can be also applied in any other procedures related to bioactivity (e.g. 2,2-Diphenyl-1-picryl-hydrazyl-DPPH screen test for radicals). This system has been also used for determination of half maximal inhibitory concentration (IC50 values) of the active inhibitor-galanthamine, as an example. Moreover, AChE inhibitory potencies of some of purified plant extracts, never studied before, have been quantitatively measured. This is first report of usage such the 2D TLC/HPLC/MS system both for qualitative and quantitative evaluation of cholinesterase inhibitors in biological matrices.

  4. Rolling--a new application technique for luminescent bacteria on high-performance thin-layer chromatography plates.

    Science.gov (United States)

    Baumgartner, Vera; Hohl, Christopher; Schwack, Wolfgang

    2011-05-13

    High-performance thin-layer chromatography (HPTLC) coupled with bioluminescence detection using Vibrio fischeri bacteria can be used for screening for unknown substances. This is accomplished by dipping the HPTLC plate in an aqueous bacteria solution. Especially polar substances, however, can start to dissolve during this process, which leads to blurring and tailing of the zones on the plate. To overcome this disadvantage, we applied the bacteria solution by rolling. This method has been described for chemical derivatizations, but is very rarely used. The rolling device was made of commercially available household articles. Using octhilinone and methylparaben as test compounds, rolling was compared with dipping. Despite of performing the rolling process manually, the results were reproducible. Depending on the substance and its amount on the HPTLC plate, peaks were narrower, up to a factor of 4 higher and with a higher signal-to-noise ratio than after dipping.

  5. Quantitative Radioassay Methods for Thin-Layer Chromatography: Zonal and Autoradiographic Scans

    International Nuclear Information System (INIS)

    Zonal scanning, external scanning, elution analysis, autoradiographic analysis, and combustion techniques can all be used to determine the distribution of radioactivity along a thin-layer chromatographic strip. The most sensitive techniques for the quantitative radioassay of thin-layer chromatograms (TLC) containing low-energy beta isotopes are liquid-scintillation zonal scanning and densitometric autoradiographic scanning. A report from this laboratory has described a manual instrument for preparing TLC zonal scans. The procedure consists of the quantitative transfer of small zones (1-5 mm) of adsorbent from the chromatostrip to liquid scintillation vials for assay at efficiencies identical to those observed for non-quenched liquid samples. The plotting of the radioactivity contained in adjacent zones along the strip results in a distribution curve called a zonal scan. A completely automated system for the preparation of zonal scans based on the manual prototype has been constructed. Its application to problems of radio purity and to metabolic experiments gives excellent quantification, resolution, and counting efficiency with a variety of adsorbents, compounds, visual indicators, and impregnating agents. Specific activity calculations can be made combining the zonal scan technique with photo densitometric quantitation from H2SO4-charred chromatostrips. The second technique, photo densitometric analysis of autoradiograms, requires less expensive equipment to obtain the radioactive distribution curves, but has the disadvantages of being more time-consuming and of providing poorer resolution than the zonal scans. Krylon is sprayed on the chromatogram to maintain the integrity of the adsorbent when in contact with the film. Autoradiograms of TLC plates are then prepared using Kodak no-screen X-ray film placed in contact with the chromatograms in a special box designed for this purpose. After a proper period of exposure (a guide table for 14C, 3H and 32P exposures

  6. Determination of ivermectin stability by high-performance thin-layer chromatography

    Directory of Open Access Journals (Sweden)

    Mohd. Ali

    2011-06-01

    Full Text Available A rapid, sensi tive and stabi l i ty-signi fying high-performance thin-layer chromatographic (HPTLC method was developed and validated for the quantitative estimation of ivermectin (IVM as a bulk drug and in pharmaceutical formulations. The separation was achieved on Lichrospher TLC aluminum plates pre-coated with silica gel 60F-254 (20cm×10cm×200 :m using n-hexane: acetone: ethylacetate (6.5: 3.5: 0.1 v/v/v as mobi le phase. The densitometric analysis was carried out at 247 nm wavelength. Compact spots of IVM were found at Rf = 26±0.02. For proposed procedure, linearity (r2 = 0.9989, limit of quantification (24.9 ng spot−1, limit of detection (8.22 ng spot−1 recovery (98.25–100.16%, and inter as well intra-day precision (≤2.21 was found to be satisfactory. We have synthesized polymeric nanoparticles encapsulated formulat ion of ivermectin (IVM-NPs ; ut i l izing micel lar aggregates of cross-l inked random copolymer Nisopropylacrylamide (NIPAAM with N-vinyl-2-pyrrolidone (VP and polyethyleneglycol monoacrylate (PEG-A for lymphat ic targeting and i t was also quanti f ied by the developed method. IVM and formulations were subjected to acid and alkali hydrolysis, oxidation and photo-degradation. The drug undergoes degradation under acidic, basic, light and oxidation conditions. This indicates that the drug is susceptible to acid- base hydrolysis, oxidation and photo-oxidation and the developed method is selective for quantifying IVM even in the presence of degradatnts. The method was applicable for routine analysis and stability testing of IVM in pharmaceutical drug delivery systems. As the method could effectively separate the said drug from its degradation products, it can be employed as a stability indicating one.

  7. Assessment of aflatoxin B1 in livestock feed and feed ingredients by high-performance thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Korrapati Kotinagu

    2015-12-01

    Full Text Available Aim: Detection of aflatoxin B1 in Livestock compound Feed and feed ingredients by high-performance thin layer chromatography (HPTLC. Materials and Methods: Chromatography was performed on HPTLC silica gel 60 F 254, aluminum sheets by CAMAG automatic TLC sampler 4, with mobile phase condition chloroform:acetone:water (28:4:0.06. Extraction of aflatoxin B1 from samples was done as per AOAC method and screening and quantification done by HPTLC Scanner 4 under wavelength 366 nm. Results: A total of 97 livestock feed (48 and feed ingredients (49 samples received from different livestock farms and farmers were analyzed for aflatoxin B1of which 29 samples were contaminated, constituting 30%. Out of 48 livestock compound feed samples, aflatoxin B1 could be detected in 16 samples representing 33%, whereas in livestock feed ingredients out of 49 samples, 13 found positive for aflatoxin B1 representing 24.5%. Conclusion: HPTLC assures good recovery, precision, and linearity in the quantitative determination of aflatoxin B1 extracted from Livestock compound feed and feed ingredients. As more number of feed and feed ingredients are contaminated with aflatoxin B1 which causes deleterious effects in both animal and human beings, so there is a need for identifying the source of contamination, executing control measures, enabling better risk assessment techniques, and providing economic benefits.

  8. Determination of 2-Aminoacetophenone in wine by high-performance thin-layer chromatography-fluorescence detection.

    Science.gov (United States)

    Horlacher, Nora; Schwack, Wolfgang

    2016-02-01

    2-Aminoacetophenone (AAP) is closely correlated with the appearance of the sensory phenomenon of UTA ("untypical aging off-flavor") in wine. AAP analyses are generally performed by gas chromatography and mass selective detection (GC/MS), when AAP is extracted from wines by liquid-liquid, solid-liquid or solid phase microextraction. Here we present a rapid, selective and sensitive method for the determination of AAP in wine by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD). As internal standard, 2-amino-4-methoxyacetophenone was used. Liquid-liquid extraction with t-butyl methyl ether was followed by a basic cleanup of the extracts, which were applied onto HPTLC amino plates developed with methylene chloride/toluene (7+3, v/v) as mobile phase. Dipping the dried plate into hexane-paraffin solution enhanced fluorescence that was scanned at 366/>400nm. Limits of detection and quantitation were determined to be 0.1 and 0.3μgL(-1) wine, respectively, while only AAP concentrations >0.5μgL(-1) result in UTA. Recoveries were near 100% for model, white, rosé and red wines. Thus, the HPTLC-FLD method enables the analysis of AAP in wines clearly below the odor thresholds and represents a rapid and convenient screening alternative to existing GC/MS methods.

  9. COMBINED INFORMATION FROM RETARDATION FACTOR (RF) VALUES AND COLOR-REACTIONS ON THE PLATE GREATLY ENHANCES THE IDENTIFICATION POWER OF THIN-LAYER CHROMATOGRAPHY IN SYSTEMATIC TOXICOLOGICAL ANALYSIS

    NARCIS (Netherlands)

    HEGGE, HFJ; FRANKE, JP; DEZEEUW, RA

    1991-01-01

    A numerical color coding system has been developed to describe the colors of spots obtained after using location reagents in thin-layer chromatography (TLC). This system makes color reactions on the plate amenable to computer handling, so that the retardation factor (Rf) values plus color reactions

  10. Separation of the Carotenoid Bixin from Annatto Seeds Using Thin-Layer and Column Chromatography

    Science.gov (United States)

    McCullagh, James V.; Ramos, Nicholas

    2008-01-01

    In this experiment the carotenoid bixin is isolated from annatto ("Bixa orellana") seeds using column chromatography. The experiment has several key advantages over previous pigment separation experiments. First, unlike other experiments significant quantities of the carotenoid (typically 20 to 25 mg) can be isolated from small quantities of plant…

  11. Method development for Lawsone estimation in Trichup herbal hair powder by high-performance thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Maunang M Patel

    2013-01-01

    Full Text Available A simple, specific, accurate, precise and robust high-performance thin-layer chromatographic method has been developed and validated for estimation of Lawsone in Trichup herbal hair powder (coded as a THHP, polyherbal formulation. The chromatographic development was carried out on aluminum plates pre-coated with silica gel 60F 254 and good resolution was achieved with Toluene: Ethyl acetate: Glacial acetic acid (8:1:1 v/v/v as mobile phase. Lawsone detection was carried out densitometrically at 277 nm and obtained retardation factor value was 0.46 ± 0.02. The method was validated with respect to specificity, linearity, accuracy, precision and robustness. The calibration curve was achieved to be linear over a range of 5-60 μg/ml and regression coefficient was obtained 0.998. Accuracy of chromatographic method was evaluated by standard addition method; recovery was obtained 99.25 ± 0.61% . The peak purity of Lawsone was achieved 0.999 r. Relative standard deviation for intraday and inter-day precision was 0.37-0.56% and 0.42-0.55%, respectively. The limit of detection and limit of quantification of the Lawsone were found to be 1.08 μg/m land 3.28 μg/ml, respectively. This result shows that the method was well validated. In the present study, the Lawsone content was found 0.322 ± 0.014% in THHP. This study reveals that the proposed high performance thin layer chromatography method is accurate, fast and cost- effective for routine estimation of Lawsone in polyherbal formulation.

  12. Chromatography.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  13. Determination of Four Major Saponins in Skin and Endosperm of Seeds of Horse Chestnut (Aesculus Hippocastanum L.) Using High Performance Liquid Chromatography with Positive Confirmation by Thin Layer Chromatography

    OpenAIRE

    Zead Helmi Mahmoud Abudayeh; Khaldun Mohammad Al Azzam; Ahmad Naddaf; Uliana Vladimirovna Karpiuk; Viktoria Sergeevna Kislichenko

    2015-01-01

    urpose: To separate and quantify four major saponins in the extracts of the skin and the endosperm of seeds of horse chestnut (Aesculus hippocastanum L.) using ultrasonic solvent extraction followed by a high performance liquid chromatography-diode array detector (HPLC-DAD) with positive confirmation by thin layer chromatography (TLC). Methods: The saponins: escin Ia, escin Ib, isoescin Ia and isoescin Ib were extracted using ultrasonic extraction method. The optimized ex...

  14. Plasma jet desorption atomization-atomic fluorescence spectrometry and its application to mercury speciation by coupling with thin layer chromatography.

    Science.gov (United States)

    Liu, Zhifu; Zhu, Zhenli; Zheng, Hongtao; Hu, Shenghong

    2012-12-01

    A novel plasma jet desorption atomization (PJDA) source was developed for atomic fluorescence spectrometry (AFS) and coupled on line with thin layer chromatography (TLC) for mercury speciation. An argon dielectric barrier discharge plasma jet, which is generated inside a 300 μm quartz capillary, interacts directly with the sample being analyzed and is found to desorb and atomize surface mercury species rapidly. The effectiveness of this PJDA surface sampling technique was demonstrated by measuring AFS signals of inorganic Hg(2+), methylmercury (MeHg), and phenylmercury (PhHg) deposited directly on TLC plate. The detection limits of the proposed PJDA-AFS method for inorganic Hg(2+), MeHg, and PhHg were 0.51, 0.29, and 0.34 pg, respectively, and repeatability was 4.7%, 2.2%, and 4.3% for 10 pg Hg(2+), MeHg, and PhHg. The proposed PJDA-AFS was also successfully coupled to TLC for mercury speciation. Under optimized conditions, the measurements of mercury dithizonate (Hg-D), methylmercury dithizonate (MeHg-D), and phenylmercury dithizonate (PhHg-D) could be achieved within 3 min with detection limits as low as 8.7 pg. The combination of TLC with PJDA-AFS provides a simple, cost-effective, relatively high-throughput way for mercury speciation. PMID:23153091

  15. Simultaneous determination of withanolide A and bacoside A in spansules by high-performance thin-layer chromatography

    Directory of Open Access Journals (Sweden)

    P B Shinde

    2011-01-01

    Full Text Available The objective of this work was to develop and validate a simple, rapid, precise, and accurate high performance thin layer chromatography method for simultaneous determination of withanolide A and bacoside A in combined dosage form. The stationary phase used was silica gel G60F 254 . The mobile phase used was mixture of ethyl acetate: methanol: toluene: water (4:1:1:0.5 v/v/v/v. The detection of spots was carried out at 320 nm using absorbance reflectance mode. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 200 to 800 ng/spot for withanolide A and 50 to 350 ng/spot for bacoside A. The limit of detection and limit of quantification for the withanolide A were found to be 3.05 and 10.06 ng/spot, respectively and for bacoside A 8.3 and 27.39 ng/spot, respectively. The proposed method can be successfully used to determine the drug content of marketed formulation.

  16. Simultaneous determination of withanolide a and bacoside a in spansules by high-performance thin-layer chromatography.

    Science.gov (United States)

    Shinde, P B; Aragade, P D; Agrawal, M R; Deokate, U A; Khadabadi, S S

    2011-03-01

    The objective of this work was to develop and validate a simple, rapid, precise, and accurate high performance thin layer chromatography method for simultaneous determination of withanolide A and bacoside A in combined dosage form. The stationary phase used was silica gel G60F(254). The mobile phase used was mixture of ethyl acetate: methanol: toluene: water (4:1:1:0.5 v/v/v/v). The detection of spots was carried out at 320 nm using absorbance reflectance mode. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 200 to 800 ng/spot for withanolide A and 50 to 350 ng/spot for bacoside A. The limit of detection and limit of quantification for the withanolide A were found to be 3.05 and 10.06 ng/spot, respectively and for bacoside A 8.3 and 27.39 ng/spot, respectively. The proposed method can be successfully used to determine the drug content of marketed formulation.

  17. Thin-layer chromatography with UV-scanning detection for quantitative analysis of coal-derived products

    Energy Technology Data Exchange (ETDEWEB)

    Vela, J.; Cebolla, V.L.; Membrado, L.; Ferrando, A.C. [University of Zaragoza, Zaragoza (Spain). Dept. of Analytical Chemistry

    1998-07-01

    Quantitative analysis of hydrocarbon groups (HGTA) is important in the characterization of products derived from coal conversion. The heaviest products are usually analyzed by thin-layer chromatography with flame-ionization detection (TLC-FID). TLC with ultraviolet (UV) scanning densitometry was investigated as an alternative to TLC-FID for the rapid determination of aromatic, polar, and noneluted compounds in coal-derived products. The results obtained show that TLC-UV is adequate in terms of speed, repeatability, and quantitative analysis, and furnishes results similar to those obtained by TLC-FID. Preparative TLC enables isolation of fractions suitable for preparative purposes and is less time-consuming (hours rather than days) than LC methods. Rapid calibration of TLC-UV is possible by use of fractions isolated by preparative TLC (derived from the actual fossil fuels to be analyzed) as external standards. A method of fast internal calibration has been tested for hydrocarbon group-type analysis. Direct acquisition of UV spectra from the separated peaks can be used to determine whether this method of calibration is applicable to the sample.

  18. Simple, Rapid Mycobacterium ulcerans Disease Diagnosis from Clinical Samples by Fluorescence of Mycolactone on Thin Layer Chromatography.

    Directory of Open Access Journals (Sweden)

    Anita Wadagni

    2015-11-01

    Full Text Available Mycobacterium ulcerans infection, known as Buruli ulcer, is a disease of the skin and subcutaneous tissues which is an important but neglected tropical disease with its major impact in rural parts of West and Central Africa where facilities for diagnosis and management are poorly developed. We evaluated fluorescent thin layer chromatography (f-TLC for detection of mycolactone in the laboratory using samples from patients with Buruli ulcer and patients with similar lesions that gave a negative result on PCR for the IS2404 repeat sequence of M. ulcerans.Mycolactone and DNA extracts from fine needle aspiration (FNA, swabs and biopsy specimen were used to determine the sensitivity and specificity of f-TLC when compared with PCR for the IS2404. For 71 IS2404 PCR positive and 28 PCR negative samples the sensitivity was 73.2% and specificity of 85.7% for f-TLC. The sensitivity was similar for swabs (73%, FNAs (75% and biopsies (70%.We have shown that mycolactone can be detected from M. ulcerans infected skin tissue by f-TLC technique. The technique is simple, easy to perform and read with minimal costs. In this study it was undertaken by a member of the group from each endemic country. It is a potentially implementable tool at the district level after evaluation in larger field studies.

  19. Comparative study on the inclusion behaviour of cyclodextrin derivatives with venoruton and rutin by thin layer chromatography.

    Science.gov (United States)

    Guo, Xiliang; Shuang, Shaomin; Wang, Xiaoping; Dong, Chuan; Pan, Jinghao; Aboul-Enein, Hassan Y

    2004-10-01

    The interaction of rutin and venoruton (troxerutin), with alpha-, beta- and gamma-cyclodextrin (CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and methyl-beta-cyclodextrin (M-beta-CD) was investigated by reversed-phase thin layer chromatography on polyamide plates. A mobile phase consisted of NH(4)OH; NH(4)Cl buffer solution containing various CD concentrations (pH = 9.7, 20 degrees C) was used as mobile phase. The equilibrium constants (K(f)) and the retention factor (R(f)) were determined and used to study the inclusion process. The in fluence of CDs on the solubility of rutin and venoruton was characterized by R(M) values and the increasing hydrophilicity of drugs. The results show that the inclusion capacity of cyclodextrins follows the order HP-beta-CD > M-beta-CD > beta-CD > gamma-CD, and rutin is more easily included by the studied cyclodextrins than venoruton. In addition, the thermodynamic parameters (Delta H, Delta S) for the formation of complexes were obtained from the van't Hoff equation, displaying the enthalpy-entropy compensation effect.

  20. A novel high-performance thin layer chromatography method for quantification of long chain aliphatic hydrocarbons from Cissus quadrangularis

    Directory of Open Access Journals (Sweden)

    Vandana Jain

    2016-08-01

    Full Text Available Context: A high-performance thin layer chromatography (HPTLC is an analytical technique, which can be used for the determination of constituents or marker components in various parts of the plants. Earlier studies have estimated phytoconstituents from the stem and other aerial plant parts of Cissus quadrangularis Linn. Estimation of hydrocarbons can also be successfully done using HPTLC technique using suitable derivatization. Aims: To develop and validate a simple and rapid method for the estimation of long chain aliphatic hydrocarbons from the leaves of C. quadrangularis using HPTLC technique. Methods: Precoated silica gel 60 F254 plates were used as stationary phase. The mobile phase used was hexane (100 %. The detection of spots was carried out using berberine sulphate as detecting reagent. Results: The method was validated in terms of linearity, sensitivity, accuracy, and precision. Linearity range was found to be 2-10 µg/mL, limit of detection 0.127 µg/mL, and limit of quantification 0.384 µg/mL. Conclusions: A novel, simple, accurate, precise and sensitive HPTLC method has been developed and validated for the estimation of long chain aliphatic hydrocarbons obtained from the leaves of C. quadrangularis Linn.

  1. Detection of adulterated copaiba (Copaifera multijuga Hayne oil-resins by refractive index and thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Karol de S. Barbosa

    2009-03-01

    Full Text Available The refractive indices (RI of the eight samples of copaiba oils, collected for this study at RDS Tupé ranged from 1.50284 to 1.50786. The thin layer chromatography (TLC plates of these oils revealed with anisaldehyde-sulphuric acid reagent showed dark lilac stains with several small stains at low Rf and a large rounded stain at high Rf. On the other hand, the twelve copaiba oils purchased at local markets presented RI between 1.48176 and 1.50886, and the TLC plates, showed as general profile blue stains, with smaller superimposed stains at low Rf, bigger superimposed stains like elongated stain at high Rf and a colorless rounded stain at middle Rf. Among 12 purchased oils at local markets, a three oil-resins presented similar RI and TLC profile to those observed for collected copaiba oils; b six oils showed same RI and TLC profiles to those observed for soybean oil; c three samples presented RI near to those showed by copaiba oil-resin, however the TLC profile was near to profile observed for a prepared mixture soybean oil: copaiba oil, two samples with 3:1 proportion and one sample with 1:3 proportion. Therefore, the RI determination and the TLC profiles could be considered rapid and efficient procedures for detection of vegetal oil in the copaiba oil-resins.

  2. Forensic Analysis of Blue Ball point Pen Inks on Questioned Documents by High Performance Thin Layer Chromatography Technique (HPTLC)

    International Nuclear Information System (INIS)

    Nowadays, crimes related to forged documents are increasing. Any erasure, addition or modification in the document content always involves the use of writing instrument such as ball point pens. Hence, there is an evident need to develop a fast and accurate ink analysis protocol to solve this problem. This study is aimed to determine the discrimination power of high performance thin layer chromatography (HPTLC) technique for analyzing a set of blue ball point pen inks. Ink samples deposited on paper were extracted using methanol and separated via a solvent mixture of ethyl acetate, methanol and distilled water (70: 35: 30, v/ v/ v). In this method, the discrimination power of 89.40 % was achieved, which confirm that the proposed method was able to differentiate a significant number of pen-pair samples. In addition, composition of blue pen inks was found to be homogeneous (RSD < 2.5 %) and the proposed method showed good repeatability and reproducibility (RSD < 3. 0%). As a conclusion, HPTLC is an effective tool to separate blue ball point pen inks. (author)

  3. High performance thin layer chromatography fingerprinting, phytochemical and physico-chemical studies of anti-diabetic herbal extracts

    Science.gov (United States)

    Itankar, Prakash R.; Sawant, Dattatray B.; Tauqeer, Mohd.; Charde, Sonal S.

    2015-01-01

    Introduction: Herbal medicines have gained increasing popularity in the last few decades, and this global resurgence of herbal medicines increases their commercial value. However, this increasing demand has resulted in a decline in their quality, primarily due to a lack of adequate regulations pertaining to herbal medicines. Aim: To develop an optimized methodology for the standardization of herbal raw materials. Materials and Methods: The present study has been designed to examine each of the five herbal anti-diabetic drugs, Gymnema sylvester R. Br., Pterocarpus marsupium Roxburgh., Enicostema littorale Blume., Syzygium cumini (L.) Skeels. and Emblica officinalis Gaertn. The in-house extracts and marketed extracts were evaluated using physicochemical parameters, preliminary phytochemical screening, quantification of polyphenols (Folin–Ciocalteu colorimetric method) and high performance thin layer chromatography (HPTLC) fingerprint profiling with reference to marker compounds in plant extracts. Results: All the plants mainly contain polyphenolic compounds and are quantified in the range of 3.6–21.72% w/w. E. officinalis contain the highest and E. littorale contain the lowest content of polyphenol among plant extracts analyzed. HPTLC fingerprinting showed that the in-house extracts were of better quality than marketed extracts. Conclusion: The results obtained from the study could be utilized for setting limits for the reference phytoconstituents (biomarker) for the quality control and quality assurance of these anti-diabetic drugs. PMID:27011722

  4. Flowing atmospheric pressure afterglow combined with laser ablation for direct analysis of compounds separated by thin-layer chromatography.

    Science.gov (United States)

    Cegłowski, Michał; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

    2016-01-01

    A thin-layer chromatography-mass spectrometry (TLC-MS) setup for characterization of low molecular weight compounds separated on standard TLC plates has been constructed. This new approach successfully combines TLC separation, laser ablation, and ionization using flowing atmospheric pressure afterglow (FAPA) source. For the laser ablation, a low-priced 445-nm continuous-wave diode laser pointer, with a power of 1 W, was used. The combination of the simple, low-budget laser pointer and the FAPA ion source has made this experimental arrangement broadly available, also for small laboratories. The approach was successfully applied for the characterization of low molecular weight compounds separated on TLC plates, such as a mixture of pyrazole derivatives, alkaloids (nicotine and sparteine), and an extract from a drug tablet consisting of paracetamol, propyphenazone, and caffeine. The laser pointer used was capable of ablating organic compounds without the need of application of any additional substances (matrices, staining, etc.) on the TLC spots. The detection limit of the proposed method was estimated to be 35 ng/cm(2) of a pyrazole derivative.

  5. Flowing atmospheric pressure afterglow combined with laser ablation for direct analysis of compounds separated by thin-layer chromatography.

    Science.gov (United States)

    Cegłowski, Michał; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

    2016-01-01

    A thin-layer chromatography-mass spectrometry (TLC-MS) setup for characterization of low molecular weight compounds separated on standard TLC plates has been constructed. This new approach successfully combines TLC separation, laser ablation, and ionization using flowing atmospheric pressure afterglow (FAPA) source. For the laser ablation, a low-priced 445-nm continuous-wave diode laser pointer, with a power of 1 W, was used. The combination of the simple, low-budget laser pointer and the FAPA ion source has made this experimental arrangement broadly available, also for small laboratories. The approach was successfully applied for the characterization of low molecular weight compounds separated on TLC plates, such as a mixture of pyrazole derivatives, alkaloids (nicotine and sparteine), and an extract from a drug tablet consisting of paracetamol, propyphenazone, and caffeine. The laser pointer used was capable of ablating organic compounds without the need of application of any additional substances (matrices, staining, etc.) on the TLC spots. The detection limit of the proposed method was estimated to be 35 ng/cm(2) of a pyrazole derivative. PMID:26563110

  6. Thin-layer chromatography-densitometric analysis of alpha-mangostin content in Garcinia mangostana fruit rind extracts.

    Science.gov (United States)

    Pothitirat, Werayut; Gritsanapan, Wandee

    2008-01-01

    The fruit rinds of mangosteen (Garcinia mangostana Linn.) have long been used as traditional medicines for treatment of skin infections, wounds, and diarrhea. A simple thin-layer chromatography (TLC)-densitometric method has been developed for the simultaneous quantification of alpha-mangostin in the extracts from unripe and ripe fruit rinds of G. mangostana. It was found in the ranges of 10.48 +/- 0.83 and 16.65 +/- 0.38% (w/w) in the dried unripe and ripe fruit rinds, respectively. The method was validated for linearity, precision, accuracy, limit of detection (LOD), and limit of quantitation (LOQ). The linearity was found over the range of 100-500 ng/spot with regression coefficient 0.999. Intraday and interday precision studies showed the relative standard deviation was <2%. Accuracy of the method was determined by a recovery study conducted at 3 different levels, and the average recovery was 99.49%. The LOD and LOQ were 40 and 100 ng, respectively. The proposed TLC-densitometric method was found to be simple, precise, specific, sensitive, and accurate. This method can be used for routine quality control of raw material of G. mangostana fruit rind, extract, and its products. It also can be applied in quantifying this marker compound in other drugs.

  7. Development and validation of a high-performance thin layer chromatography method for the determination of cholesterol concentration

    Directory of Open Access Journals (Sweden)

    Jinu John

    2015-06-01

    Full Text Available An accurate, sensitive, precise, reliable, and quick method for the determination of cholesterol content by high-performance thin layer chromatography is developed. In this method, aluminum-backed precoated silica gel 60 F254 plates were used as the stationary phase and the samples were sprayed with the help of CAMAG sample applicator Linomat 5. The chromatogram was developed with the mobile phase consisting of chloroform:methanol (9.5:0.5, v/v. The samples were detected using CAMAG Scanner 4 and evaluated using the method developed on winCATS software. Densitometric analysis of cholesterol was performed in absorbance mode at 200 nm. In this solvent system, cholesterol gave a compact spot with an Rf value of 0.63 ± 0.03. The linear regression analysis of data for the calibration curve showed good linearity over a concentration range of 2–7 μg/spot with a regression value of 0.99933 and standard deviation of 1.44%. The limit of detection and limit of quantification were found to be 100 ng/spot and 500 ng/spot, respectively. Using the developed method, the concentration of cholesterol in the saponified and unsaponified egg yolk sample was determined. This method was found to be reproducible and can even be used for samples containing complex matrices.

  8. Thin Layer Chromatography-Bioautography and Gas Chromatography-Mass Spectrometry of Antimicrobial Leaf Extracts from Philippine Piper betle L. against Multidrug-Resistant Bacteria

    Science.gov (United States)

    Valle, Demetrio L.; Puzon, Juliana Janet M.; Cabrera, Esperanza C.

    2016-01-01

    This study isolated and identified the antimicrobial compounds of Philippine Piper betle L. leaf ethanol extracts by thin layer chromatography- (TLC-) bioautography and gas chromatography-mass spectrometry (GC-MS). Initially, TLC separation of the leaf ethanol extracts provided a maximum of eight compounds with Rf values of 0.92, 0.86, 0.76, 0.53, 0.40, 0.25, 0.13, and 0.013, best visualized when inspected under UV 366 nm. Agar-overlay bioautography of the isolated compounds demonstrated two spots with Rf values of 0.86 and 0.13 showing inhibitory activities against two Gram-positive multidrug-resistant (MDR) bacteria, namely, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The compound with an Rf value of 0.86 also possessed inhibitory activity against Gram-negative MDR bacteria, namely, carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae and metallo-β-lactamase-producing Acinetobacter baumannii. GC-MS was performed to identify the semivolatile and volatile compounds present in the leaf ethanol extracts. Six compounds were identified, four of which are new compounds that have not been mentioned in the medical literature. The chemical compounds isolated include ethyl diazoacetate, tris(trifluoromethyl)phosphine, heptafluorobutyrate, 3-fluoro-2-propynenitrite, 4-(2-propenyl)phenol, and eugenol. The results of this study could lead to the development of novel therapeutic agents capable of dealing with specific diseases that either have weakened reaction or are currently not responsive to existing drugs. PMID:27478476

  9. Development and validation of high-performance liquid chromatography and high-performance thin-layer chromatography methods for the quantification of khellin in Ammi visnaga seed

    Directory of Open Access Journals (Sweden)

    Abid Kamal

    2015-01-01

    Full Text Available Objective: The present study was used to design simple, accurate and sensitive reversed phase-high-performance liquid chromatography RP-HPLC and high-performance thin-layer chromatography (HPTLC methods for the development of quantification of khellin present in the seeds of Ammi visnaga. Materials and Methods: RP-HPLC analysis was performed on a C18 column with methanol: Water (75: 25, v/v as a mobile phase. The HPTLC method involved densitometric evaluation of khellin after resolving it on silica gel plate using ethyl acetate: Toluene: Formic acid (5.5:4.0:0.5, v/v/v as a mobile phase. Results: The developed HPLC and HPTLC methods were validated for precision (interday, intraday and intersystem, robustness and accuracy, limit of detection and limit of quantification. The relationship between the concentration of standard solutions and the peak response was linear in both HPLC and HPTLC methods with the concentration range of 10–80 μg/mL in HPLC and 25–1,000 ng/spot in HPTLC for khellin. The % relative standard deviation values for method precision was found to be 0.63–1.97%, 0.62–2.05% in HPLC and HPTLC for khellin respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.53% in HPLC and 100.08% in HPTLC for khellin. Conclusions: The developed HPLC and HPTLC methods for the quantification of khellin were found simple, precise, specific, sensitive and accurate which can be used for routine analysis and quality control of A. visnaga and several formulations containing it as an ingredient.

  10. Qualitative and quantitative analysis of four species of Curcuma rhizomes using twice development thin layer chromatography.

    Science.gov (United States)

    Zhang, J S; Guan, J; Yang, F Q; Liu, H G; Cheng, X J; Li, S P

    2008-11-01

    The rhizomes of Curcuma phaeocaulis, Curcuma kwangsiensis, Curcuma wenyujin and Curcuma longa are used as Ezhu or Jianghuang in traditional Chinese medicine for a long time. Due to their similar morphological characters, it is difficult to distinguish their origins of raw materials used in clinic. In this study, a simple, rapid and reliable twice development TLC method was developed for qualitative and quantitative analysis of the four species of Curcuma rhizomes. The chromatography was performed on silica gel 60F(254) plate with chloroform-methanol-formic acid (80:4:0.8, v/v/v) and petroleum ether-ethyl acetate (90:10, v/v) as mobile phase for twice development. The TLC markers were colorized with 1% vanillin-H(2)SO(4) solution. The four species of Curcuma were easily discriminated based on their characteristic TLC profiles, and simultaneous quantification of eight compounds, including bisdemethoxycurcumin, demethoxycurcumin, curcumine, curcumenol, curcumol, curdione, furanodienone and curzerene, in Curcuma were also performed densitometrically at lambda(scan)=518nm and lambda(reference)=800 nm. The investigated compounds had good linearity (r(2)>0.9905) within test ranges. Therefore, the developed TLC method can be used for quality control of Curcuma rhizomes. PMID:18722068

  11. Monitoring of monooctanoyl phosphatidylcholine synthesis by enzymatic acidolysis between soybean phosphatidylcholine and caprylic acid by thin-layer chromatography with a flame ionization detector

    DEFF Research Database (Denmark)

    Vikbjerg, Anders Falk; Mu, Huiling; Xu, Xuebing

    2005-01-01

    migration is taking place during reaction since the lipase is claimed to be 1,3-specific. The TLC-FID method offers a simple and cheap technique for elucidation of product and by-product formation during enzyme-catalyzed reactions for production of phospholipids containing mixtures of long- and medium......Thin-layer chromatography with flame ionization detector (TLC-FID) method was used for monitoring the production of structured phospholipids (ML-type: L-long chain fatty acids; M-medium chain fatty acids) by enzyme-catalyzed acidolysis between soybean phosphatidylcholine (PC) and caprylic acid....... It was found that the structured PC fractionated into 2-3 distinct bands on both plate thin layer chromatography (TLC) and Chromarod TLC. These 3 bands represented PC of LL-type, ML-type and MM-type, respectively. The TLC-FID method was applied in the present study to examine the influence of enzyme dosage...

  12. Algerian mint species: high performance thin layer chromatography quantitative determination of rosmarinic acid and in vitro inhibitory effects on linoleic acid peroxidation

    OpenAIRE

    Brahmi Fatiha; Madani Khodir; Stévigny Caroline; Chibane Mohamed; Duez Pierre

    2014-01-01

    Objective: To determine the quantitative paremeters of rosmarinic acid in Algerian mints, Mentha spicata L. (M. spicata), Mentha pulegium L. and Mentha rotundifolia (L.) Huds by high performance thin layer chromatography (HPTLC)-densitometric method and screen the effects of these plant extracts on linoleic acid peroxidation. Methods: The analyses were performed on HPTLC silica gel 60 F254 plates with chloroform: acetone: formic acid (75:16.5:8.5, v/v) as the mobile phase....

  13. A comparative study on various spectrometries with thin layer chromatography for simultaneous analysis of drotaverine and nifuroxazide in capsules.

    Science.gov (United States)

    Ayad, Magda Mohammed; Youssef, Nadia Fayek; Abdellatif, Hisham Ezzat; Soliman, Suzan Mahmod

    2006-06-01

    Three spectrophotometric methods including Vierordt's method, derivative, ratio spectra derivative, and thin layer chromatography (TLC)-UV densitometric method were developed for simultaneous determination of drotaverine HCl (DRT) and nifuroxazide (NIF) in presence of its impurity, 4-hydroxybenzohydrazide (4-HBH). In Vierordt's method, (E(1 cm)(1%)) values were calculated at 227 and 368 nm in the zero-order spectra of DRT and NIF. By derivative spectrophotometry, the zero-crossing method, drotaverine HCl was determined using the second derivative at 245 nm and the third derivative at 238 nm, while nifuroxazide was determined using the first derivative at 399 nm and the second derivative at 411 nm. The ratio spectra derivative spectrophotometry is based on the measure of the amplitude at 459 nm for DRT and at 416 nm for NIF in the first derivative of the ratio spectra. Calibration graphs of the three spectrophotometric methods were plotted in the range 1-10 microg/ml of DRT and 2-20 microg/ml of NIF. TLC-UV densitometric method was achieved on silica gel plates using ethyl acetate : methanol : ammonia 33% (10 : 1 : 0.1 v/v/v) as the mobile phase. The Rf values were 0.74, 0.50, 0.30+/-0.01 for DRT, NIF and 4-HBH, respectively. On the fluorescent plates, the spots were located by fluorescence quenching and the densitometrical area were measured at 308 and 287 nm with linear range 0.2-4 microg/spot and 0.6-12 microg/spot for DRT and NIF, respectively. The proposed methods have been successfully applied to the commercial pharmaceutical formulation without any interference of excipients. Mean recoveries, relative standard deviations and the results of the proposed methods were compared with those obtained by applying the alternate methods. PMID:16755048

  14. Simultaneous Determination of Size and Quantification of Gold Nanoparticles by Direct Coupling Thin layer Chromatography with Catalyzed Luminol Chemiluminescence

    Science.gov (United States)

    Yan, Neng; Zhu, Zhenli; He, Dong; Jin, Lanlan; Zheng, Hongtao; Hu, Shenghong

    2016-04-01

    The increasing use of metal-based nanoparticle products has raised concerns in particular for the aquatic environment and thus the quantification of such nanomaterials released from products should be determined to assess their environmental risks. In this study, a simple, rapid and sensitive method for the determination of size and mass concentration of gold nanoparticles (AuNPs) in aqueous suspension was established by direct coupling of thin layer chromatography (TLC) with catalyzed luminol-H2O2 chemiluminescence (CL) detection. For this purpose, a moving stage was constructed to scan the chemiluminescence signal from TLC separated AuNPs. The proposed TLC-CL method allows the quantification of differently sized AuNPs (13 nm, 41 nm and 100 nm) contained in a mixture. Various experimental parameters affecting the characterization of AuNPs, such as the concentration of H2O2, the concentration and pH of the luminol solution, and the size of the spectrometer aperture were investigated. Under optimal conditions, the detection limits for AuNP size fractions of 13 nm, 41 nm and 100 nm were 38.4 μg L-1, 35.9 μg L-1 and 39.6 μg L-1, with repeatabilities (RSD, n = 7) of 7.3%, 6.9% and 8.1% respectively for 10 mg L-1 samples. The proposed method was successfully applied to the characterization of AuNP size and concentration in aqueous test samples.

  15. Simultaneous Determination of Size and Quantification of Gold Nanoparticles by Direct Coupling Thin layer Chromatography with Catalyzed Luminol Chemiluminescence

    Science.gov (United States)

    Yan, Neng; Zhu, Zhenli; He, Dong; Jin, Lanlan; Zheng, Hongtao; Hu, Shenghong

    2016-01-01

    The increasing use of metal-based nanoparticle products has raised concerns in particular for the aquatic environment and thus the quantification of such nanomaterials released from products should be determined to assess their environmental risks. In this study, a simple, rapid and sensitive method for the determination of size and mass concentration of gold nanoparticles (AuNPs) in aqueous suspension was established by direct coupling of thin layer chromatography (TLC) with catalyzed luminol-H2O2 chemiluminescence (CL) detection. For this purpose, a moving stage was constructed to scan the chemiluminescence signal from TLC separated AuNPs. The proposed TLC-CL method allows the quantification of differently sized AuNPs (13 nm, 41 nm and 100 nm) contained in a mixture. Various experimental parameters affecting the characterization of AuNPs, such as the concentration of H2O2, the concentration and pH of the luminol solution, and the size of the spectrometer aperture were investigated. Under optimal conditions, the detection limits for AuNP size fractions of 13 nm, 41 nm and 100 nm were 38.4 μg L−1, 35.9 μg L−1 and 39.6 μg L−1, with repeatabilities (RSD, n = 7) of 7.3%, 6.9% and 8.1% respectively for 10 mg L−1 samples. The proposed method was successfully applied to the characterization of AuNP size and concentration in aqueous test samples. PMID:27080702

  16. Quick identification of xanthine oxidase inhibitor and antioxidant from Erycibe obtusifolia by a drug discovery platform composed of multiple mass spectrometric platforms and thin-layer chromatography bioautography.

    Science.gov (United States)

    Chen, Zhiyong; Tao, Hongxun; Liao, Liping; Zhang, Zijia; Wang, Zhengtao

    2014-08-01

    As a final step of the purine metabolism process, xanthine oxidase catalyzes the oxidation of hypoxanthine and xanthine into uric acid. Our research has demonstrated that Erycibe obtusifolia has xanthine oxidase inhibitory properties. The purpose of this paper is to describe a new strategy based on a combination of multiple mass spectrometric platforms and thin-layer chromatography bioautography for effectively screening the xanthine oxidase inhibitory and antioxidant properties of E. obtusifolia. This strategy was accomplished through the following steps. (i) Separate the extract of E. obtusifolia into fractions by an autopurification system controlled by liquid chromatography with mass spectrometry. (ii) Determine the active fractions of E. obtusifolia by thin-layer chromatography bioautography. (iii) Identify the structure of the main active compounds with the information provided by direct analysis in real time mass spectrometry. (iv) Calculate the IC50 value of each compound against xanthine oxidase using high-performance liquid chromatography. Using the caulis of E. obtusifolia as the experimental material, seven target peaks were screened out as xanthine oxidase inhibitors or antioxidants. Our screening strategy allows for rapid analysis of small molecules with almost no sample preparation and can be completed within a week, making it a useful assay to identify unstable compounds and provide the empirical foundation for E. obtusifolia as a natural remedy for gout and oxidative-stress-related diseases.

  17. Quantification of Sunscreen Benzophenone-4 in Hair Shampoos by Hydrophilic Interactions Thin-Layer Chromatography/Densitometry or Derivative UV Spectrophotometry

    OpenAIRE

    Sobańska, Anna W.; Katarzyna Kałębasiak; Jarosław Pyzowski; Elżbieta Brzezińska

    2015-01-01

    Benzophenone-4 (BZ4) was separated from surfactants, dyes, preservatives, and other components of hair shampoos by thin-layer chromatography on silica gel 60 stationary phase, with ethyl acetate-ethanol-water-pH 6 phosphate buffer (15 : 7 : 5 : 1 v/v/v/v) as mobile phase. Densitometry scanning of chromatograms was performed at 285 nm. The densitometric calibration curve for BZ4 was nonlinear (second-degree polynomial), with R > 0.999. The limits of detection and quantification were ca. 0.03 a...

  18. Óleo essencial de limão no ensino da cromatografia em camada delgada Lime essential oil in the teaching of thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Rosaly S. Silva

    2009-01-01

    Full Text Available This paper describes a simple experiment employing the essential oil of limes which can be applied in undergraduate organic chemistry laboratory classes for the teaching of thin layer chromatography (TLC. The experiment consists in submit lime peel oil to TLC separation employing hexane and dichloromethane as the eluents and five different systems for visualization of the chromatogram. In one experiment it is possible to teach the different variables of the TLC technique. This experiment may also be performed following vapor distillation and liquid-liquid extraction technique in experimental classes.

  19. Simplified and rapid method for extraction of ergosterol from natural samples and detection with quantitative and semi-quantitative methods using thin-layer chromatography

    OpenAIRE

    Larsen, Cand.scient Thomas; Ravn, Senior scientist Helle; Axelsen, Senior Scientist Jørgen

    2004-01-01

    A new and simplified method for extraction of ergosterol (ergoste-5,7,22-trien-3-beta-ol) from fungi in soil and litter was developed using pre-soaking extraction and paraffin oil for recovery. Recoveries of ergosterol were in the range of 94 - 100% depending on the solvent to oil ratio. Extraction efficiencies equal to heat-assisted extraction treatments were obtained with pre-soaked extraction. Ergosterol was detected with thin-layer chromatography (TLC) using fluorodensitometry with a quan...

  20. Simultaneous Analysis of Losartan Potassium, Amlodipine Besylate, and Hydrochlorothiazide in Bulk and in Tablets by High-Performance Thin Layer Chromatography with UV-Absorption Densitometry

    OpenAIRE

    Karunanidhi Santhana Lakshmi; Sivasubramanian Lakshmi

    2012-01-01

    A Simple high-performance thin layer chromatography (HPTLC) method for separation and quantitative analysis of losartan potassium, amlodipine, and hydrochlorothiazide in bulk and in pharmaceutical formulations has been established and validated. After extraction with methanol, sample and standard solutions were applied to silica gel plates and developed with chloroform : methanol : acetone : formic acid 7.5 : 1.3 : 0.5 : 0.03 ( / / / ) as mobile phase. Zones were scanned densitometric...

  1. Comparison of thin-layer chromatography, spectrofluorimetry and bright greenish-yellow fluorescence test for aflatoxin detection in corn

    Directory of Open Access Journals (Sweden)

    Elisabete Yurie Sataque Ono

    2010-06-01

    Full Text Available In this study the bright greenish-yellow fluorescence test, widely used by the corn milling industry, was compared to the thin-layer chromatography (TLC and spectrofluorimetry methods for aflatoxin detection in 40 corn samples naturally contaminated by the Aspergillus section Flavi. According to the corn processing industry criteria, all the samples were adequate for human and animal consumption by the bright greenish-yellow fluorescence test, but TLC and spectrofluorimetry analysis detected aflatoxins above the maximum tolerated limit (20 µg/kg in 7 and 8 samples, respectively. Aflatoxins were detected in 16 (40% corn samples by TLC, with levels ranging from 4.0 to 54.0 µg/kg (mean 19.97 ± 15.97 µg/kg, and in 25 (62.5% samples by spectrofluorimetry, with levels ranging from 1.0 to 58.66 µg/kg (mean 17.14 ± 17.81 µg/kg. The results indicated a good correlation (ρ = 0.97 between TLC and spectrofluorimetry for aflatoxin determination in naturally contaminated corn. The bright greenish-yellow fluorescence test was simple and quick, but it showed 20% false-negative results, suggesting its use only as screening method for detecting the suspected lots of grains that should be tested further for aflatoxin by more sensitive methods.Neste trabalho a contagem de fluorescência luminosa amarelo-esverdeada, amplamente utilizada pela indústria de processamento de milho, foi comparada à cromatografia em camada delgada (CCD e espectrofluorimetria para detecção de aflatoxinas em 40 amostras de milho naturalmente contaminadas por Aspergillus section Flavi. De acordo com os critérios da indústria processadora de milho, todas as amostras estavam adequadas para o consumo humano e animal pela contagem de fluorescência luminosa amarelo-esverdeada (CFLAE, porém as análises por CCD e espectrofluorimetria detectaram aflatoxinas acima do limite máximo tolerado (20 µg/kg em 7 e 8 amostras, respectivamente. As aflatoxinas foram detectadas em 16 (40

  2. Marker based standardization of polyherbal formulation (SJT-DI-02 by high performance thin layer chromatography method

    Directory of Open Access Journals (Sweden)

    Bhakti J Ladva

    2014-01-01

    purity of the bands due to marker compounds in the sample extracts were confirmed by overlaying the absorption spectra recorded at start, middle and end position of the band in the sample tracks. After conforming all these things fingerprints were developed for all three formulations which will be act as authentification and quality control tool. Results: % w/w of asarones is 3.61, % w/w of marmelosin is 4.60, % w/w of gallic acid is 10.80 and % w/w of lupeol is 4.13.The method was validated in terms of linearity, precision, repeatability, limit of detection, limit of quantification and accuracy. In well-developed mobile phase system linearity was found to be in the range of 0.983-0.995, % recovery was found to be in the range of 97.48-99.63, % RSD for intraday and interday was found to be 0.13- 0.70 and 0.32 -1.41 and LOD and LOQ was found to be in the range of 0.15- 0.61 and 0.45 -1.83 microgram per ml. Conclusion: Thus High performance thin layer chromatography (HPTLC methods were developed and validated in terms of linearity, precision, repeatability, limit of detection, limit of quantification and accuracy. The methods were rapid, sensitive, reproducible and economical. It does not suffer any positive or negative interference due to common other component present in the formulation and would also serve as a tool for authentication of herbal products containing marmelosin, gallic acid, lupeol and asarones. Thus this work provides standardized and therapeutically active polyherbal formulations for the different ailments.

  3. Quantification of Sunscreen Benzophenone-4 in Hair Shampoos by Hydrophilic Interactions Thin-Layer Chromatography/Densitometry or Derivative UV Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Anna W. Sobańska

    2015-01-01

    Full Text Available Benzophenone-4 (BZ4 was separated from surfactants, dyes, preservatives, and other components of hair shampoos by thin-layer chromatography on silica gel 60 stationary phase, with ethyl acetate-ethanol-water-pH 6 phosphate buffer (15 : 7 : 5 : 1 v/v/v/v as mobile phase. Densitometry scanning of chromatograms was performed at 285 nm. The densitometric calibration curve for BZ4 was nonlinear (second-degree polynomial, with R>0.999. The limits of detection and quantification were ca. 0.03 and ca. 0.1 μg spot−1, respectively. The results obtained by HPTLC-densitometry were compared to those obtained by zero and 2nd derivative UV spectrophotometry. In the case of spectrophotometric methods, calibration curves were linear with R>0.9998. The chromatographic method was fully validated.

  4. Quantification of Sunscreen Benzophenone-4 in Hair Shampoos by Hydrophilic Interactions Thin-Layer Chromatography/Densitometry or Derivative UV Spectrophotometry.

    Science.gov (United States)

    Sobańska, Anna W; Kałębasiak, Katarzyna; Pyzowski, Jarosław; Brzezińska, Elżbieta

    2015-01-01

    Benzophenone-4 (BZ4) was separated from surfactants, dyes, preservatives, and other components of hair shampoos by thin-layer chromatography on silica gel 60 stationary phase, with ethyl acetate-ethanol-water-pH 6 phosphate buffer (15 : 7 : 5 : 1 v/v/v/v) as mobile phase. Densitometry scanning of chromatograms was performed at 285 nm. The densitometric calibration curve for BZ4 was nonlinear (second-degree polynomial), with R > 0.999. The limits of detection and quantification were ca. 0.03 and ca. 0.1 μg spot(-1), respectively. The results obtained by HPTLC-densitometry were compared to those obtained by zero and 2nd derivative UV spectrophotometry. In the case of spectrophotometric methods, calibration curves were linear with R > 0.9998. The chromatographic method was fully validated. PMID:25734022

  5. Phosphorolytic activity of Escherichia coli glycyl-tRNA synthetase towards its cognate aminoacyl adenylate detected by 31P-NMR spectroscopy and thin-layer chromatography

    DEFF Research Database (Denmark)

    Led, Jens Jørgen; Switon, Werner K.; Jensen, Kaj Frank

    1983-01-01

    The catalytic activity of highly purified Escherichia coli glycyl-tRNA synthetase has been studied by 31P-NMR spectroscopy and thin-layer chromatography on poly(ethyleneimine)-cellulose. It was found that this synthetase, besides the activation of its cognate amino acid and the syntheses of...... adenosine(5')tetraphospho(5')adenosine (Ap4A) and adenosine(5')triphospho(5')adenosine (Ap3A), also catalyzes the formation of ADP from inorganic phosphate and the enzyme-bound glycyl adenylate. Accordingly it was shown that E. coli glycyl-tRNA synthetase, in the presence of inorganic phosphate, glycine...... remaining catalytic activities of aminoacyl-tRNA synthetases is discussed, as well as the biological significance of the reaction....

  6. Antibacterial, antioxidant and cytotoxic studies of total saponin, alkaloid and sterols contents of decoction of Joshanda: identification of components through thin layer chromatography.

    Science.gov (United States)

    Khan, Haroon; Khan, Murad Ali; Abdullah

    2015-03-01

    The current study was aimed to assess antibacterial, antioxidant and cytotoxic activity of total saponin, alkaloid and sterol contents of Joshanda decoction followed by its constituent's analysis via thin layer chromatography (TLC). Saponins and alkaloids showed prominent antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and Klebsiella pneumoniae whereas sterols only against S. aureus. Saponin and alkaloid contents of 97 and 108 µg/ml, respectively, showed prominent free radical scavenging activity against 1,1-diphenyl-2-picrylhidrazyl, with mild cytotoxicity in brine shrimp cytotoxic test. Under ultraviolet light at 254 nm, TLC of total saponins showed eight different compounds, total sterols comprising three while total alkaloids two compounds of various polarities. It is concluded that the various contents of Joshanda decoction possess outstanding susceptibility against bacteria implicating primarily upper respiratory tract infections augmented by strong antioxidant activity. PMID:23235996

  7. Determination of neomycin in the form of neomycin derivative with dabsyl chloride by thin layer chromatography and densitometry.

    Science.gov (United States)

    Hubicka, Urszula; Zuromska-Witek, Barbara; Piotrowska, Joanna; Krzek, Jan

    2015-01-01

    A thin layer chromatographic-densitometric method has been developed for identification and quantitative determination of neomycin derivative with dabsyl chloride. The analysis of antibiotic was achieved on the silica gel TLC plates with fluorescent indicator with n-butanol--2-butanone--25% ammonia--water (10 : 6 : 2 : 2, v/v/v/v) as the mobile phase. The densitometric measurements were made at 460 nm. Under these conditions good separation of chosen aminoglycoside antibiotic from reagent used to make a complex was obtained. The method is characterized by high sensitivity, LOD from 0.1953 μg per band and LOQ from 0.5918 μg per band, wide linearity range from 0.5918 to 2.1960 μg per band for neomycin. The precision of the method was good; RSD varied from 1.17 to 2.05%. Satisfactory results of validation of the method were also confirmed by determination of selected antibiotic in pharmaceutical commercial preparation. The results obtained by TLC-densitometric method were compared with those obtained by spectrophotometric method.

  8. Quantitative Determination of L-DOPA in Seeds of Mucuna Pruriens Germplasm by High Performance Thin Layer Chromatography.

    Science.gov (United States)

    Raina, Archana P; Khatri, Renu

    2011-07-01

    Mucuna pruriens Linn. is an important medicinal plant used for treatment of Parkinson's disease and many others in ancient Indian medical system. L-DOPA extracted from seeds of Mucuna is a constituent of more than 200 indigenous drug formulations and is more effective as drug than the synthetic counterpart. A densitometric high performance thin-layer chromatographic (HPTLC) method was developed for quantification of L-DOPA content present in the seeds extract. The method involves separation of L-DOPA on precoated silica gel 60 GF(254) HPTLC plates using a solvent system of n-butanol-acetic-acid-water (4:1:1, v/v) as the mobile phase. Quantification was done at 280 nm using absorbance reflectance mode. Linearity was found in the concentration range of 100 to 1000 ng/spot with the correlation coefficient value of 0.9980. The method was validated for accuracy, precision and repeatability. Mean recovery was 100.89%. The LOD and LOQ for L-DOPA determination were found to be 3.41 ng/spot and 10.35 ng/spot respectively. The proposed HPTLC method was found to be precise, specific and accurate for quantitative determination of L-DOPA. It can be used for rapid screening of large germplasm collections of Mucuna pruriens for L-DOPA content. The method was used to study variation in fifteen accessions of Mucuna germplasm collected from different geographical regions. PMID:22707835

  9. Stability-indicating assay of repaglinide in bulk and optimized nanoemulsion by validated high performance thin layer chromatography technique

    Directory of Open Access Journals (Sweden)

    Juber Akhtar

    2013-01-01

    Full Text Available A sensitive, selective, precise and stability-indicating high-performance thin-layer chromatographic (HPTLC method for analysis of repaglinide both as a bulk drug and in nanoemulsion formulation was developed and validated. The method employed TLC aluminum plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of chloroform/methanol/ammonia/glacial acetic acid (7.5:1.5:0.9:0.1, v/v/v/v. This system was found to give compact spots for repaglinide (R f value of 0.38 ± 0.02. Repaglinide was subjected to acid and alkali hydrolysis, oxidation, photodegradation and dry heat treatment. Also, the degraded products were well separated from the pure drug. Densitometric analysis of repaglinide was carried out in the absorbance mode at 240 nm. The linear regression data for the calibration plots showed good linear relationship with r 2 = 0.998 ± 0.032 in the concentration range of 50-800 ng. The method was validated for precision, accuracy as recovery, robustness and specificity. The limits of detection and quantitation were 0.023 and 0.069 ng per spot, respectively. The drug undergoes degradation under acidic and basic conditions, oxidation and dry heat treatment. All the peaks of the degraded product were resolved from the standard drug with significantly different R f values. Statistical analysis proves that the method is reproducible and selective for the estimation of the said drug. As the method could effectively separate the drug from its degradation products, it can be employed as a stability-indicating one. Moreover, the proposed HPTLC method was utilized to investigate the degradation kinetics in 1M NaOH.

  10. Analysis of Bioactive Components of Oilseed Cakes by High-Performance Thin-Layer Chromatography-(Bioassay Combined with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Sue-Siang Teh

    2015-03-01

    Full Text Available Hemp, flax and canola seed cakes are byproducts of the plant oil extraction industry that have not received much attention in terms of their potential use for human food instead of animal feed. Thus, the bioactivity profiling of these oilseed cakes is of interest. For their effect-directed analysis, planar chromatography was combined with several (bioassays, namely 2,2-diphenyl-1-picrylhydrazyl scavenging, acetylcholine esterase inhibition, planar yeast estrogen screen, antimicrobial Bacillus subtilis and Aliivibrio fischeri assays. The streamlined high-performance thin-layer chromatography (HPTLC-bioassay method allowed the discovery of previously unknown bioactive compounds present in these oilseed cake extracts. In contrast to target analysis, the direct link to the effective compounds allowed comprehensive information with regard to selected effects. HPTLC-electrospray ionization-mass spectrometry via the elution-head based TLC-MS Interface was used for a first characterization of the unknown effective compounds. The demonstrated bioactivity profiling on the feed/food intake side may guide the isolation of active compounds for production of functional food or for justified motivation of functional feed/food supplements.

  11. Stability-indicating reversed-phase high-performance thin-layer chromatography/densitometry estimation of lafutidine in bulk and tablets

    Directory of Open Access Journals (Sweden)

    Prajapati Nitin D.

    2013-01-01

    Full Text Available Lafutidine (LTD is a histamine H2 receptor antagonist, with anti-ulcer and mucosal protective activity. A sensitive and selective stability-indicating reversed- phase high -performance thin-layer chromatography (RP-HPTLC/Densitometry method is suggested for the determination of LTD in the presence of its acid, alkaline, oxidative and dry heat degradation products. Stress testing of LTD was done according to the International Conference on Harmonization (ICH guidelines in order to validate the stability-indicating power of the analytical procedures. Stress testing demonstrated that LTD underwent acid, alkaline, oxidative and dry heat degradation; on the other hand, it showed stability towards neutral and photo degradation. Chromatography was performed on aluminum-backed silica gel 60 RP-18 F254 S plates with Methanol: Water: Triethylamine 8: 2: 0.5 (v/v as mobile phase. Densitometric scanning was performed at 276 nm. The system gave compact bands for LTD (Rf 0.67 ± 0.02. Linear regression analysis data for the calibration plots discovered a good linear relationship with r2 > 0.99 in the working concentration range 500 to 3000 ng per band. The limits of detection and quantification were 23.51 ng and 71.26 ng, respectively. The developed method can routinely be used for analysis of LTD in bulk and pharmaceutical formulations.

  12. Evaluation of thin-layer chromatography methods for quality control of commercial products containing Aesculus hippocastanum, Turnera diffusa, Matricaria recutita, Passiflora incarnata, and Tilia occidentalis.

    Science.gov (United States)

    Ramírez-Durón, Rosalba; Ceniceros-Almaguer, Lucía; Salazar-Aranda, Ricardo; Salazar-Cavazos, Ma de la Luz; Waksman de Torres, Noemi

    2007-01-01

    In Mexico, plant-derived products with health claims are sold as herbal dietary supplements, and there are no rules for their legal quality control. Aesculus hippocastanum, Turnera diffusa, Matricaria recutita, Passiflora incarnata, and Tilia occidentalis are some of the major commercial products obtained from plants used in this region. In this paper, we describe the effectiveness of thin-layer chromatography methods to provide for the quality control of several commercial products containing these plants. Standardized extracts were used. Of the 49 commercial products analyzed, only 32.65% matched the chromatographic characteristic of standardized extracts. A significant number of commercial products did not match their label, indicating a problem resulting from the lack of regulation for these products. The proposed methods are simple, sensitive, and specific and can be used for routine quality control of raw herbals and formulations of the tested plants. The results obtained show the need to develop simple and reliable analytical methods that can be performed in any laboratory for the purpose of quality control of dietary supplements or commercial herbal products sold in Mexico. PMID:17760328

  13. Qualitative and quantitative high performance thin layer chromatography analysis of Calendula officinalis using high resolution plate imaging and artificial neural network data modelling.

    Science.gov (United States)

    Agatonovic-Kustrin, S; Loescher, Christine M

    2013-10-10

    Calendula officinalis, commonly known Marigold, has been traditionally used for its anti-inflammatory effects. The aim of this study was to investigate the capacity of an artificial neural network (ANN) to analyse thin layer chromatography (TLC) chromatograms as fingerprint patterns for quantitative estimation of chlorogenic acid, caffeic acid and rutin in Calendula plant extracts. By applying samples with different weight ratios of marker compounds to the system, a database of chromatograms was constructed. A hundred and one signal intensities in each of the HPTLC chromatograms were correlated to the amounts of applied chlorogenic acid, caffeic acid, and rutin using an ANN. The developed ANN correlation was used to quantify the amounts of 3 marker compounds in calendula plant extracts. The minimum quantifiable level (MQL) of 610, 190 and 940 ng and the limit of detection (LD) of 183, 57 and 282 ng were established for chlorogenic, caffeic acid and rutin, respectively. A novel method for quality control of herbal products, based on HPTLC separation, high resolution digital plate imaging and ANN data analysis has been developed. The proposed method can be adopted for routine evaluation of the phytochemical variability in calendula extracts. PMID:24070490

  14. Construction of a supercritical fluid extraction (SFE equipment: validation using annatto and fennel and extract analysis by thin layer chromatography coupled to image

    Directory of Open Access Journals (Sweden)

    Júlio Cezar Flores JOHNER

    2016-01-01

    Full Text Available Abstract The present work describes setting up a laboratory unit for supercritical fluid extraction. In addition to its construction, a survey of cost was done to compare the cost of the homemade unit with that of commercial units. The equipment was validated using an extraction of annatto seeds’ oil, and the extraction and fractionation of fennel oil were used to validate the two separators; for both systems, the solvent was carbon dioxide. The chemical profiles of annatto and fennel extracts were assessed using thin layer chromatography; the images of the chromatographic plates were processed using the free ImageJ software. The cost survey showed that the homemade equipment has a very low cost (~US$ 16,000 compared to commercial equipment. The extraction curves of annatto were similar to those obtained in the literature (yield of 3.8% oil. The separators were validated, producing both a 2.5% fraction of fennel seed extract rich in essential oils and another extract fraction composed mainly of oleoresins. The ImageJ software proved to be a low-cost tool for obtaining an initial evaluation of the chemical profile of the extracts.

  15. Determination of guanine and adenine by high-performance liquid chromatography with a self-fabricated wall-jet/thin-layer electrochemical detector at a glassy carbon electrode.

    Science.gov (United States)

    Zhou, Yaping; Yan, Hongling; Xie, Qingji; Yao, Shouzhuo

    2015-03-01

    A sensitive wall-jet/thin-layer amperometric electrochemical detector (ECD) coupled to high-performance liquid chromatography (HPLC) was developed for simultaneous determination of guanine (G) and adenine (A). The analytes were detected at a glassy carbon electrode (GCE) and the HPLC-ECD calibration curves showed good linearity (R(2)>0.997) under optimized conditions. Limits of detection for G and A are 0.6 nM and 1.4 nM (S/N=3), respectively, which are lower than those obtained with an UV-vis detector and a commercial electrochemical detector. We have successfully applied this HPLC-ECD to assess the contents of G and A in hydrochloric acid-digested calf thymus double-stranded DNA. In addition, we compared in detail the analysis of G and A by cyclic voltammetry (CV) and by the HPLC-ECD system on both bare GCE and electroreduced graphene oxide (ERGO) modified GCE. We found that the adsorption of G and A on the electrode surfaces can vary their anodic CV peaks and the competitive adsorption of G and A on the limited sites of the electrode surfaces can cause crosstalk effects on their anodic CV peak signals, but the HPLC-ECD system is insensitive to such electrode-adsorption and can give more reliable analytical results. PMID:25618679

  16. Application of thin-layer chromatography with fluorescence scanning densitometry for analysing saturates in heavy liquids derived from co-pyrolysis of biomass and plastics

    Energy Technology Data Exchange (ETDEWEB)

    Cebolla, V.L. [Consejo Superior de Investigaciones Cientificas (CSIC), Instituto de Carboquimica, Zaragoza (Spain); Matt, M. [Institute of Chemistry and Chemical Technology, Krasnoyarsk (Russian Federation). Siberian Branch of Russian Academy of Sciences; Membrado, L. [Universite de Metz, Saint-Avold (FR). Laboratoire de Chimie et Applications] [and others

    2002-01-01

    Two alternative methods, based on Thin-Layer Chromatography (TLC) with Fluorescence Scanning Densitometry have been developed for characterization of heavy liquids from copyrolysis of different kinds of biomass and plastics in autoclaves under inert atmosphere. A conventional TLC system, which includes a vertical developing tank, and a High Performance TLC (HPTLC) system, with a horizontal developing chamber and the use of HPTLC plates, have been used. The analytical method involves in both cases the measurement of two chromatograms per sample: the first, on a silica gel berberine-impregnated plate, for detection of saturates using the phenomenon of berberine-induced fluorescence; and the second, on a silica gel plate, for detection of aromatic-polars and polars, by native fluorescence. Although the HPTLC system is more sensitive and faster, both techniques represent an improvement with regard to current methods for analyzing these kinds of products. However their application depends on the particular solubility of each sample and on its slope of the fluorescent response-sample load regression. (orig.)

  17. Rapid Identification and Comparison of Compounds with Antioxidant Activity in Coreopsis tinctoria Herbal Tea by High-Performance Thin-Layer Chromatography Coupled with DPPH Bioautography and Densitometry.

    Science.gov (United States)

    Lam, Shing-Chung; Lam, Sio-Fong; Zhao, Jing; Li, Shao-Ping

    2016-09-01

    A simple and efficient method based on high-performance thin-layer chromatography coupled with 2,2-diphenyl-1-picrylhydrazyl (DPPH) bioautography (HPTLC-DPPH) was established for the screening and comparison of antioxidants in different parts of Coreopsis tinctoria herbal tea from different origins and other related herbal tea materials, which used Chrysanthemum morifolium cv. "Gongju" and "Hangju" in this study. Scanning densitometry after DPPH derivatization was applied for the determination of antioxidant capacities of isolated compounds in each sample. It is considered that ethanol extracts of C. tinctoria had stronger antioxidant activity and more characteristic bands than those of 2 compared samples, C. morifolium cv. "Gongju" and "Hangju." Chemometric analysis results showed that the combination of hierarchical clustering analysis and principal component analysis based on determined antioxidant capacities could be used for the discrimination of different parts of C. tinctoria and C. morifolium. Results showed that 7 compounds made up the major contributions of antioxidant activity in C. tinctoria, including okanin, isookanin, marein, flavanomarein, 5,7,3',5'-tetrahydroxyflavanone-7-O-glucoside, 3,5-dicaffeoylquinic acid, and chlorogenic acid. Therefore, 7 compounds were identified as major antioxidant biomarkers for quality control of C. tinctoria. Results demonstrated that the established method could be applied for the identification of C. tinctoria, and were beneficial for the bioactivity-based quality control of C. tinctoria.

  18. Algerian mint species: high performance thin layer chromatography quantitative determination of rosmarinic acid and in vitro inhibitory effects on linoleic acid peroxidation

    Directory of Open Access Journals (Sweden)

    Brahmi Fatiha

    2014-12-01

    Full Text Available Objective: To determine the quantitative paremeters of rosmarinic acid in Algerian mints, Mentha spicata L. (M. spicata, Mentha pulegium L. and Mentha rotundifolia (L. Huds by high performance thin layer chromatography (HPTLC-densitometric method and screen the effects of these plant extracts on linoleic acid peroxidation. Methods: The analyses were performed on HPTLC silica gel 60 F254 plates with chloroform: acetone: formic acid (75:16.5:8.5, v/v as the mobile phase. Rosmarinic acid was determined in UV at 365 nm and fluorescence at λexc 325 nm with a 550 nm filter, respectively. The effects of plants extracts on linoleic acid peroxidation were measured by an indirect in vitro colorimetric method. Results: Chromatographic resolution permitted reliable quantification in both measurement modes and calibration curves were linear in a range of 150-1 000 ng/spot. M. spicata was found to contain significantly higher concentrations of rosmarinic acid. The densitometric quantification allowed the analysis of many samples in a short time with reasonable precision (total precision for Mentha spp extracts, 5.1% and 5.8% for UV and fluorescence detection, respectively. The HPTLC data, allied to assays of linoleic acid peroxidation prevention, suggested the potential of M. spicata (52% Trolox® equivalents as a natural source for inhibitors of lipid peroxidation. Conclusions: Densitometry can be used for routine determination and quality control of rosmarinic acid in herbal and formulations containing Mentha species.

  19. Algerian mint species:high performance thin layer chromatography quantitative determination of rosmarinic acid and in vitro inhibitory effects on linoleic acid peroxidation

    Institute of Scientific and Technical Information of China (English)

    Brahmi Fatiha; Madani Khodir; Stvigny Caroline; Chibane Mohamed; Duez Pierre

    2014-01-01

    Objective: To determine the quantitative paremeters of rosmarinic acid in Algerian mints,Mentha spicata L. (M. spicata), Mentha pulegium L. and Mentha rotundifolia (L.) Huds by high performance thin layer chromatography (HPTLC)-densitometric method and screen the effects of these plant extracts on linoleic acid peroxidation.Methods:The analyses were performed on HPTLC silica gel 60 F254 plates with chloroform:acetone: formic acid (75:16.5:8.5, v/v) as the mobile phase. Rosmarinic acid was determined in UV at 365 nm and fluorescence at λexc 325 nm with a 550 nm filter, respectively. The effects of plants extracts on linoleic acid peroxidation were measured by an indirect in vitro colorimetric method.Results:Chromatographic resolution permitted reliable quantification in both measurement modes and calibration curves were linear in a range of 150-1000 ng/spot. M. spicata was found to contain significantly higher concentrations of rosmarinic acid. The densitometric quantification allowed the analysis of many samples in a short time with reasonable precision (total precision for Mentha spp extracts, 5.1% and 5.8% for UV and fluorescence detection, respectively). The HPTLC data, allied to assays of linoleic acid peroxidation prevention, suggested the potential of M. spicata (52% Trolox®equivalents) as a natural source for inhibitors of lipid peroxidation.Conclusions:Densitometry can be used for routine determination and quality control of rosmarinic acid in herbal and formulations containing Mentha species.

  20. Application of 2-Trichloromethylbenzimidazole in Analytical Chemistry: A Highly Selective Chromogenic Reagent for Thin-Layer Chromatography and Some Other Analytical Uses

    Directory of Open Access Journals (Sweden)

    Leszek Konopski

    2012-01-01

    Full Text Available 2-Trichloromethylbenzimidazole (TCMB was used as a chromogenic reagent in organic or inorganic analysis, mainly in thin-layer chromatography (TLC. In reactions of TCMB with some heteroaromatic nitrogen containing compounds, such as azines, azoles and benzazoles, a formation of high colored products occurred. For azines, the chromogenic reaction was highly regioselective, since the both adjacent α-positions versus the nitrogen atom(s must not be substituted. A TLC method of detection was developed. Thirty azines, azoles, and benzazoles were detected at the detection limit 10 ng to 1 μg. This method was also applied for detection of heteroaromatic pesticides, and the attempts to construct active and passive dosimeters for nicotine were made. In a prechromatographic reaction of aromatic o-diamines with methyl trichloroacetimidate, TCMB or its derivatives were formed in situ. Followed by TLC and visualization in pyridine vapors, this procedure was applied for detection of o-phenylenediamine derivatives. The reaction product of TCMB and pyridine (LI Complex was identified and fully characterized. Two different reaction mechanisms: with electron deficient basic heteroaromatic compounds, like pyridine, and with more acidic compounds, for example, pyrrole, were discussed. In aqueous solutions, the LI Complex may be also used as a new indicator for complexometric, adsorption and acid-base titration of inorganic compounds.

  1. Thin layer chromatography-densitometric determination of some non-sedating antihistamines in combination with pseudoephedrine or acetaminophen in synthetic mixtures and in pharmaceutical formulations.

    Science.gov (United States)

    El-Kommos, Michael E; El-Gizawy, Samia M; Atia, Noha N; Hosny, Noha M

    2014-03-01

    The combination of certain non-sedating antihistamines (NSA) such as fexofenadine (FXD), ketotifen (KET) and loratadine (LOR) with pseudoephedrine (PSE) or acetaminophen (ACE) is widely used in the treatment of allergic rhinitis, conjunctivitis and chronic urticaria. A rapid, simple, selective and precise densitometric method was developed and validated for simultaneous estimation of six synthetic binary mixtures and their pharmaceutical dosage forms. The method employed thin layer chromatography aluminum plates precoated with silica gel G 60 F254 as the stationary phase. The mobile phases chosen for development gave compact bands for the mixtures FXD-PSE (I), KET-PSE (II), LOR-PSE (III), FXD-ACE (IV), KET-ACE (V) and LOR-ACE (VI) [Retardation factor (Rf ) values were (0.20, 0.32), (0.69, 0.34), (0.79, 0.13), (0.36, 0.70), (0.51, 0.30) and (0.76, 0.26), respectively]. Spectrodensitometric scanning integration was performed at 217, 218, 218, 233, 272 and 251 nm for the mixtures I-VI, respectively. The linear regression data for the calibration plots showed an excellent linear relationship. The method was validated for precision, accuracy, robustness and recovery. Limits of detection and quantitation were calculated. Statistical analysis proved that the method is reproducible and selective for the simultaneous estimation of these binary mixtures.

  2. Using electrospray-assisted laser desorption/ionization mass spectrometry to characterize organic compounds separated on thin-layer chromatography plates.

    Science.gov (United States)

    Lin, Shu-Yao; Huang, Min-Zong; Chang, Hui-Chiu; Shiea, Jentaie

    2007-11-15

    Electrospray-assisted laser desorption/ionization (ELDI), an ionization method that combines laser desorption and electrospray ionization (ESI), can be used under ambient conditions to characterize organic compounds (including FD&C dyes, amines, extracts of a drug tablet) separated in the central track on a thin-layer chromatography (TLC) plate coated with either reversed-phase C18 particles or normal-phase silica gel. After drying, the TLC plate was placed on an acrylic sample holder set in front of the sampling skimmer of an ion trap mass analyzer. The chemicals at the center of the TLC plate were analyzed by pushing the sample holder into the path of a laser beam with a syringe pump. The molecules in the sample spot were desorbed by continuously irradiating the surface of the TLC plate with a pulsed nitrogen laser. Then, the desorbed sample molecules entered an ESI plume where they were ionized through the reactions with the charged species (including protons, hydronium ions and their cluster ions, solvent ions, and charged droplets) generated by electrospraying a methanol/water solution. MS/MS analyses were also performed to further characterize the analytes. The detection limit of TLC/ELDI/MS is approximately 10(-6) M. This was evaluated by using FD&C red dye as the standard. A linear relationship was found for the calibration curve with the concentration of FD&C red dye ranged from 10(-3) to 10(-6) M. PMID:17929897

  3. Thin-layer chromatography combined with MALDI-TOF-MS and 31P-NMR to study possible selective bindings of phospholipids to silica gel.

    Science.gov (United States)

    Teuber, Kristin; Riemer, Thomas; Schiller, Jürgen

    2010-12-01

    High-performance thin-layer chromatography (HPTLC) is a highly established separation method in the field of lipid and (particularly) phospholipid (PL) research. HPTLC is not only used to identify certain lipids in a mixture but also to isolate lipids (preparative TLC). To do this, the lipids are separated and subsequently re-eluted from the silica gel. Unfortunately, it is not yet known whether all PLs are eluted to the same extent or whether some lipids bind selectively to the silica gel. It is also not known whether differences in the fatty acyl compositions affect the affinities to the stationary phase. We have tried to clarify these questions by using a readily available extract from hen egg yolk as a selected example of a lipid mixture. After separation, the complete lanes or selected spots were eluted from the silica gel and investigated by a combination of MALDI-TOF MS and (31)P NMR spectroscopy. The data obtained were compared with the composition of the total extract (without HPTLC). Although there were significant, solvent-dependent losses in the amount of each lipid, the relative composition of the mixture remained constant; there were also only very slight changes in the fatty acyl compositions of the individual PL classes. Therefore, lipid isolation by TLC may be used without any risk of major sample alterations. PMID:20694807

  4. Simultaneous Analysis of Losartan Potassium, Amlodipine Besylate, and Hydrochlorothiazide in Bulk and in Tablets by High-Performance Thin Layer Chromatography with UV-Absorption Densitometry

    Directory of Open Access Journals (Sweden)

    Karunanidhi Santhana Lakshmi

    2012-01-01

    Full Text Available A Simple high-performance thin layer chromatography (HPTLC method for separation and quantitative analysis of losartan potassium, amlodipine, and hydrochlorothiazide in bulk and in pharmaceutical formulations has been established and validated. After extraction with methanol, sample and standard solutions were applied to silica gel plates and developed with chloroform : methanol : acetone : formic acid 7.5 : 1.3 : 0.5 : 0.03 (/// as mobile phase. Zones were scanned densitometrically at 254 nm. The values of amlodipine besylate, hydrochlorothiazide, and losartan potassium were 0.35, 0.57, and 0.74, respectively. Calibration plots were linear in the ranges 500–3000 ng per spot for losartan potassium, amlodipine and hydrochlorothiazide, the correlation coefficients, r, were 0.998, 0.998, and 0.999, respectively. The suitability of this method for quantitative determination of these compounds was by validation in accordance with the requirements of pharmaceutical regulatory standards. The method can be used for routine analysis of these drugs in bulk and in formulation.

  5. Detection and Estimation of alpha-Amyrin, beta-Sitosterol, Lupeol, and n-Triacontane in Two Medicinal Plants by High Performance Thin Layer Chromatography

    Directory of Open Access Journals (Sweden)

    Saikat S. Mallick

    2014-01-01

    Full Text Available A normal phase high performance thin layer chromatography (HPTLC method has been developed and validated for simultaneous estimation of four components, namely, alpha-amyrin, beta-sitosterol, lupeol, and n-triacontane from two medicinally important plants, Leptadenia reticulata Wight & Arn. and Pluchea lanceolata (DC. CB. Clarke. In Ayurveda, both plants have been reported to possess immunomodulatory activity. Chromatographic separation of the four components from the methanolic extracts of whole plant powders of Leptadenia reticulata Wight & Arn. and Pluchea lanceolata (DC. CB. Clarke. was performed on TLC aluminium plates precoated with silica gel 60F254 using a suitable mobile phase. The densitometric scanning was done after derivatization at λ = 580 nm for α-amyrin, β-sitosterol, and lupeol, and at 366 nm for n-triacontane. The developed HPTLC method has been validated and used for simultaneous quantitation of the four components from the methanolic extracts of whole plant powders of Leptadenia reticulata Wight & Arn. and Pluchea lanceolata (DC. CB. Clarke. The developed HPTLC method is simple, rapid, and precise and can be used for routine quality control.

  6. Linear modeling of the soil-water partition coefficient normalized to organic carbon content by reversed-phase thin-layer chromatography.

    Science.gov (United States)

    Andrić, Filip; Šegan, Sandra; Dramićanin, Aleksandra; Majstorović, Helena; Milojković-Opsenica, Dušanka

    2016-08-01

    Soil-water partition coefficient normalized to the organic carbon content (KOC) is one of the crucial properties influencing the fate of organic compounds in the environment. Chromatographic methods are well established alternative for direct sorption techniques used for KOC determination. The present work proposes reversed-phase thin-layer chromatography (RP-TLC) as a simpler, yet equally accurate method as officially recommended HPLC technique. Several TLC systems were studied including octadecyl-(RP18) and cyano-(CN) modified silica layers in combination with methanol-water and acetonitrile-water mixtures as mobile phases. In total 50 compounds of different molecular shape, size, and various ability to establish specific interactions were selected (phenols, beznodiazepines, triazine herbicides, and polyaromatic hydrocarbons). Calibration set of 29 compounds with known logKOC values determined by sorption experiments was used to build simple univariate calibrations, Principal Component Regression (PCR) and Partial Least Squares (PLS) models between logKOC and TLC retention parameters. Models exhibit good statistical performance, indicating that CN-layers contribute better to logKOC modeling than RP18-silica. The most promising TLC methods, officially recommended HPLC method, and four in silico estimation approaches have been compared by non-parametric Sum of Ranking Differences approach (SRD). The best estimations of logKOC values were achieved by simple univariate calibration of TLC retention data involving CN-silica layers and moderate content of methanol (40-50%v/v). They were ranked far well compared to the officially recommended HPLC method which was ranked in the middle. The worst estimates have been obtained from in silico computations based on octanol-water partition coefficient. Linear Solvation Energy Relationship study revealed that increased polarity of CN-layers over RP18 in combination with methanol-water mixtures is the key to better modeling of

  7. Quantitative determination of seven chemical constituents and chemo-type differentiation of chamomiles using high-performance thin-layer chromatography

    Science.gov (United States)

    Matricaria recutita L. (German Chamomile), Anthemis nobilis L. (Roman Chamomile) and Chrysanthemum morifolium Ramat are commonly used chamomiles. High performance thin layer chromatographic (HPTLC) method was developed for estimation of six flavonoids (rutin, luteolin-7-O-ß-glucoside, chamaemeloside...

  8. Development and Validation of High Performance Thin-Layer Chromatography and Derivative Spectrophotometry methods for determination of Diazepam and Propranolol Hydrochloride in Combined Dosage Form

    Directory of Open Access Journals (Sweden)

    Bhadani Shweta

    2013-03-01

    Full Text Available The manuscript describes validated high performance thin layer chromatography (HPTLC and first derivative UV spectrophotometric methods for the estimation of diazepam (DZP and propranolol hydrochloride (PRO in combined dosage form. The HPTLC separation was achieved on an aluminium-backed layer of silica gel 60F254 using mobile phase ethylacetate-methanol-toluene-triethylamine (1.0 + 3.0 + 6.0 + 0.1, v/v/v/v. Quantification was achieved with UV detection at 235 nm over the concentration range 25 – 250 ng/spot and 200 – 2000 ng/spot for DZP and PRO respectively, with mean recovery of 100.3 ± 0.54 and 100.2 ± 0.35 % for DZP and PRO, respectively by HPTLC method. Derivative spectrophotometric method was based on the estimation of both the drugs at their respective zero crossing point (ZCP. The first-order derivative spectra were obtained at N = 1 (scaling factor, Δλ = 2.0 nm, and the determinations were made at 248 nm (ZCP of PRO for DZP and 242 nm (ZCP of DZP for PRO over the concentration range of 2.5–30 μg/mL for both DZP and PRO with mean recovery of 100.2 ± 0.49 and 100.1 ± 0.13 % for DZP and PRO, respectively by first derivative UV spectrophotometric method. These methods were found to be simple, sensitive, accurate, precise, reproducible and economical and applicable for the simultaneous determination of DZP and PRO in combined dosage form.

  9. High performance thin layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) for the qualitative and quantitative analysis of Calendula officinalis-advantages and limitations.

    Science.gov (United States)

    Loescher, Christine M; Morton, David W; Razic, Slavica; Agatonovic-Kustrin, Snezana

    2014-09-01

    Chromatography techniques such as HPTLC and HPLC are commonly used to produce a chemical fingerprint of a plant to allow identification and quantify the main constituents within the plant. The aims of this study were to compare HPTLC and HPLC, for qualitative and quantitative analysis of the major constituents of Calendula officinalis and to investigate the effect of different extraction techniques on the C. officinalis extract composition from different parts of the plant. The results found HPTLC to be effective for qualitative analysis, however, HPLC was found to be more accurate for quantitative analysis. A combination of the two methods may be useful in a quality control setting as it would allow rapid qualitative analysis of herbal material while maintaining accurate quantification of extract composition.

  10. High performance thin layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) for the qualitative and quantitative analysis of Calendula officinalis-advantages and limitations.

    Science.gov (United States)

    Loescher, Christine M; Morton, David W; Razic, Slavica; Agatonovic-Kustrin, Snezana

    2014-09-01

    Chromatography techniques such as HPTLC and HPLC are commonly used to produce a chemical fingerprint of a plant to allow identification and quantify the main constituents within the plant. The aims of this study were to compare HPTLC and HPLC, for qualitative and quantitative analysis of the major constituents of Calendula officinalis and to investigate the effect of different extraction techniques on the C. officinalis extract composition from different parts of the plant. The results found HPTLC to be effective for qualitative analysis, however, HPLC was found to be more accurate for quantitative analysis. A combination of the two methods may be useful in a quality control setting as it would allow rapid qualitative analysis of herbal material while maintaining accurate quantification of extract composition. PMID:24880991

  11. Anti-inflammatory activity and qualitative analysis of different extracts of Maytenus obscura (A. Rich.) Cuf. by high performance thin layer chromatography method

    Institute of Scientific and Technical Information of China (English)

    Mohamed F. Alajmi; Perwez Alam

    2014-01-01

    Objective: To perform aqueous ethanol soluble fraction (AESF) and dichloromethane extract of aerial parts of Maytenus obscura (A. Rich.) Cuf. using high performance thin layer chromatography (HPTLC) and to test anti-inflammatory activity of these extracts.Methods:HPTLC studies were carried out using CAMAG HPTLC system equipped with Linomat IV applicator, TLC scanner 3, Reprostar 3, CAMAG ADC 2 and WIN CATS-4 software were used. The anti-inflammatory activity was tested by injecting different groups of rats (6 each) with formalin in hind paw and measuring the edema volume before and 1 h later formalin injection. Control group received saline i.p. The extracts treatment was injected i.p. in doses of 100 and 200 mg/kg 1 h before formalin administration. Indomethacin (30 mg/kg) was used as standard.Results:The results of preliminary phytochemical studies confirmed the presence of protein, lipid, carbohydrate, phenol, flavonoid, saponin, triterpenoid, alkaloid and anthraquinone in both extracts. Chromatography was performed on glass-backed silica gel 60 F254 HPTLC plates with the green solvents toluene: ethyacetate: glacial acetic acid (5:3:0.2, v/v/v) as mobile phase. HPTLC finger printing of AESF revealed major eight peaks with Rf values in the range of 0.28 to 0.80 and the dichloromethane revealed major 11 peaks with Rf values in the range of 0.12 to 0.76. The purity of sample was confirmed by comparing the absorption spectra at start, middle and end position of the band. Treatment of rats (i.p.) with AESF and dichloromethane in doses of 100 and 200 mg/kg inhibited singnificantly (P<0.05, n=6) formalin-induced inflammation by 50%, 55.9%, 45.5%, and 51.4%, respectively.Conclusions:HPTLC finger printing of AESF and dichloromethane of Maytenus obscura revealed eight major spots for alcoholic extracts and nine major spots for dichloromethane extracts. These HPTLC profiles may be of great usefulness in the quality control of herbal products containing these extracts. The

  12. Children better powder identified by thin layer chromatography%小儿吐泻宁散剂薄层层析鉴别

    Institute of Scientific and Technical Information of China (English)

    刘秋伟; 姜亚玲; 李占灵

    2016-01-01

    小儿吐泻宁散剂作为芳香化湿药,主要含广藿香、甘草、厚朴、陈皮、半夏等药材。实验通过薄层层析色谱法来鉴别这五种药材的有效成分进而来鉴别小儿吐泻宁散剂。通过制备五种药物主要成分的供试液、阴性、阳性对照液,在经过严格的薄层色谱鉴别后绘制了完善的色谱图。通过直观的色谱图观察,得到了满意的实验结果。成功地鉴别了小儿吐泻宁散剂中的五种主药。%As aromatization wet medicine mainly containing patchouli,liquorice,magnolia bark and herbs such as dried tangerine or orange peel.This experiment made by thin layer chromatography to identify the active ingredients of the me-dicinal materials to identify four children in children better dispersing agent.By making four drugs main composition of the fluid,feminine positive control under test,and the purchase of four main components:the autumn lee alcohol,ammonium glycyrrhetatehonokiol,Beta sitosterol.After strict TLC was used to prepare the perfect chromatogram.Through intuitive chromatogram observation,the satisfactory experimental results were obtained,and successfully identify the pediatric chil-dren better dispersing agent`s five ingredients.

  13. Identification of Ginkgo biloba supplements adulteration using high performance thin layer chromatography and ultra high performance liquid chromatography-diode array detector-quadrupole time of flight-mass spectrometry.

    Science.gov (United States)

    Avula, Bharathi; Sagi, Satyanarayanaraju; Gafner, Stefan; Upton, Roy; Wang, Yan-Hong; Wang, Mei; Khan, Ikhlas A

    2015-10-01

    Ginkgo biloba is one of the most widely sold herbal supplements and medicines in the world. Its popularity stems from having a positive effect on memory and the circulatory system in clinical studies. As ginkgo popularity increased, non-proprietary extracts were introduced claiming to have a similar phytochemical profile as the clinically tested extracts. The standardized commercial extracts of G. biloba leaf used in ginkgo supplements contain not less than 6% sesquiterpene lactones and 24% flavonol glycosides. While sesquiterpene lactones are unique constituents of ginkgo leaf, the flavonol glycosides are found in many other botanical extracts. Being a high value botanical, low quality ginkgo extracts may be subjected to adulteration with flavonoids to meet the requirement of 24% flavonol glycosides. Chemical analysis by ultra high performance liquid chromatography-mass spectrometry revealed that adulteration of ginkgo leaf extracts in many of these products is common, the naturally flavonol glycoside-rich extract being spiked with pure flavonoids or extracts made from another flavonoid-rich material, such as the fruit/flower of Japanese sophora (Styphnolobium japonicum), which also contains the isoflavone genistein. Recently, genistein has been proposed as an analytical marker for the detection of adulteration of ginkgo extracts with S. japonicum. This study confirms that botanically authenticated G. biloba leaf and extracts made therefrom do not contain genistein, and the presence of which even in trace amounts is suggestive of adulteration. In addition to the mass spectrometric approach, a high performance thin layer chromatography method was developed as a fast and economic method for chemical fingerprint analysis of ginkgo samples.

  14. 三种金花茶叶的薄层色谱鉴别研究%Studies on Idetification of three varieties Camellia byThin-Layer Chromatography

    Institute of Scientific and Technical Information of China (English)

    梁霄; 莫建光; 刘布鸣; 黄艳; 高微; 黎凯群; 黎奕良

    2014-01-01

    Objective To establish a method for identification of Camellia by Thin-Layer Chromatography (TLC).Methods The specific compouds,oleanolic acid,rutin and ginsenosides Rg1 were studied by TLC in three different Camellia species.Results These three kinds of ingredients were all separated very well by the Ligroin-acetoacetate -acetone (7∶2∶1 ),Acetoacetate -methanol-aquaefer-formic acid (9∶2∶1∶0.1 ),Chloroform-acetoacetate-methanol-aquaefer (3∶8∶4.4∶1.6 ),and under the same condi-tions,the spots of oleanolic acid,rutin and ginsenosides Rg1 were significantly in different three varieties of Camellia.Conclusion This method was simple ,quick,and can better control the quality of the Camellia.%目的:建立金花茶叶的薄层色谱鉴别方法。方法:采用薄层色谱法分别鉴别金花茶叶中的齐墩果酸、芦丁和人参皂苷Rg1等化学成分。结果:齐墩果酸、芦丁和人参皂苷Rg1分别在以石油醚-乙酸乙酯-丙酮(7∶2∶1)、乙酸乙酯-甲醇-水-甲酸(9∶2∶1∶0.1)和氯仿-乙酸乙酯-甲醇-水(3∶8∶4.4∶1.6)为展开剂的条件下获得理想分离,且在同一点样量和展开条件下,三个金花茶品种中的齐墩果酸、芦丁、人参皂苷Rg1斑点均有明显差异。结论:该方法简便、快速,可更好地控制金花茶叶的药材质量。

  15. 野生大豆皂苷的提取与薄层色谱分析%Extraction and Thin Layer Chromatography of Saponins from Wild Soybean

    Institute of Scientific and Technical Information of China (English)

    张倩; 刘代成

    2011-01-01

    皂苷具有多种药理作用,对野生大豆中各类皂苷的定量分析是研究野生大豆皂苷药理作用的基础.利用索氏提取器以甲醇热回流提取野生大豆中的皂苷,结合理化反应进行鉴别,以齐墩果酸作为对照品进行薄层层析,通过薄层扫描测定皂苷含量.结果表明:野生大豆皂苷1~5μg范围内线性关系良好,平均回收率为98.98%,RSD为0.41%,薄层层析斑点清晰且分离良好,计算得总皂苷在野生大豆脱脂粕中的含量为1.91%,远高于在栽培大豆脱脂粕中的含量.该方法简便准确,结果稳定,可用于野生大豆皂苷的分析.%Saponins have many pharmacological actions. The determination of wild soybean saponins contents is the basis of the pharmacological experiments. In this experiment,wild soybean saponins were extracted by Soxhlet extractor with hot circulatory methanol, identified by physical-chemical reactions and the thin layer chromatography(TLC)with the oleanic acid taken as reference standard,and then the TLC scanner was used to determine the content of the saponins. The linear range of wild soybean saponins was from 1 to 5 μg;the average recovery was 98.98% with RSD of 0.41%. The TLC identification was distinct and the spots were clear. The content of saponins in defatted wild soybean was 1.91% .which was significantly higher than that in defatted cultivated soybean. The method is simple and accurate with stable outcomes, and suitable for analysis of wild soybean saponins.

  16. Study on Corydalis Yanhusuo Rhubarb Curcuma and Dragon's Blood in Pain -Restraining Medicinal Membrane by Thin -layer Chromatography%克痛药膜中元胡大黄姜黄血竭的薄层色谱研究

    Institute of Scientific and Technical Information of China (English)

    谢浩洋; 丁关生

    2012-01-01

    目的:研究克痛药膜中的元胡、血竭、姜黄、大黄4味中药的薄层色谱.方法:采用薄层色谱法,在硅胶G薄层板上,以环己烷-丙酮(8∶2)为展开剂,鉴别元胡;以石油醚( 60 ~ 90℃) -乙醚(3∶2)为展开剂,鉴别大黄;以三氯甲烷-甲醇-甲酸(96∶4∶0.7)为展开剂为展开剂,鉴别姜黄;以三氯甲烷-甲醇(19∶1)为展开剂,鉴别血竭.结果:依据正文所述方法,薄层展开后,色谱斑点显色清晰,分离效果好,与对照药材显色一致.结论:依据正文所述方法,针对元胡、血竭、姜黄、大黄4味中药,其薄层色谱图的检出成分消除了其它成分的干扰,专属性强,重现性好,方法简便,可以作为该制剂质量控制的检测标准.%Objective: To research corydalis yanhusuo,rhubarb,curcuma and dragons blood in pain - restraining medici-nal membrane by thin - layer chromatography. Methods: Adopting the thin - layer chromatography, on the thin layer of the silicon G, identified corydalis yanhusuo using cyclohexane - acetone (8 : 2 ) as the developing agent; identified rhubarb using petroleum ether(60 ~90℃ ) -aether(3 : 2)as the developing agent;identified curcuma using chloroform -methanol -meth-anoic acid(96 :4 : 0.7) as the developing agent; identified dragons blood using chlorqform -methanol (19 : l)as the develo-ping agent. Results :According to the related method,after the thin layer expanded,every main fleck was clearly colored, well disparted and have the same color with the respective contrast medicinal materialss main flecks. Conclusions: Accord-ing to the related method,the thin - layer chromatography clearly showed the component of corydalis yanhusuo,rhubarb,cur-cuma and dragons blood which were distinctly detected without the interference of other elements. The related method was specific, repeatable, simple, and could be taken as the standard to control the quality of this preparation.

  17. Determinação de fármacos diuréticos em associação por cromatografia em camada delgada e espectrofotometria Determination of diuretic drugs by thin layer chromatography and spectrophotometry

    Directory of Open Access Journals (Sweden)

    Dênia Mendes de Sousa Valladão

    2008-01-01

    Full Text Available A rapid, sensitive and reliable thin-layer chromatography/spectrophotometry screening procedure was developed for quantitative determination of diuretics associated in pharmaceutical dosage forms. The chromatographic method employed microcrystalline cellulose and butanol : acetic acid : water (4:1:1 or amilic alcohol : ammonium hydroxide 25% (9:1 as mobile phases and detection by U.V. light. The drugs were extracted using a simple procedure and were quantified by U.V. spectrophotometry. Results varied from 97.5 to 102.5% and are similar to those obtained by conventional methods. This method of quantification of diuretics is promising for quality control of drugs.

  18. Determination of furanochromones and pyranocoumarins in drugs and Ammi visnaga fruits by combined solid-phase extraction-high-performance liquid chromatography and thin-layer chromatography-high-performance liquid chromatography.

    Science.gov (United States)

    Zgórka, G; Dragan, T; Głowniak, K; Basiura, E

    1998-02-27

    A new, simple and rapid solid-phase extraction method for the determination of furanochromones and pyranocoumarins in Ammi visnaga L. fruits and pharmaceuticals by reversed-phase high-performance liquid chromatography (RP-HPLC) was developed. The isolation of compounds examined was carried out on octadecyl BakerBond SPE columns using various concentrations of methanol, acetonitrile and tetrahydrofuran in water. High and reproducible recoveries were obtained. To compare the results of quantitative analysis a preparative TLC procedure was also elaborated and carried out.

  19. Gold nanoparticles grafted modified silica gel as a new stationary phase for separation and determination of steroid hormones by thin layer chromatography

    Directory of Open Access Journals (Sweden)

    Mitra Amoli-Diva

    2015-06-01

    Full Text Available A new thin layer chromatographic layer using gold nanoparticles grafted 3-triethoxysilyl propylamine modified silica gel (Au NPs-APTS modified silica gel was developed as a stationary phase for separation and determination of two steroid hormones, namely progesterone and testosterone. Acetone–n-hexane 25:75 (v/v was used as the mobile phase, and the results were compared with those obtained using plain (i.e., unmodified silica gel plates. Some chromatographic parameters used for separation of the two steroids on an Au NPs-APTS modified silica gel plate as well as on a plain silica gel plate, including ΔRF, separation factor (α, and resolution (RS, were evaluated and compared. The reproducibility of RF values was also determined by analysis of the two steroids in 7 consecutive days on both plates. Validity of the method was investigated, and a wide linear range of 1–200 ng per spot, and low detection limits of 0.16 ng and 0.13 ng per spot, low quantification limits of 0.51 ng and 0.40 ng per spot, and good precision (expressed as percent relative standard deviation lower than 3.1% and 2.7% were obtained for progesterone and testosterone, respectively. As the results revealed, the proposed method is rapid and sensitive, and it is applicable to separation and determination of progesterone and testosterone in biological matrices such as urine samples.

  20. 薄层色谱法检测海州常山桐树叶中肾上腺素的含量%Identification and quantification of adrenaline from the leaves of Clerodendrum phlomidis using thin-layer chromatography

    Institute of Scientific and Technical Information of China (English)

    Muthu Kumaradoss Mohan Maruga Raja; Ruchi Sureshbhai Patel; Shri Hari Mishra

    2011-01-01

    @@ In the Ayurvedic, Siddha and other medical systems of India, products derived from herbs,used either as active ingredients or as adjuvants,hold paramount importance as alternative medi-cines.However, their standardization poses a great challenge.Correct identification of these drugs is often problematic in both their complete form as well as in powder form, since these medicinal plants are known by a variety of vernacular names and frequently many medicinal plants share the same name.Comparative thin-layer chromatography (co-TLC) with chemical or biological marker compounds can be used to standardize raw materials.Moreover, due to its simplicity, accuracy, cost effectiveness and rapidity, TLC is often used as an alternative to other chromatographic tech-niques for quantifying plant products.

  1. Determination of alpha-solanine and alpha-chaconine in potatoes by high-performance thin-layer chromatography/densitometry.

    Science.gov (United States)

    Bodart, P; Kabengera, C; Noirfalise, A; Hubert, P; Angenot, L

    2000-01-01

    A high-performance thin-layer chromatographic (HPTLC) method was used to determine the glycoalkaloids alpha-solanine and alpha-chaconine in potatoes. Alpha-solanine and alpha-chaconine are extracted from dehydrated potatoes with boiling methanol-acetic acid (95 + 5, v/v). The analytes are separated on a Silica Gel 60 F254 HPTLC plate by a saturated mixture of dichloromethane-methanol-water-concentrated ammonium hydroxide (70 + 30 + 4 + 0.4, v/v), which is used for vertical development of the plate up to a distance of 85 mm. For visualization, the plate is dipped 3 times into a modified Carr-Price reagent, 20% (w/v) antimony(III) chloride in acetic acid-dichloromethane (1 + 3, v/v), and subsequently heated on a hot plate at 105 degrees C for 5 min. The glycoalkaloids all appear as red chromatographic zones on a colorless background. Densitometric quantification is performed at 507 nm by reflectance scanning. After determination of the appropriate response function, the proposed method was validated. Good results with respect to linearity, accuracy, and precision were obtained in the concentration range studied.

  2. Thin-layer chromatographic study of the phenolics of the Pleurocladula species (Hepaticae)

    OpenAIRE

    Maria Krzakowa

    2014-01-01

    Phenolic compounds in Pleurocladula albescens (Hook.) Grolle and Pleurocladuia islandica (Nees) Grolle were studied by two-dimensional thin-layer chromatography. Consistent differences between both taxa were found.

  3. Polarity-adjustable reversed phase ultrathin-layer chromatography.

    Science.gov (United States)

    Hall, J Z; Taschuk, M T; Brett, M J

    2012-11-30

    Reversed phase thin layer chromatography (TLC) or high performance thin layer chromatography (HPTLC) plates modified with C18, C8 or C2 to provide the silica-gel stationary phase with different polarities are available on the market, however, reversed phase plates with tunable polarity have not been reported. Given the limited variety of reversed phase plates, mobile phase composition optimization is necessary to obtain better separation of analytes with similar characteristics, which is often a time consuming step. We present polarity-adjustable reversed phase ultrathin-layer chromatography (UTLC) plates, which simplifies the mobile phase screening process and greatly expands the selection of reversed phase plates. The plates were fabricated on glass substrates with SiO(2) nanopillars deposited using the glancing angle deposition (GLAD) technique. SiO(2) nanopillars were functionalized with octadecyltrichlorosilane to generate a super hydrophobic stationary phase. Unlike commercial silica-gel based stationary phases, the isolated nanopillar architecture presented here exposes a high surface area to post-fabrication surface treatments. In our work, an O(2) plasma treatment at different powers, pressures and exposure times was used to shorten the silane carbon chain and introduce COOH groups to the surface, producing plates with finely tunable polarities. Separation of a model dye mixture of Sudan blue and Sudan IV confirmed the tuning of surface polarities by measurement of retention behavior changes. The dye elution order reversed as a result of the change in surface polarity. When the same plasma treatment process was tested on commercial reversed phase plates, separation behavior did not change because the disordered and tortuous silica gel restricts the accessible surface area. Plasma treatment of GLAD structures with highly accessible surfaces improved control over interfacial properties, producing better reverse phase separations. PMID:23116804

  4. Use of thin layer chromatography for the determination of radiochemical purity of radiopharmaceuticals in nuclear medicine services of Paraiba and Rio Grande do Norte, Brazil; Utilizacao da cromatografia em camada delgada para determinacao da pureza radioquimica de radiofarmacos em servicos de medicina nuclear da Paraiba e Rio Grande do Norte, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, W.G.; Santos, P.A.L.; Lima, F.R.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Programa de Pos-Graduacao em Tecnologia Energetica; Lima, F.F., E-mail: wellington.gandrade@gmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2012-07-01

    The paper chromatography and the thin layer chromatography are separation techniques in which the radioactive components migrate because of their affinity with the eluent (mobile phase) or stationary phase, respectively. In radiopharmaceuticals labeled with {sup 99m}Tc, besides its own radiopharmaceutical, {sup 99m}TcO{sup 4-} free and TcO{sub 2} can be identified and quantified. The evaluation of radiochemical purity of radiopharmaceuticals is essential to produce images free of artifacts as well as avoid unnecessary absorbed dose to the patient. Once they are managed in humans it is important and necessary that they undergo to strict quality control. Because of this, ANVISA in its 'Resolucao da Diretoria Colegiada (RDC) 38 of June 4th, 2008 states the obligation of performing a minimum of tests in nuclear medicine services routine prior to human administration. This work evaluated, by the method of thin layer chromatography (TLC), radiochemical purity, determined the pH of the radiopharmaceutical DEXTRAN- 500, DMSA, DTPA, PHYTATE, MDP, MIBI and Sn-Col used in nuclear medicine services in the states of Paraiba and Rio Grande do Norte - Brazil. The results show that the use of thin layer chromatography (TLC) as a standard method in routine of nuclear medicine services is possible, because it provides important data for the evaluation of radiochemical purity, allowing the exclusion of a radiopharmaceutical poorly marked. (author)

  5. Suitability of thin-layer chromatography-flame ionization detection with regard to quantitative characterization of different fossil fuel products. II. Calibration methods concerning quantitative hydrocarbon-group type analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vela, J.; Membrado, L.; Cebolla, V.L.; Ferrando, A.C. [CSIC, Zaragoza (Spain). Inst. de Carboquimica, Dept. de Procesos Quimicos

    1998-10-01

    Time-consuming external standard-based calibration methods are usually performed for hydrocarbon group type analysis (HGTA) of fossil fuels, regardless of the instrumental chromatographic technique. HGTA of a broad variety of coal and petroleum products was performed using a modern thin-layer chromatography-flame ionization detection (TLC-FID) system and a rapid method based on internal normalization. Repeatability, linear intervals, and sample load ranges for quantitative application of this method are given, namely a heavy oil and its derived hydrocracked products, raw and chemically-modified petroleum asphaltenes, a coal-tar pitch, several coal extracts, and coal hydroliquefaction products. Results from external standard calibration and a normalization method (both obtained by TLC-FID) are in agreement, and they are validated using TLC-ultraviolet scanning. The use of the latter demonstrates that TLC-FID can also be applied to products such as coal extracts and hydroliquefaction products, despite these products being more volatile than petroleum asphaltenes or heavy oils. 14 refs., 3 figs., 5 tabs.

  6. Cromatografia em camada delgada para o diagnóstico da intoxicação por aldicarb ("chumbinho" em cães e gatos Thin-layer chromatography for aldicarb poisoning diagnosis in dogs and cats

    Directory of Open Access Journals (Sweden)

    F.G. Xavier

    2007-10-01

    Full Text Available Avaliou-se a cromatografia em camada delgada (CCD como método de diagnóstico toxicológico para os casos de intoxicação por aldicarb em cães e gatos, utilizando-se 50 amostras de conteúdo gástrico obtidas durante a necropsia e 50 amostras de alimentos utilizados como iscas para intoxicar criminalmente os animais. Todas as amostras resultaram positivas para o aldicarb, mostrando ser a CCD uma técnica qualitativa eficiente, rápida e de baixo custo, com uso potencial na toxicologia veterinária forense.The present study concerns about the identification of aldicarb residues using thin-layer chromatography (TLC in 50 samples of gastric content obtained from the necropsy of dogs and cats and 50 samples of foods suspected of being used as baits. All samples resulted positive for aldicarb showing that the TLC is an efficient, fast and not expensive qualitative method for the detection of aldicarb, being useful for this purpose in the forensic veterinary toxicology.

  7. The deconjugation ability of bacteria isolated from the jejunal fluids in the blind loop syndrome with high sup 14 CO sub 2 excretion. Using the breath analysis technique and thin-layer chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Shindo, K.; Yamazaki, R.; Mizuno, T.; Shionoiri, H.; Sugiyama, M. (Yokohama City Univ. School of Medicine, (Japan))

    1989-01-01

    Five patients with blind loop syndrome (Billroth II) were examined by measuring {sup 14}CO{sub 2} specific activity of expired breath samples taken at intervals after a meal containing glycine-1-{sup 14}C cholate. The 5 patients tested showed a marked increase of {sup 14}CO{sub 2} specific activity. Furthermore, the ability of deconjugation of bacteria isolated from the jejunal fluids in the efferent loop of these patients was tested by thin-layer chromatography. The bacterial species identified from the samples were as follows: enterococcus, Lactobacillus buchneri, L. bifidus, L. brevis, Eubacterium lentum, Bacteroides vulgaricus, B. filamentosum, Corynebacterium granulosum, Escherichia coli, Staphylococcus epidermidis, and Aerobacter aerogenes. These species of bacteria, except E. coli and A. aerogenes, showed the deconjugation ability by which conjugated bile acids in ox gall was hydrolyzed. Administration of chloramphenicol to the 5 patients reduced {sup 14}CO{sub 2} specific activity significantly. On the other hand, 9 healthy men who were tested showed a flat curve, and 8 of the 9 had no growth of bacteria isolated from the jejunal fluids. The remaining healthy man showed an over growth of E. coli and Pseudomonas aeruginosa, but the species did not have the ability of deconjugation.

  8. Thin Layer Drying Kinetics of of Roselle

    OpenAIRE

    Suherman; B. Fajar; H. Satriadi; O. Yuariski; R.S. Nugroho; A. Shobib

    2012-01-01

    This study was performed to determine the most appropriate thin layer drying model and the effective moisture diffusivity of Roselle (Hibiscus sabdariffa). Roselle with an Initial Moisture Content (IMC) of 85%, on wet basis (wb) was dried in a conventional tray dryer at temperatures of 40, 50 and 60ºC. The drying data were fitted to eleven thin layer models and a thin layer model for the roselle calyx was developed by regressing the coefficients of the best fit model. The newton model was mos...

  9. Physicochemical properties of silica gel coated with a thin layer of polyaniline (PANI) and its application in non-suppressed ion chromatography.

    Science.gov (United States)

    Sowa, Ireneusz; Kocjan, Ryszard; Wójciak-Kosior, Magdalena; Swieboda, Ryszard; Zajdel, Dominika; Hajnos, Mieczysław

    2013-10-15

    Physicochemical properties of a new sorbent and its potential application in non-suppressed ion chromatography (IC) have been investigated. The sorbent was obtained in a process of covering silica gel particles with a film of polyaniline (PANI). The properties of silica modified with polyaniline such as particle size, porosity, average quantity of polyaniline covering carrier and density of sorbent were determined. In our study the following methods were used: microscopic analysis, laser diffraction technique, combustion analysis, mercury porosimetry and helium pycnometry. Column with the newly obtained packing was used for the separation of inorganic anions. Optimized chromatographic system was successfully employed for analysis of iodide and bromide in selected pharmaceutical products (Bochnia salt and Iwonicz salt) applied in chronic respiratory disease. Analysis was carried out using 0.1M solution of HCl in mixture of methanol/water (50:50v/v) as a mobile phase; the flow rate was 0.3 mL min(-1), temperature was 24°C and λ=210 nm. Validation parameters such as correlation coefficient, RSD values, recovery, detection and quantification limits were found to be satisfactory.

  10. Delamination of Compressed Thin Layers at Corners

    DEFF Research Database (Denmark)

    Sørensen, Kim Dalsten; Jensen, Henrik Myhre; Clausen, Johan

    2008-01-01

    An analysis of delamination for a thin elastic layer under compression, attached to a substrate at a corner is carried out. The analysis is performed by combining results from interface fracture mechanics and the theory of thin shells. In contrast with earlier results for delamination on a flat...

  11. Separation of sturgeon bile by thin layer of chromatography silica%薄层层析分离鲟鱼胆汁

    Institute of Scientific and Technical Information of China (English)

    陈金芳; 郭振林; 龚世伟; 陈蓉; 陈启明

    2012-01-01

    To effectively transform useless sturgeon bile into medicinal products with high added-value, a process concerning medicinal resource of separating sturgeon bile was proposed. Effective ingredients of sturgeon bile were separated by the developing solvent with different solvent systems. Solvent systems of unary, binary and ternary were used as developing solvents in experiment. The influence of separating the sturgeon bile was investigated by the developing solvent with different solvent systems. The results show that the unary solvents such as toluene and chloroform have a fine separability, the binary solvents of chloroform/ethanol, chloroform/methanol, and petroleum ether/acetone have a better separation effect, the ternary solvents of petroleum ether/acetone/toluene (3:1:1, volume ratio) and chloroform/methanol/toluene (5:1:1, volume ratio) have obvious separation effects. Therefore, we selected Chloroform/methanol (10:1, volume ratio) as an appropriate solvent system to follow-up separation of sturgeon bile by column chromatography.%为了综合利用鲟鱼加工下脚料,提高鲟鱼附加值和中药产业临床应用价值,提出了采用不同的溶剂系统作展开剂分离鲟鱼胆汁的有效成分的方法.实验过程中,分别以单元溶剂、二元溶剂以及三元溶剂体系作展开剂,考察了不同体系的展开剂对鲟鱼胆汁分离效果的影响.结果表明:单元溶剂中甲苯和氯仿分离效果好,二元溶剂体系中氯仿/乙醇、氯仿/甲醇、石油醚/丙酮以及三元溶剂体系中石油醚/丙酮/甲苯(3:1:1,体积比)、氯仿/甲醇/甲苯(5:1:1,体积比)分离效果较佳.筛选出二元溶剂氯仿/甲醇(10:1,体积比)最适宜后续的柱层析分离鲟鱼胆汁.

  12. 橘叶黄酮类成分的研究与薄层色谱鉴别%Studies on Flavonoids of Folium Citri Reticulatae and Identification by Thin Layer Chromatography

    Institute of Scientific and Technical Information of China (English)

    汪金玉; 帅欧; 林励; 庄满贤; 苏昭仑; 黄振

    2011-01-01

    [目的]分离、鉴定橘叶中黄酮类成分,并以所得到的黄酮类成分为对照品建立其薄层色谱鉴别方法,为橘叶的质量控制提供科学依据.[方法]以硅胶柱层析法分离橘叶黄酮类成分,采用核磁共振法进行结构鉴定,并以所得黄酮类成分为对照品,对橘叶药材进行硅胶薄层色谱鉴别.[结果]从橘叶中分离得到川陈皮素、5-去甲川陈皮素、橘红素、异橙黄酮,所建立的薄层色谱图斑点清晰,分离度良好.[结论]首次从橘叶中分离得到川陈皮素等4种黄酮类化合物,新建立的橘叶薄层鉴别方法薄层行为良好,适用于橘叶的鉴别.%Objective To separate and identify the flavonoids from Folium Citri Reticulatae, and to establish a thin layer chromatogram ( TLC ) method for the identification of Folium Citri Reticulatae with flavonoids as the reference substance. Methods We separated flavonoids of Folium Citri Reticulatae by silica gel column chromatography and identified their structure by nuclear magnetic resonance (NMR) and mass spectrometry (MS). With the obtained flavonoids as reference substance, we identified the medicinal material of Folium Citri Reticulatae by silica gel TLC. Results Nobiletin, 5-demethyl nobiletin, tangeretin, and isosinensetin were isolated from Folium Citri Reticulatae successfully. The established thin layer chromatogram spots were clear, with good separation.Conclusion Flavonoids such as nobiletin, 5-demethyl nobiletin, tangeretin, and isosinensetin have been isolated from Folium Citri Reticulatae for the first time. The established TLC method is efficient and suitable for the identification of Folium Citri Reticulatae.

  13. Determinação de aflatoxina B1 em pimenta (Piper nigrum L.) e orégano (Origanum vulgare L.) por cromatografia em camada delgada e densitometria Determination of aflatoxin B1 (Piper nigrum L.) and oregano (Origanum vulgare L.) by thin-layer chromatography and densitometry

    OpenAIRE

    Guilherme Prado; Marize Silva de Oliveira; Ana Paula Aprígio Moreira; Adriana de Souza Lima; Robson de Assis Souza; Matheus do Carmo Alves

    2008-01-01

    An analytical study based on extraction with methanol-water, immunoaffinity cleanup and separation, identification and quantification of aflatoxin B1 by thin-layer chromatography,in ground black and white pepper and oregano was carried out. Validation of the applied methodology was done through accuracy and precision studies. Recoveries of aflatoxin B1 and relative standard deviations, from spice samples spiked at levels from 4.86 to 97.70 µg/kg, were, respectively, higher than 72% and lower ...

  14. Delamination of Compressed Thin Layers at Corners

    DEFF Research Database (Denmark)

    Sørensen, Kim D.; Jensen, Henrik Myhre; Clausen, Johan

    2008-01-01

    An analysis of delamination for a thin elastic layer under compression, attached to a substrate at a corner is carried out. The analysis is performed by combining results from interface fracture mechanics and the theory of thin shells. In contrast with earlier results for delamination on a flat...... results for the fracture mechanical properties have been obtained, and these are applied in a study of the effect of contacting crack faces. Special attention has been given to analyse conditions under which steady state propagation of buckling driven delamination takes place. Keywords: Delamination, Thin...... layers, Fracture mechanics, Crack closure, Steady state crack propagation....

  15. Study of Thin Layer Chromatography Identification on Epimedium, Drynaria Rhizome and the Like of Huocao Zhuanggu Mixture%藿草壮骨合剂中淫羊藿、骨碎补等薄层色谱鉴别方法的研究

    Institute of Scientific and Technical Information of China (English)

    韦国麟; 刘华珍; 蔡杰; 温坚

    2015-01-01

    Objective:To improve the quality standard on raw material and finished product of Huocao Zhuanggu mixture, and provide safe and effec-tive Chinese medicine preparation clinically. Methods:Thin layer chromatography was used to identify the epimedium, radix rehmanniae praeparata and drynaria rhizome. Results: Thin layer chromatography could identify the characteristic spots of epimedium, radix rehmanniae praeparata and drynaria rhizome, and spots were clear without interference. Conclusion:Thin layer chromatography is simple and convenient, with reliable results and strong specificity as well as good repeatability and durability, providing reference for the quality control of Huocao Zhuanggu mixture.%目的:提高霍草壮骨合剂原药材与成品的质量标准,为临床提供安全有效的中药制剂.方法:采用薄层色谱法鉴别方中淫羊藿、熟地黄、骨碎补.结果:薄层色谱鉴别淫羊藿、骨碎补、熟地黄的特征斑点,且斑点清晰无干扰.结论:薄层色谱法方法简便,结果可靠,专属性强,重现性、耐用性好,可为藿草壮骨合剂的质量控制提供参考.

  16. Study on Thin-layer Chromatography Separation and Anti-bacterial Activity of Mentha spicata Linn Essential Oil%留兰香挥发油的薄层分离及抗菌活性研究

    Institute of Scientific and Technical Information of China (English)

    张晓伟; 李青雨; 王德国; 石倩倩; 王佳华

    2011-01-01

    [目的]对留兰香挥发油的组分及抗菌活性进行研究.[方法]采用薄层色谱法对留兰香挥发油的组分进行初步分离,采用扩散法及紫外可见分光光度法对留兰香挥发油的抗菌活性进行测定.[结果]以石油醚:乙酸乙酯(V:V=6:1)为层析液时,留兰香挥发油的分离效果最好,分离出4种主要物质;留兰香精油对3种试验菌株的抑菌性为枯草芽孢杆菌(Bacillus subtdis)>金黄色葡萄球菌(Staphylococcus aureus)>大肠杆菌(Escherichia coli);对枯草芽孢杆菌、金黄色葡萄球菌、大肠杆菌的最低抑菌浓度(MIC)分别为:0.50,1.00,3.50μl/ml.[结论]留兰香挥发油具有抑菌作用,这为综合开发留兰香提供了理论基础.%[ Objective ] To study the composition and the anti-bacterial activity of volatile oil from Mentha spicata Linn. [ Method ] Using thin-layer chromatography ( TLC ), the compositions of essential oil from Mentha spicata Linn were separated. The inhibitory activity was determined by diffusion method combining with UV spectrophotometry. [ Result] Using petroleum ether- ethyl acetate ( V: V =6:1 ) as chromatography liquid, the essential oil from Mentha spicata Linn was best in separation and four components were obtained. The inhibitory effect of volatile oil from Mentha spicata Linn to three test strains was determined to be Bacillus subtilis > Staphylococcus aureus > Escherichia coli with MIC value of 0.50, 1.00 and 3.50 ul/ml, respectively. [ Conclusion ] The volatile oil from Mentha spicata Linn had anti-bacterial effect, which provided theoretical basis for comprehensive development of Mentha spicata Linn.

  17. Multi-Instrument Characterization of the Surfaces and Materials in Microfabricated, Carbon Nanotube-Templated Thin Layer Chromatography Plates. An Analogy to ‘The Blind Men and the Elephant’

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, David S.; Kanyal, Supriya S.; Madaan, Nitesh; Hancock, Jared M.; Dadson, Andrew; Vail, Michael A.; Vanfleet, Richard; Shutthanandan, V.; Zhu, Zihua; Engelhard, Mark H.; Linford, Matthew R.

    2013-08-08

    Herein we apply a suite of surface/materials analytical tools to characterize some of the materials created in the production of microfabricated thin layer chromatography plates. Techniques used include X-ray photoelectron spectroscopy (XPS), valence band spectroscopy, static time-of-flight secondary ion spectrometry (ToF-SIMS) in both positive and negative ion modes, Rutherford backscattering spectroscopy (RBS), and helium ion microscopy (HIM). Materials characterized include: the Si(100) substrate with native oxide: Si/SiO2, alumina (35 nm) deposited as a diffusion barrier on the Si/SiO2: Si/SiO2/Al2O3, iron (6 nm) thermally evaporated on the Al2O3: Si/SiO2/Al2O3/Fe, the iron film annealed in H2 to make Fe catalyst nanoparticles: Si/SiO2/Al2O3/Fe(NP), and carbon nanotubes (CNTs) grown from the Fe nanoparticles: Si/SiO2/Al2O3/Fe(NP)/CNT. The Fe thin films and nanoparticles are found in an oxidized state. Some of the analyses of the CNTs/CNT forests reported appear to be unique: the CNT forest appears to exhibit an interesting ‘channeling’ phenomenon by RBS, we observe an odd-even effect in the ToF-SIMS spectra of Cn- species for n = 1 – 6, with ions at even n showing greater intensity than the neighboring signals, and ions with n ≥ 6 showing a steady decrease in intensity, and valence band characterization of CNTs using X-radiation is reported. The information obtained from the combination of the different analytical tools provides a more complete understanding of our materials than a single technique, which is analogous to the story of ‘The Blind Men and the Elephant’. (Of course there is increasing emphasis on the use of multiple characterization tools in surface and materials analysis.) The raw XPS and ToF-SIMS spectra from this study will be submitted to Surface Science Spectra for archiving.

  18. Ocorrência de aflatoxinas em arroz consumido por militares do Exército Brasileiro por cromatografia em camada delgada e cromatografia líquida de alta eficiência Incidence of aflatoxins in rice to be consumed by militaries in the brazilian army by thin layer chromatography and high performance liquid chromatography methods

    Directory of Open Access Journals (Sweden)

    Jader Oliveira da Silva

    2008-08-01

    November 2003 to febuary 2004 when the incidence of aflatoxins B1, B2, G1 and G2 was measured by thin layer chromatography (TLC and high performance liquid chromatography (HPLC methods. This work had the aim of comparing the thin layer chromatography and high performance liquid chromatography techniques and contributed for the quality control of the foods to be consumed by militaries of the Brazilian army, concerning the control of the aflatoxins levels. From a total of 30 samples were tested performed by tlc, no aflatoxin was detected. From 26 samples, analysed trough high performance liquid chromatography, 6 (23, 07% presented positive results for aflatoxin B1 with 0, 54 2, 04 µg/kg and, 1 (3, 84% presented a positive result for aflatoxins B2 with 1, 84 µg/kg.

  19. [Thin-layer chromatographic determination of coumarin derivatives].

    Science.gov (United States)

    Tsvetkova, Ts M

    1977-01-01

    Described is a thin-layer chromatography method for the demonstration and identification of the cumarin derivatives cumaphos and warfarin. Tested were five solvents and six developers. Best results were obtained by means of Silica gel plates, the toluol-aceton solvent (85:15), and the developer of a diazosalt 0.4% in an alcohol 20% sodiumhydroxide. Warfarin and cumaphos are demonstrated with the appearance of yellow, resp. orange spots on a white background, the RF values being 0.37 and 0.85, and sensitivity as regards warfarin 0.5 microgram and cumaphos 0.2 microgram. PMID:898648

  20. Thin Layer Drying Models in Food Systems

    OpenAIRE

    Demirkol, Naciye Kutlu, Aslı İşçi, Özge Şakıyan

    2015-01-01

    Drying is one of the most complicated food processes which include simultaneous heat and masstransfer. It is generally defined as the removal of moisture from food. The microbial and enzyme activity indry food products are quite low due to reduced water activity. Therefore, drying is widely preferred inlong term storage of foods. The drying mechanism, common drying techniques used in industry andthin layer drying models were summarized in this review. Thin layer drying models can be classifie...

  1. Perovskite thin films via atomic layer deposition.

    Science.gov (United States)

    Sutherland, Brandon R; Hoogland, Sjoerd; Adachi, Michael M; Kanjanaboos, Pongsakorn; Wong, Chris T O; McDowell, Jeffrey J; Xu, Jixian; Voznyy, Oleksandr; Ning, Zhijun; Houtepen, Arjan J; Sargent, Edward H

    2015-01-01

    A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3 NH3 PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm(-1) .

  2. Perovskite Thin Films via Atomic Layer Deposition

    KAUST Repository

    Sutherland, Brandon R.

    2014-10-30

    © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. (Graph Presented) A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3NH3PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm-1.

  3. Thin Layer Chromatography-High Performance Liquid Chromatographic Method for the Determination of Sudan Red in Food%薄层层析-高效液相色谱法测定食品中苏丹红

    Institute of Scientific and Technical Information of China (English)

    李春香; 黄坚; 马慧雪; 张祥

    2011-01-01

    The new method of determining banned additives in the food such as Sudan red Ⅰ and Ⅱ was established with thin layer chromatography(TLC) and high performance liquid chromatography(HPLC) two methods combined.Sudan red and impurities can be separated by silica gel plate.Under the condition of chromatography in setting,the concentration in the 0.1~20.0 μg/mL range,the peak areas(Y) and concentration(X) present good linear relationship,Sudan red Ⅰ,Ⅱ regression equations Y1=-18785+138962X,Y2=-2623+131432X.Correlation coefficient R1=0.9997,R2=0.9998.Its application of determing the Sudan red Ⅰ and Ⅱ in chili powder,chili oil,and tomato sauce was studied,and got the detection limit of 0.024 μg/g,0.027 μg/g,respectively.%建立了薄层层析-高效液相色谱联合技术测定食品中违禁添加物苏丹红Ⅰ、Ⅱ的新方法。采用硅胶板将苏丹红与杂质分离,在设定的色谱条件下测得浓度在0.1~20.0μg/mL范围内,峰面积(Y)与浓度(X)呈良好线性关系,苏丹红Ⅰ、的回归方程为Y1=-18785+138962X,Y2=-2623+131432X,相关系数R1=0.9997,R2=0.9998。将该法应用于辣椒粉、辣椒油、番茄酱等中的苏丹红Ⅰ、Ⅱ的检测。其检出限分别为0.024μg/g0、.027μg/g。

  4. The deconjugation ability of bacteria isolated from the jejunal fluids in the blind loop syndrome with high 14CO2 excretion--using the breath analysis technique and thin-layer chromatography.

    Science.gov (United States)

    Shindo, K; Yamazaki, R; Mizuno, T; Shionoiri, H; Sugiyama, M

    1989-01-01

    Five patients with blind loop syndrome (Billroth II) were examined by measuring 14CO2 specific activity of expired breath samples taken at intervals after a meal containing glycine-1-14C cholate. The 5 patients tested showed a marked increase of 14CO2 specific activity. Furthermore, the ability of deconjugation of bacteria isolated from the jejunal fluids in the efferent loop of these patients was tested by thin layer chromatography. The bacterial species identified from the samples were as follows: enterococcus, Lactobacillus (L) buchneri, L. bifidus, L. brevis, Eubacterium (E) lentum, Bacteroides (B) vulgaricus, B. filamentosum, Corynebacterium (C) granulosum, Escherichia (E) coli, Staphylococcus (S) epidermidis, and Aerobacter (A) aerogenes. These species of bacteria, except E. coli and A. aerogenes, showed the deconjugation ability by which conjugated bile acids in ox gall was hydrolyzed. Administration of chloramphenicol (1g per day for 14 days orally divided doses) to the 5 patients reduced 14CO2 specific activity significantly. On the other hand, 9 healthy men (control subjects) who were tested showed a flat curve, and 8 of the 9 had no growth of bacteria isolated from the jejunal fluids. The remaining healthy man showed an overgrowth of E. coli and Pseudomonas (P) aeruginosa, but the species did not have the ability of deconjugation. Thus, we concluded that the patients with blind loop syndrome(Billroth II) had the bacterial overgrowth in the efferent loop that contained species with deconjugation ability, and, as a result the bacterial overgrowth contributed to causing abnormalities (increased deconjugation) in the metabolism of bile acids in the small intestine. When the concentration of conjugated bile acids in the small intestine was reduced to levels below the critical micellar concentration by several factors, fat malabsorption and subsequent steatorrhea were induced (1,-4). Furthermore, H. Fromm and A. F. Hofmann presented in vivo that the patients

  5. Thin Layer Drying Kinetics of of Roselle

    Directory of Open Access Journals (Sweden)

    Suherman

    2012-02-01

    Full Text Available This study was performed to determine the most appropriate thin layer drying model and the effective moisture diffusivity of Roselle (Hibiscus sabdariffa. Roselle with an Initial Moisture Content (IMC of 85%, on wet basis (wb was dried in a conventional tray dryer at temperatures of 40, 50 and 60ºC. The drying data were fitted to eleven thin layer models and a thin layer model for the roselle calyx was developed by regressing the coefficients of the best fit model. The newton model was most adequate model for describing the thin layer drying kinetics of the roselle calyx. The drying constant was found to vary linearly with temperature. Also, effective diffusivity was evaluated by using Fick’s second law, which varied from 1.405 x 10-10 to 2.283 x 10-10 m2/s. The dependence of moisture diffusivity on temperature was described by Arrhenius type equation. The diffusivity constant D0 activation energy Ea could be, respectively, estimated as 4.5 x 10-7 m2/s and 21.02 kJ/gmol.

  6. Carbon nanofiber growth on thin rhodium layers

    NARCIS (Netherlands)

    Chinthaginjala, J.K.; Unnikrishnan, S.; Smithers, M.A.; Kip, G.A.M.; Lefferts, L.

    2012-01-01

    A thinlayer of carbon nanofibers (CNFs) was synthesized on a thin polycrystalline rhodium (Rh) metal layer by decomposing ethylene in the presence of hydrogen. Interaction of Rh crystals with carbon results in fragmentation and formation of Rh-nanoparticles, facilitating CNF growth. CNFs are immobil

  7. Subsurface Raman analysis of thin painted layers.

    Science.gov (United States)

    Conti, Claudia; Colombo, Chiara; Realini, Marco; Zerbi, Giuseppe; Matousek, Pavel

    2014-01-01

    Here we present, for the first time, an extension of spatially offset Raman spectroscopy to thin (tens of micrometers thick), highly turbid stratified media such as those encountered in paintings. The method permits the non-destructive interrogation of painted layers in situations where conventional Raman microscopy is not applicable due to high turbidity of the top layer(s). The concept is demonstrated by recovering the pure Raman spectra of paint sub-layers that are completely obscured by paint over-layers. Potential application areas include the analysis of paintings in art preservation and restoration avoiding the cross-sectional analysis used currently with this type of samples. The technique also holds promise for the development as a non-destructive subsurface tool for in situ analysis using portable instruments.

  8. 萃取浓缩-薄涂柱气相色谱法测定煤焦油废水中的联苯和菲%Determination of Biphenyl and Phenanthrene in Coal Tar Wastewater by Gas Chromatography with Thin Layer Column after Extraction Concentration

    Institute of Scientific and Technical Information of China (English)

    吴俐

    2001-01-01

    The biphenyl and phenanthrene in coal tar wastewater are firstconcentrated by extraction with benzene and then determined by gas chromatography with thin layer column.The results show that the method is characterized by lower column temperature,quick determination and higher accuracy.%用苯萃取浓缩煤焦油废水中的联苯和菲,然后用薄涂柱气相色谱法进行测定。试验表明:该法具有色谱柱温低、快速、准确等特点。

  9. Determinação de aflatoxina B1 em pimenta (Piper nigrum L. e orégano (Origanum vulgare L. por cromatografia em camada delgada e densitometria Determination of aflatoxin B1 (Piper nigrum L. and oregano (Origanum vulgare L. by thin-layer chromatography and densitometry

    Directory of Open Access Journals (Sweden)

    Guilherme Prado

    2008-01-01

    Full Text Available An analytical study based on extraction with methanol-water, immunoaffinity cleanup and separation, identification and quantification of aflatoxin B1 by thin-layer chromatography,in ground black and white pepper and oregano was carried out. Validation of the applied methodology was done through accuracy and precision studies. Recoveries of aflatoxin B1 and relative standard deviations, from spice samples spiked at levels from 4.86 to 97.70 µg/kg, were, respectively, higher than 72% and lower than 20%. Application to spice samples available in Minas Gerais state, purchased at popular markets, showed no contamination with aflatoxin B1.

  10. An Electrochemical Experiment Using an Optically Transparent Thin Layer Electrode

    Science.gov (United States)

    DeAngelis, Thomas P.; Heineman, William R.

    1976-01-01

    Describes a unified experiment in which an optically transparent thin layer electrode is used to illustrate the techniques of thin layer electrochemistry, cyclic voltammetry, controlled potential coulometry, and spectroelectrochemistry. (MLH)

  11. Thin layer and nuclear magnetic resonance magnetometers

    International Nuclear Information System (INIS)

    In the first part of this text, magnetometers with sensitive elements in the form of thin cylindrical ferromagnetic layers are described. These layers are anisotropic, uniaxial, C orientated and single domains. In the second part of the text, the principles of the nuclear magnetic resonance magnetometer realized at the LETI are presented. This instrument is accurate, of high efficiency, and isotropic. Very small variations in magnetic field intensity (10-7 oersteds) can be detected with a 1Hz pass band at zero frequency

  12. Method of transferring a thin crystalline semiconductor layer

    Science.gov (United States)

    Nastasi, Michael A.; Shao, Lin; Theodore, N. David

    2006-12-26

    A method for transferring a thin semiconductor layer from one substrate to another substrate involves depositing a thin epitaxial monocrystalline semiconductor layer on a substrate having surface contaminants. An interface that includes the contaminants is formed in between the deposited layer and the substrate. Hydrogen atoms are introduced into the structure and allowed to diffuse to the interface. Afterward, the thin semiconductor layer is bonded to a second substrate and the thin layer is separated away at the interface, which results in transferring the thin epitaxial semiconductor layer from one substrate to the other substrate.

  13. 茶叶中儿茶素薄层色谱分离所用展开剂的优化%Optimization of developing solvents of high performance thin-layer chromatography for separating catechins in tea

    Institute of Scientific and Technical Information of China (English)

    王丽丽; 王坤波; 黄建安; 徐仲溪

    2012-01-01

    室温条件下,以硅胶板为固定相,用5种展开剂(体积比9:9:2的甲苯-丙酮-甲酸、5.0:10.0:1.0:0.5的甲苯-甲酸乙酯-甲醇-甲酸、8.0:5.0:15.0:0.3的甲苯-三氯钾烷-丙酮-甲酸、12.5:7.5:1.8:0.6的三氯钾烷-丙酮-甲醇-水、12.5:7.5:1.8:0.6的三氯钾烷-丙酮-甲酸-水)对茶叶中的儿茶素进行薄层色谱分离,筛选出其中较优的展开剂后,进一步优化其配比,并用其分离绿茶和白茶提取物中的儿茶素以进行验证.结果表明,以体积比12.5:7.5:2.2的三氯甲烷-丙酮-甲酸为展开剂,茶叶内主要的4种儿茶素单体(EGCg、EGC、ECg、EC)可得到良好分离,绿茶与白茶提取物中的儿茶素能较好地得以分离.%At room temperature, methylbenzene-acetone-formic acid (9∶9 ∶ 2, V/V), methylbenzene-ethyl formatemethanol-formic acid (5.0 ∶10.0∶ 1.0 ∶0.5, V/V), methylbenzene-chloroform-acetone-formic acid (8.0 ∶5.0∶ 15.0∶ 0.3, V/V), chloroform-acetone-methanol-water(12.5 ∶7.5 ∶1.8 ∶ 0.6, V/V) and chloroform-acetone-formic acid-water (12.5 ∶ 7.5 ∶ 1.8 ∶ 0.6, V/V) on silica gel marked as solvent Ⅰ,Ⅱ,Ⅲ,Ⅳ and Ⅴ respectively were applied as developing solvent respectively in high performance thin-layer chromatography (HPTLC) for isolating catechins in the tea. Among them, solvent Ⅴ was found to be the best for separation of catechins, this solvent was then modified mainly regarding the volume ratios of formic acid. The results showed the modified solvent Ⅴ, namely, chloroform- acetone- formic acid (12.5 ∶ 7.5 ∶2.2, V/V) was the optimum for separation of the four main catechins (EGCg, EGC, Ecg, EC) in the tea. The applicability of the optimized developing solvent was further confirmed by separation of catechins in the extracts of the green and the white tea.

  14. SDS-PAGE-薄层扫描联用法测定3种不同来源的乳铁蛋白%Determination of Lactoferrin from Different Sources by SDS-PAGE Followed by Thin Layer Chromatography Scanning

    Institute of Scientific and Technical Information of China (English)

    邢志恩; 王军; 戴蕴青; 陈燕卉; 陈敏

    2011-01-01

    目的:建立快速、简便测定鲜牛奶、转基因牛奶和人乳中乳铁蛋白的方法。方法:在对样品脱脂和去除酪蛋白时,水洗乳脂、酪蛋白以提高乳铁蛋白的回收率。通过十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(sodiumdodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)分离乳清蛋白,薄层扫描法定量。对电泳和薄层扫描的条件进行优化,电泳使用1.0mm×10齿的试样格、分离胶质量浓度12g/mL、分离电压100V、上样量5μL、染色3h、脱色2h;薄层扫描采取锯齿、双波长、透射的扫描方式,Y步长和摆幅宽分别为0.1mm和8mm。结果:可以分离不同来源乳中的乳铁蛋白、α-乳白蛋白和β-乳球蛋白;乳铁蛋白加标回收率分别为104.53%、108.37%,同板精密度RSD值为3.1003%和1.8151%,在100~2000μg/mL范围内呈线性关系,相关系数为0.9988和0.9990。结论:此方法可以用于3种乳中乳铁蛋白的测定。%The aim of this study was to develop a rapid and simple method for the determination of lactoferrin from fresh bovine milk,transgenic bovine milk and human milk.After removing fat by centrifugation and precipitating caseins by adjusting pH,the lactoferrin contents were separated by SDS-PAGE(100 V,12 g/mL gel,comb:1.0 × 10 teeth,5μL injection,staining for 3 h and destaining for 2 h);and then the target fractions in the gel were examined by thin layer chromatography scanner(transmission,zigzag scan,dual wavelength,swing width: 8 mm,delta Y: 0.1 mm).The results showed that good separation was achieved for lactoferrin(LF),α-lactalbumin(α-La) and β-lactoglobulin(β-Lg) from three different sources.The recoveries for LFI(LF standard obtained from fresh bovine milk) in fresh bovine milk and LFII(LF standard obtained from transgenic bovine milk) in transgenic bovine milk across three spike levels were 104.53% and 108.37%,respectively.The intra-plate assay precision RSDs for

  15. Magnetotransport Measurements of Thin Layered WTe2

    Science.gov (United States)

    Sun, Bosong; Fei, Zaiyao; Wu, Sanfeng; Finney, Joe; Nguyen, Paul; Yan, Jiaqiang; Palomaki, Tauno; Xu, Xiaodong; Cobden, David

    Tungsten Telluride, a semimetallic layered transition-metal dichalcogenide, was recently found to have extremely large magnetoresistance at helium temperatures. The unconventional non-saturating behavior may be related to near-perfect charge compensation between electron and hole pockets, but this is still debated. Since that discovery there have been several studies of angle-resolved photoemission and quantum transport on the bulk material which found the fermi surface to be rather complex. It is clear that insights stand to be gained from the variation of the properties on thinning down to a single monolayer. Measurements of thin exfoliated crystals have indicated that the carriers become increasingly localized on approaching the monolayer limit. This may be an intrinsic feature or it may be a result of the disorder produced by oxidation of the surface layers. We report transport measurements on few-layer and monolayer WTe2 with and without encapsulation in hBN, including the dependence on thickness, crystal axis, temperature, gate voltage and magnetoresistance, which resolve this question.

  16. RF screening by thin resistive layers

    CERN Document Server

    Caspers, Friedhelm; González, C; Jensen, E; Keil, Eberhard; Morvillo, M; Ruggiero, F; Schröder, G; Zotter, Bruno W; Dyachkov, M

    1999-01-01

    We discuss the results of recent impedance measurements for an LHC dump kicker prototype, performed at CERN using the coaxial wire method. The kicker design includes a vacuum barrier consisting of a ceramic chamber internally coated with a thin metallic layer having good electric contact with the external beam pipe. For the bench test the coated ceramic tube was replaced by a kapton foil with a 0.2 \\mu\\m copper layer having the same DC resistance of 0.7 Ømega\\m. The measurements show that this resistive coating provides a very effective RF screening down to frequencies below 1 MHz, where the skin depth is two orders of magnitude larger than the layer thickness and one could expect full penetration of the electromagnetic fields. We also present simulation results and analytic considerations in agreement with the measurements, showing that the return currents almost entirely flow through the copper layer down to frequencies where the reactive impedance of the kicker elements located behind it becomes comparabl...

  17. Development and validation of a simple high performance thin layer chromatography method combined with direct 1,1-diphenyl-2-picrylhydrazyl assay to quantify free radical scavenging activity in wine.

    Science.gov (United States)

    Agatonovic-Kustrin, Snezana; Morton, David W; Yusof, Ahmad P

    2016-04-15

    The aim of this study was to: (a) develop a simple, high performance thin layer chromatographic (HPTLC) method combined with direct 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay to rapidly assess and compare free radical scavenging activity or anti-oxidant activity for major classes of polyphenolics present in wines; and (b) to investigate relationship between free radical scavenging activity to the total polyphenolic content (TPC) and total antioxidant capacity (TAC) in the wine samples. The most potent free radical scavengers that we tested for in the wine samples were found to be resveratrol (polyphenolic non-flavonoid) and rutin (flavonoid), while polyphenolic acids (caffeic acid and gallic acid) although present in all wine samples were found to be less potent free radical scavengers. Therefore, the total antioxidant capacity was mostly affected by the presence of resveratrol and rutin, while total polyphenolic content was mostly influenced by the presence of the less potent free radical scavengers gallic and caffeic acids.

  18. Thin layer convection-drying of mushrooms

    Energy Technology Data Exchange (ETDEWEB)

    Pal, U.S.; Chakraverty, A. [Indian Inst. of Tech., Kharagpur (India). Dept. of Agricultural Engineering

    1997-06-01

    Dehydration characteristics of the Oyster Pleurotus variety of mushroom were studied. Both untreated and treated (steam blanching followed by sulphiting and citric acid pretreatment before drying) mushrooms were dried in the thin layer experimental equipment at each of the drying air temperatures of 45, 50 and 60{sup o}C with air velocities of 0.9 and 1.6 m/s. Studies on the equilibrium moisture content (EMC) of both untreated and treated dehydrated mushrooms were performed at different relative humidities ranging from 11.2 to 86.3% at 30{sup o}C. Taking drying time and quality of the dehydrated product into account, a combination of a drying air temperature of 50{sup o}C and an air velocity of 0.9 m/s appears to be suitable for drying of both untreated and treated mushrooms for a good dehydrated product. (author)

  19. Plant thin cell layers: update and perspectives

    Directory of Open Access Journals (Sweden)

    Teixeira da Silva Jaime A.

    2015-12-01

    Full Text Available Thin cell layers (TCLs are small and versatile explants for the in vitro culture of plants. At face value, their morphogenic productivity may appear to be less than conventional explants, but once the plant growth correction factor and geometric factor have been applied, the true (potential productivity exceeds that of a conventional explant. It is for this reason that for almost 45 years, TCLs have been applied to the in vitro culture of almost 90 species or hybrids, mainly ornamentals and orchids, but also to field and vegetable crops and medicinal plants. Focusing on 12 new studies that have emerged in the recent past (2013-2015, this paper brings promise to other horticultural species that could benefit from the use of TCLs.

  20. A simple and rapid method for the determination of taxol produced by fungal endophytes from medicinal plants using high performance thin layer chromatography%高效薄层色谱法快速测定由药用植物内生真菌产生的紫杉醇

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Taxol is an important anticancer drug used widely in the clinical field. In this study, some endophytic fungi were isolated from selected medicinal plants, and were screened for their potential in the production of taxol, using a rapid separation technique of high performance thin layer chromatography ( HPTLC ). Of the 20 screened fungi, only 13 fungal species produced taxol in the artificial culture medium.The results of HPTLC showed that the 13 fungal species had identical ultraviolet (UV) characteristics, positive reactivity with a spray reagent, yielding a blue spot, which turned to dark gray after 24 hours, and had Rf values identical to that of the authentic taxol. The amount of taxol was also quantified by comparing the peak area and the peak height of the fungal samples with those of authentic taxol.

  1. 薄层层析-分光光度法检测纤毛虫中的卵磷脂%Determination of Phosphatidylcholine in Protozoa by Thin Layer Chromatography-Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    盛东峰; 孙明俊

    2012-01-01

    卵磷脂(PC)在纤毛虫中含量比较稳定,通过纤毛虫PC含量来估计出纤毛虫的量.采用薄层层析-分光光度法测定了山羊瘤胃纤毛虫中PC的含量,结果表明山羊瘤胃纤毛虫PC含量为17.9~24.1 mg/g.该法简便、快速、有效,可作为纤毛虫卵磷脂含量的检测方法.%Phosphatidylcholine (PC) is a special stable marker in the protozoa, the content of which could be used as an indicator for evaluating the quantity of protozoa. Thin layer chrornatography-spectroscopy was established to determine the content of PC in the protozoa. The results showed that the content of phosphatidylcholine in protozoa was in the range of 17.8~ 24.2 mg/g. In conclusion, this method was simple, rapid and efficient. It can be used for determining the relative content of phosphatidylcholine in protozoa.

  2. Thin-Layer Fuel Cell for Teaching and Classroom Demonstrations

    Science.gov (United States)

    Shirkhanzadeh, M.

    2009-01-01

    A thin-layer fuel cell is described that is simple and easy to set up and is particularly useful for teaching and classroom demonstrations. The cell is both an electrolyzer and a fuel cell and operates using a thin layer of electrolyte with a thickness of approximately 127 micrometers and a volume of approximately 40 microliters. As an…

  3. Thin-Layer Spectroelectrochemistry on an Aqueous Micro-drop

    Energy Technology Data Exchange (ETDEWEB)

    Schroll, Cynthia A.; Chatterjee, Sayandev; Heineman, William R.; Bryan, Samuel A.

    2012-05-01

    Here we report the ability to perform thin-layer spectroelectrochemistry using an aqueous micro-drop. The thin-layer setup was evaluated using [Fe(CN){sub 6}]{sup 3-/4-} as a absorbance based model analyte and [Ru(bpy){sub 3}]{sup 3+/2+} as an emission based model analyte. The thin-layer capability of the electrochemical cell was validated with these two chemical systems using cyclic voltammetry, and UV-visible absorbance and luminescence spectroscopies. This work supports our FCRD process monitoring work and is a direct result of the collaboration under subcontract with University of Cincinnati.

  4. Buffer layer for thin film structures

    Energy Technology Data Exchange (ETDEWEB)

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2006-10-31

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  5. Buffer layer for thin film structures

    Science.gov (United States)

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2010-06-15

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  6. Delamination of Compressed thin Layers at Corners

    DEFF Research Database (Denmark)

    Clausen, Johan; Jensen, Henrik Myhre; Sørensen, Kim Dalsten

    2008-01-01

    An analysis of delamination for a thin elastic film, attached to a substrate with a corner, is carried out. The film is in compression and the analysis is performed by combining results from fracture mechanics and the theory of thin shells. The results show a very strong dependency of the angle...

  7. Comparison on the Contents of Cholic Acid in Natural Calculus Bovis and Calculus Bovis Artifactus Determined by Thin Layer Chromatography Scanning%薄层扫描法测定天然牛黄与人工牛黄胆酸含量比较

    Institute of Scientific and Technical Information of China (English)

    王志强; 刘海津

    2011-01-01

    Objective:To determine and compare the total contents of cholic acid in natural calculus bovis and calculus bovis artifactus in 6 product units. Methods: The silica G thin layer plate was used with isooctane - butyl acetate - glacial acetic acid - formic acid (8 : 4 : 2 : 1) as developing solvent, λs =380 nm,λR =650 nm,in the reflection of jagged scanning. Results:The content of cholic acid in calculus bovis artifactus was the same as that in natural calculus bovis. The content of free bile acid in calculus bovis artifactus was more than that in natural calculus bovis. Therefore, calculus bovis artifactus could be the substitute for natural calculus bovis within limits. Conclusion: Thin layer chromatography ( TLC ) scanning is a reliable method to determine the contents of cholic acid in natural calculus bovis and calculus bovis artifactus.%摘要:目的:测定天然牛黄与6个生产单位的人工牛黄中胆酸的含量总量比较。方法:硅胶G薄层板,异辛烷—醋酸丁酯—冰醋酸—甲酸(8∶4∶2∶1)为展开剂,λS= 380ntm,λR=650ntm,用反射法锯齿形扫描。结果:人工牛黄与天然牛黄中的胆酸成分相同,且人工牛黄中的游离胆汁酸比天然牛黄略高,在一定范围内,人工牛黄可替代天然牛黄。结论:薄层扫描法测定天然牛黄与人工牛黄中胆酸含量方法可靠。

  8. Diamond nucleation on surface of C60 thin layers

    Institute of Scientific and Technical Information of China (English)

    杨国伟; 袁放成; 刘大军; 何金田; 张兵临

    1997-01-01

    Diamond nucleation on the surface of C60 thin layers and intermediate layer of Si substrates are studied by scanning electron microscopy (SEM). The cross-section SEM images of diamond films show that diamond grains really nucleate on the surface of C60 thin layers. The SEM images of diamond nucleating sites show the nucleating aggregation of diamond on C60 surfaces. The preferential oriented diamond films are observed. The plasma pre-treatment of C60 sublimating layers is a key factor for diamond nucleation.

  9. Layer-by-Layer Assembly of a pH-Responsive and Electrochromic Thin Film

    Science.gov (United States)

    Schmidt, Daniel J.; Pridgen, Eric M.; Hammond, Paula T.; Love, J. Christopher

    2010-01-01

    This article summarizes an experiment on thin-film fabrication with layer-by-layer assembly that is appropriate for undergraduate laboratory courses. The purpose of this experiment is to teach students about self-assembly in the context of thin films and to expose students to the concepts of functional polymeric coatings. Students dip coat…

  10. Thin layer structure of dissipation rate of scalar turbulence

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Haibing; (周海兵); CUI; Guixiang; (崔桂香); XU; Chunxiao; (许春晓); ZHANG; Zhaoshun; (张兆顺)

    2003-01-01

    The structure of scalar turbulence dissipation is studied by means of direct numerical simulation. It has been discovered that the scalar turbulence dissipation exhibits thin layer structure. Based on the analysis of transportation equation of scalar turbulence dissipation, we have investigated the effect of turbulent strains on the generation of scalar turbulence dissipation and found that fluctuating scalar gradients trend to the third principal direction of turbulent strains. Therefore the generation of the thin layer structure of scalar turbulence dissipation is well interpreted.

  11. Determination of 131I-hippuran and its main contaminants by thin-layer cromatography

    International Nuclear Information System (INIS)

    Thin-layer elution-spectrophotometric and densitometric methods were developed for the simultaneous determination of orthoidohippuric acid and its main contaminant, orthoiodobenzoic acid after their chromatographic separation using a methanol-chloroform-acetic acid 100:75:2.5 solvent mixture and Kieselgel 60 F254 layer. Benzyl alcohol, also present in the pharmaceutical preparation, does not interfere. The precision of the procedures corresponds to that of radio paper chromatography. It is pointed out that, besides the orthoiodobenzoic acid, traces of other similar 131I-labelled organic contaminants may be present in the preparation. (author)

  12. 鸡血藤与其常见混淆品的薄层色谱鉴别研究%Identification of Caulis Spatholobi and Its Common Adulterants with Thin Layer Chromatography

    Institute of Scientific and Technical Information of China (English)

    翟明; 刘军民

    2012-01-01

    Objective To investigate thin layer chromalography (TLC) conditions for the identification of Caulis Spatholobi and its common adulterants, and to study the differences in chemical composition of different populations of wild germplasm through TLC fingerprint analysis. Methods With the mixture of chloroform-methanol-formic acid (volume ratio being 7 : 1 :0. 2) and chloroform-acetone-formic acid (volume ratio being 8 : 1 : 0. 5) as developing agents, and with 5% (volume fraction) sulfuric acid-ethanol solution as the color developing reagent, TLC was used for the identification of Caulis Spatholobi and its common adulterants . The composition of different populations of Caulis Spatholobi was well separated with the mixture of chloroform-methanol-formic acid ( volume ratio being 10 :1:0.4). Finally, we used unweighted pair-group method of Ntsys 2. 10 software and arithmetic means ( UPGMA) for cluster analysis of the quality differences in various populations of Caulis Spatholobi. Results We have established TLC method for the identification of Caulis Spatholobi and its common adulterants, and established Caulis Spatholobi TLC fingerprints which consisted of 13 specific fluorescent spots. Through cluster analysis, 11 populations of genuine Caulis Spatholohi were grouped inlo four categories. Conclusion TLC can be used to effectively identify the medicinal material of Caulis Spalholobi. Great variability exists in different populations of wild germplasm of Caulis Spatholobi.%[目的]探讨鸡血藤与其常见混淆品的薄层色谱鉴别条件,并开展鸡血藤薄层色谱指纹图谱的初步研究,分析不同居群鸡血藤野生种质在化学组分上的差异.[方法]采用三氯甲烷—甲醇—甲酸(体积比为7∶1∶0.2)和三氯甲烷—丙酮—甲酸(体积比为8∶1∶0.5)为展开剂,体积分数5%硫酸乙醇溶液显色,可鉴别鸡血藤与其常见混淆品;三氯甲烷—甲醇—甲酸(体积比为10∶1∶0.4)能很好地分离不同

  13. Buffer layers for high-Tc thin films on sapphire

    Science.gov (United States)

    Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

    1992-01-01

    Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

  14. Thin-film organic photonics molecular layer deposition and applications

    CERN Document Server

    Yoshimura, Tetsuzo

    2011-01-01

    Among the many atomic/molecular assembling techniques used to develop artificial materials, molecular layer deposition (MLD) continues to receive special attention as the next-generation growth technique for organic thin-film materials used in photonics and electronics. Thin-Film Organic Photonics: Molecular Layer Deposition and Applications describes how photonic/electronic properties of thin films can be improved through MLD, which enables precise control of atomic and molecular arrangements to construct a wire network that achieves ""three-dimensional growth"". MLD facilitates dot-by-dot--o

  15. thin films grown with additional NaF layers

    Science.gov (United States)

    Kim, Gee Yeong; Kim, Juran; Jo, William; Son, Dae-Ho; Kim, Dae-Hwan; Kang, Jin-Kyu

    2014-10-01

    CZTS precursors [SLG/Mo (300 nm)/ZnS (460 nm)/SnS (480 nm)/Cu (240 nm)] were deposited by RF/DC sputtering, and then NaF layers (0, 15, and 30 nm) were grown by electron beam evaporation. The precursors were annealed in a furnace with Se metals at 590°C for 20 minutes. The final composition of the CZTSSe thin-films was of Cu/(Zn + Sn) ~ 0.88 and Zn/Sn ~ 1.05, with a metal S/Se ratio estimated at ~0.05. The CZTSSe thin-films have different NaF layer thicknesses in the range from 0 to 30 nm, achieving a ~3% conversion efficiency, and the CZTSSe thin-films contain ~3% of Na. Kelvin probe force microscopy was used to identify the local potential difference that varied according to the thickness of the NaF layer on the CZTSSe thin-films. The potential values at the grain boundaries were observed to increase as the NaF thickness increased. Moreover, the ratio of the positively charged GBs in the CZTSSe thin-films with an NaF layer was higher than that of pure CZTSSe thin-films. A positively charged potential was observed around the grain boundaries of the CZTSSe thin-films, which is a beneficial characteristic that can improve the performance of a device.

  16. Thin bacteria/Layered Double Hydroxide films using a layer-by-layer approach.

    Science.gov (United States)

    Halma, Matilte; Khenifi, Aicha; Sancelme, Martine; Besse-Hoggan, Pascale; Bussière, Pierre-Olivier; Prévot, Vanessa; Mousty, Christine

    2016-07-15

    This paper reports the design of thin bacteria/Layered Double Hydroxides (LDH) films in which bacterial cells of Pseudomonas sp. strain ADP were assembled alternatively with Mg2Al-NO3 LDH nanosheets by a layer-by-layer deposition method. The UV-Vis spectroscopy was used to monitor the assembly process, showing a progressive increase in immobilized bacteria amount upon deposited cycles. The {ADP/LDH}n film was characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy and atomic force microscopy. The metabolic activity of immobilized bacteria was determined using chronoamperometry by measuring the biochemical oxygen demand in presence of glucose using an artificial electron acceptor (Fe(CN)6(3-)) at 0.5V/Ag-AgCl. A steady current of 0.250μAcm(-2) was reached in about 30s after the addition of 5mM glucose. PMID:27124809

  17. In situ imaging and control of layer-by-layer femtosecond laser thinning of graphene

    Science.gov (United States)

    Li, D. W.; Zhou, Y. S.; Huang, X.; Jiang, L.; Silvain, J.-F.; Lu, Y. F.

    2015-02-01

    Although existing methods (chemical vapor deposition, mechanical exfoliation, etc.) are available to produce graphene, the lack of thickness control limits further graphene applications. In this study, we demonstrate an approach to precisely thin graphene films to a specific thickness using femtosecond (fs) laser raster scanning. By using appropriate laser fluence and scanning times, graphene thinning with an atomic layer precision, namely layer-by-layer graphene removal, has been realized. The fs laser used was configured in a four-wave mixing (FWM) system which can be used to distinguish graphene layer thickness and count the number of layers using the linear relationship between the FWM signal intensity and the graphene thickness. Furthermore, FWM imaging has been successfully applied to achieve in situ, real-time monitoring of the fs laser graphene thinning process. This method can not only realize the large-scale thinning of graphene with atomic layer precision, but also provide in situ, rapid imaging capability of graphene for an accurate assessment of the number of layers.Although existing methods (chemical vapor deposition, mechanical exfoliation, etc.) are available to produce graphene, the lack of thickness control limits further graphene applications. In this study, we demonstrate an approach to precisely thin graphene films to a specific thickness using femtosecond (fs) laser raster scanning. By using appropriate laser fluence and scanning times, graphene thinning with an atomic layer precision, namely layer-by-layer graphene removal, has been realized. The fs laser used was configured in a four-wave mixing (FWM) system which can be used to distinguish graphene layer thickness and count the number of layers using the linear relationship between the FWM signal intensity and the graphene thickness. Furthermore, FWM imaging has been successfully applied to achieve in situ, real-time monitoring of the fs laser graphene thinning process. This method can not

  18. Chromatographic separation of inorganic ions on thin layers of titanium phosphate ion-exchanger.

    Science.gov (United States)

    Ghoulipour, Vanik; Safari, Moharram

    2014-12-01

    The chromatographic behavior of 30 inorganic cations has been studied on thin layers of titanium phosphate ion-exchanger using several aqueous, organic and mixed mobile phases. The separation of one ion from several other ions and also ternary and binary separations have been developed. Some important analytical separations are reported. The effect of pH of the mobile phase on retention factor (Rf) values of the cations in the presence of complex-forming anion along with the separation power of the ion-exchanger were studied. This ion-exchanger exhibits high sorption capacity and varying selectivity towards metal ions and makes it a suitable stationaiy phase in thin layer chromatography.

  19. Chromatographic separation of inorganic ions on thin layers of titanium phosphate ion-exchanger

    Institute of Scientific and Technical Information of China (English)

    Vanik GHOULIPOUR; Moharram SAFARI

    2014-01-01

    The chromatographic behavior of 30 inorganic cations has been studied on thin layers of titanium phosphate ion-exchanger using several aqueous,organic and mixed mobile phases. The separation of one ion from several other ions and also ternary and binary separations have been developed. Some important analytical separations are reported. The effect of pH of the mobile phase on retention factor(Rf)values of the cations in the presence of complex-forming anion along with the separation power of the ion-exchanger were studied. This ion-exchanger exhibits high sorption capacity and varying selectivity towards metal ions and makes it a suitable stationary phase in thin layer chromatography.

  20. High-performance thin-layer chromatography linked with (bio)assays and mass spectrometry - a suited method for discovery and quantification of bioactive components? Exemplarily shown for turmeric and milk thistle extracts.

    Science.gov (United States)

    Taha, Mahmoud N; Krawinkel, Michael B; Morlock, Gertrud E

    2015-05-15

    Extraction parameters, chemical fingerprint, and the single compounds' activity levels were considered for the selection of active botanicals. For an initial survey, the total bioactivity (i.e., total reducing capacity, total flavonoids contents and free radical scavenging capacity) of 21 aqueous and 21 ethanolic plant extracts was investigated. Ethanolic extracts showed a higher yield and were further analyzed by HPTLC in detail to obtain fingerprints of single flavonoids and further bioactive components. Exemplarily shown for turmeric (Curcuma longa) and milk thistle (Silybum marianum), effect-directed analysis (EDA) was performed using three selected (bio)assays, the Aliivibrio fischeri bioassay, the Bacillus subtilis bioassay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH*) assay. As a proof of principle, the bioactive components found in the extracts were confirmed by HPTLC-MS. Bioassays in combination with planar chromatography directly linked to the known, single effective compounds like curcumin and silibinin. However, also some unknown bioactive components were discovered and exemplarily characterized, which demonstrated the strength of this kind of EDA. HPTLC-UV/Vis/FLD-EDA-MS could become a useful tool for selection of active botanicals and for the activity profiling of the active ingredients therein. The flexibility in effect-directed detections allows a comprehensive survey of effective ingredients in samples. This streamlined methodology comprised a non-targeted, effect-directed screening first, followed by a highly targeted characterization of the discovered bioactive compounds. HPTLC-EDA-MS can also be recommended for bioactivity profiling of food on the food intake side, as not only effective phytochemicals, but also unknown bioactive degradation products during food processing or contamination products or residues or metabolites can be detected. Thus, an efficient survey on potential food intake effects on wellness could be obtained. Having performed

  1. High-performance thin-layer chromatography linked with (bio)assays and mass spectrometry - a suited method for discovery and quantification of bioactive components? Exemplarily shown for turmeric and milk thistle extracts.

    Science.gov (United States)

    Taha, Mahmoud N; Krawinkel, Michael B; Morlock, Gertrud E

    2015-05-15

    Extraction parameters, chemical fingerprint, and the single compounds' activity levels were considered for the selection of active botanicals. For an initial survey, the total bioactivity (i.e., total reducing capacity, total flavonoids contents and free radical scavenging capacity) of 21 aqueous and 21 ethanolic plant extracts was investigated. Ethanolic extracts showed a higher yield and were further analyzed by HPTLC in detail to obtain fingerprints of single flavonoids and further bioactive components. Exemplarily shown for turmeric (Curcuma longa) and milk thistle (Silybum marianum), effect-directed analysis (EDA) was performed using three selected (bio)assays, the Aliivibrio fischeri bioassay, the Bacillus subtilis bioassay and the 2,2-diphenyl-1-picrylhydrazyl (DPPH*) assay. As a proof of principle, the bioactive components found in the extracts were confirmed by HPTLC-MS. Bioassays in combination with planar chromatography directly linked to the known, single effective compounds like curcumin and silibinin. However, also some unknown bioactive components were discovered and exemplarily characterized, which demonstrated the strength of this kind of EDA. HPTLC-UV/Vis/FLD-EDA-MS could become a useful tool for selection of active botanicals and for the activity profiling of the active ingredients therein. The flexibility in effect-directed detections allows a comprehensive survey of effective ingredients in samples. This streamlined methodology comprised a non-targeted, effect-directed screening first, followed by a highly targeted characterization of the discovered bioactive compounds. HPTLC-EDA-MS can also be recommended for bioactivity profiling of food on the food intake side, as not only effective phytochemicals, but also unknown bioactive degradation products during food processing or contamination products or residues or metabolites can be detected. Thus, an efficient survey on potential food intake effects on wellness could be obtained. Having performed

  2. Ultra-thin Metal and Dielectric Layers for Nanophotonic Applications

    DEFF Research Database (Denmark)

    Shkondin, Evgeniy; Leandro, Lorenzo; Malureanu, Radu;

    2015-01-01

    In our talk we first give an overview of the various thin films used in the field of nanophotonics. Then we describe our own activity in fabrication and characterization of ultra-thin films of high quality. We particularly focus on uniform gold layers having thicknesses down to 6 nm fabricated by......-beam deposition on dielectric substrates and Al-oxides/Ti-oxides multilayers prepared by atomic layer deposition in high aspect ratio trenches. In the latter case we show more than 1:20 aspect ratio structures can be achieved....

  3. Channel cracks in atomic-layer and molecular-layer deposited multilayer thin film coatings

    International Nuclear Information System (INIS)

    Metal oxide thin film coatings produced by atomic layer deposition have been shown to be an effective permeation barrier. The primary failure mode of such coatings under tensile loads is the propagation of channel cracks that penetrate vertically into the coating films. Recently, multi-layer structures that combine the metal oxide material with relatively soft polymeric layers produced by molecular layer deposition have been proposed to create composite thin films with desired properties, including potentially enhanced resistance to fracture. In this paper, we study the effects of layer geometry and material properties on the critical strain for channel crack propagation in the multi-layer composite films. Using finite element simulations and a thin-film fracture mechanics formalism, we show that if the fracture energy of the polymeric layer is lower than that of the metal oxide layer, the channel crack tends to penetrate through the entire composite film, and dividing the metal oxide and polymeric materials into thinner layers leads to a smaller critical strain. However, if the fracture energy of the polymeric material is high so that cracks only run through the metal oxide layers, more layers can result in a larger critical strain. For intermediate fracture energy of the polymer material, we developed a design map that identifies the optimal structure for given fracture energies and thicknesses of the metal oxide and polymeric layers. These results can facilitate the design of mechanically robust permeation barriers, an important component for the development of flexible electronics.

  4. The Application of Thin Film Ionic Self-assembled Multilayer (ISAM) Nanostructures in Electromechanical Bending Actuators and Micro-fabricated Gas Chromatography (uGC) Devices

    OpenAIRE

    Wang, Dong

    2015-01-01

    Ionic self-assembled multilayer (ISAM) thin film nanostructures, including highly porous and conductive gold nanoparticles (GNP), and highly porous and thermally stable silica nanoparticles (SNP), were fabricated via the layer-by-layer (LbL) self-assembly technique. Their application in ionic polymer-metal composite (IPMC) electromechanical bending actuators and microfabricated gas chromatography (microGC) devices were investigated and significant performance improvements of these devices wer...

  5. ANTIREFLECTION MULTILAYER COATINGS WITH THIN METAL LAYERS

    Directory of Open Access Journals (Sweden)

    L. A. Gubanova

    2016-03-01

    Full Text Available The design of anti-reflective coatings for metal surfaces of Al, Ti, N,i Cr is proposed. The coatings have the form of alternating layers of dielectric/metal/dielectric with the number of cells up to15. The method of calculation of such coatings is proposed. We have calculated the coatings of the type [HfO2/Cr/HfO2]15, [ZrO2/Ti/Al2O3]15, [ZrO2/Cr/ZrO2]15. It is shown that the proposed interference coatings provide reduction of the residual reflectance of the metal several times (from 3.5 to 6.0 in a wide spectral range (300-1000 nm. The proposed coatings can be recommended as anti-reflective coatings for energy saving solar systems and batteries, and photovoltaic cells.

  6. Peculiarities of neutron waveguides with thin Gd layer

    CERN Document Server

    Khaydukov, Yu; Progliado, V; Ustinov, V; Nikitenko, Yu; Keller, T; Aksenov, V; Keimer, B

    2015-01-01

    Peculiarities of the formation of a neutron enhanced standing wave in the structure with a thin highly absorbing layer of gadolinium are considered in the article. An analogue of the poisoning effect well known in reactor physics was found. The effect is stronger for the Nb/Gd/Nb system. Despite of this effect, for a Nb/Gd bilayer and a Nb/Gd/Nb trilayer placed between Al2O3 substrate and Cu layer, it is shown theoretically and experimentally that one order of magnitude enhancement of neutron density is possible in the vicinity of the Gd layer. This enhancement makes it possible to study domain formation in the Gd layer under transition of the Nb layer(s) into the superconducting state (cryptoferromagnetic phase).

  7. Light scattering of thin azobenzene side-chain polyester layers

    DEFF Research Database (Denmark)

    Kerekes, Á.; Lörincz, E.; Ramanujam, P.S.;

    2002-01-01

    Light scattering properties of liquid crystalline and amorphous azobenzene side-chain polyester layers used for optical data storage were examined by means of transmissive scatterometry. Comparative experiments show that the amorphous polyester has significantly lower light scattering characteris...... for the domain size in thin liquid crystalline polyester layers being responsible for the dominant light scattering. The characteristic domain Sizes obtained from the Fourier transformation of polarization microscopic Pictures confirm these values.......Light scattering properties of liquid crystalline and amorphous azobenzene side-chain polyester layers used for optical data storage were examined by means of transmissive scatterometry. Comparative experiments show that the amorphous polyester has significantly lower light scattering...

  8. Effect of pirfenidone delivered using layer-by-layer thin film on excisional wound healing.

    Science.gov (United States)

    Mandapalli, Praveen Kumar; Labala, Suman; Bojja, Jagadeesh; Venuganti, Venkata Vamsi Krishna

    2016-02-15

    The aim of this study was to evaluate the effect of a new anti-fibrotic agent, pirfenidone (PFD), delivered using polyelectrolyte multilayer films on excisional wound healing. Polyelectrolyte multilayer films were prepared by layer-by-layer (LbL) sequential adsorption of chitosan and sodium alginate. The UV-spectrophotometer, FTIR and differential scanning calorimeter were used to characterize the LbL thin films. The PFD was entrapped within the LbL thin films and its effect on excisional wound healing was studied in C57BL/6. The total protein, collagen content and TGF-β expression within the wound tissue were determined after application of PFD using LbL thin films, chitosan hydrogel and polyethylene glycol hydrogel. UV-spectrophotometer and FTIR studies showed a sequential adsorption of chitosan and alginate polymer layers to form LbL thin films. The thickness of LbL thin films with 15 bilayers was found to be 15 ± 2 μm. HPLC analysis showed a PFD loading efficiency of 1.0 ± 0.1mg in 1cm(2) area of LbL thin film. In vivo wound healing studies in C57BL/6 mice showed an accelerated (thin film and commercial povidone-iodine gel (12 days). The collagen content within the wound tissue was significantly (pthin films can be utilized for excisional wound healing.

  9. Chemometrics in Fingerprinting by Means of Thin Layer Chromatography

    Directory of Open Access Journals (Sweden)

    Łukasz Komsta

    2012-01-01

    Full Text Available The paper is written as an introductory review, presenting summary of current knowledge about chemometric fingerprinting in the context of TLC, due to a rather small interest in the literature about joining TLC and chemometrics. The paper shortly covers the most important aspects of the chemometric fingerprinting in general, creating the TLC fingerprints, denoising, baseline removal, warping/registering, and chemometric processing itself. References being good candidates as a starting point are given for each topic and processing step.

  10. Robotic thin layer chromatography instrument for synthetic chemistry

    International Nuclear Information System (INIS)

    One of our long-term goals is to develop robotic workstations for automated synthetic chemistry. Toward that goal we have constructed a 2nd generation instrument for performing TLC analysis. TLC has important advantages (over HPLC and GC) in analysis of crude reaction samples and parallel sample development. The TLC instrument consist of four dedicated stations for (1) plate dispensing, (2) sample application, (3) plate development, and (4) plate densitometry. A robot is used to move plates among stations. The combination of fixed automation and robotics gives high sample throughout (up to 10 samples per hour). A second robot performs reaction chemistry and feeds samples to the TLC instrument, thus enabling TLC analysis at the same time as synthetic reactions proceed on the workstation

  11. Investigation of multi-layer thin films for energy storage.

    Energy Technology Data Exchange (ETDEWEB)

    Renk, Timothy Jerome; Monson, Todd

    2009-01-01

    We investigate here the feasibility of increasing the energy density of thin-film capacitors by construction of a multi-layer capacitor device through ablation and redeposition of the capacitor materials using a high-power pulsed ion beam. The deposition experiments were conducted on the RHEPP-1 facility at Sandia National Laboratories. The dielectric capacitor filler material was a composition of Lead-Lanthanum-Zirconium-Titanium oxide (PLZT). The energy storage can be increased by using material of intrinsically high dielectric constant, and constructing many thin layers of this material. For successful device construction, there are a number of challenging requirements including correct stoichiometric and crystallographic composition of the deposited PLZT. This report details some success in satisfying these requirements, even though the attempt at device manufacture was unsuccessful. The conclusion that 900 C temperatures are necessary to reconstitute the deposited PLZT has implications for future manufacturing capability.

  12. Thin-Layer Drying Characteristics and Modeling of Chinese Jujubes

    Directory of Open Access Journals (Sweden)

    Xiao-Kang Yi

    2012-01-01

    Full Text Available A mathematical modeling of thin-layer drying of jujubes in a convective dryer was established under controlled conditions of temperature and velocity. The drying process took place both in the accelerating rate and falling rate period. We observed that higher temperature reduced the drying time, indicating higher drying rates of jujubes. The experimental drying data of jujubes were used to fit ten different thin-layer models, then drying rate constants and coefficients of models tested were determined by nonlinear regression analysis using the Statistical Computer Program. As for all the drying models, the Weibull distribution model was superior and best predicted the experimental values. Therefore, this model can be used to facilitate dryer design and promote efficient dryer operation by simulation and optimization of the drying processes. The volumetric shrinkable coefficient of jujubes decreased as the drying air temperature increased.

  13. Microstructure of bidisperse ferrofluids in a thin layer

    Energy Technology Data Exchange (ETDEWEB)

    Minina, E. S., E-mail: alla2307@gmail.com; Muratova, A. B. [Ural Federal University, Department of Mathematical Physics (Russian Federation); Cerda, J. J. [Campus University de les Illes Balears, Institute for Cross-Disciplinary Physics and Complex Systems (Spain); Kantorovich, S. S., E-mail: sue.kantorovich@usu.ru [Ural Federal University, Department of Mathematical Physics (Russian Federation)

    2013-03-15

    In this work we present a characterization of the bidisperse ferrofluid microstructures that appear in thin layers of ferrofluid. These layers have been studied by a combination of Langevin dynamics simulations and density functional theory. Our results allow us to compare the microstructures that exist in quasi-two-dimensional ferrofluid nanolayers with the microstructures found in three-dimensional bidisperse ferrofluids. Furthermore, our results allow us to explain the influence of the geometry of the sample on the topology and size-distribution of the observed aggregates of magnetic nanoparticles.

  14. Atomic layer deposition of superparamagnetic and ferrimagnetic magnetite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yijun; Liu, Ming, E-mail: mingliu@mail.xjtu.edu.cn, E-mail: wren@mail.xjtu.edu.cn, E-mail: zye@sfu.ca; Ren, Wei, E-mail: mingliu@mail.xjtu.edu.cn, E-mail: wren@mail.xjtu.edu.cn, E-mail: zye@sfu.ca [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Yuepeng; Chen, Xing [Energy Systems Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Ye, Zuo-Guang, E-mail: mingliu@mail.xjtu.edu.cn, E-mail: wren@mail.xjtu.edu.cn, E-mail: zye@sfu.ca [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi' an Jiaotong University, Xi' an 710049 (China); Department of Chemistry and 4D LABS, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada)

    2015-05-07

    One of the key challenges in realizing superparamagnetism in magnetic thin films lies in finding a low-energy growth way to create sufficiently small grains and magnetic domains which allow the magnetization to randomly and rapidly reverse. In this work, well-defined superparamagnetic and ferrimagnetic Fe{sub 3}O{sub 4} thin films are successfully prepared using atomic layer deposition technique by finely controlling the growth condition and post-annealing process. As-grown Fe{sub 3}O{sub 4} thin films exhibit a conformal surface and poly-crystalline nature with an average grain size of 7 nm, resulting in a superparamagnetic behavior with a blocking temperature of 210 K. After post-annealing in H{sub 2}/Ar at 400 °C, the as-grown α−Fe{sub 2}O{sub 3} sample is reduced to Fe{sub 3}O{sub 4} phase, exhibiting a ferrimagnetic ordering and distinct magnetic shape anisotropy. Atomic layer deposition of magnetite thin films with well-controlled morphology and magnetic properties provides great opportunities for integrating with other order parameters to realize magnetic nano-devices with potential applications in spintronics, electronics, and bio-applications.

  15. A Dynamical Model for a Thin Layer of Granular Materials

    Institute of Scientific and Technical Information of China (English)

    MIAO Guo-Qing; SUI Lei; WEI Rong-Jue

    2001-01-01

    A dynamical model is presented for a thin layer of granular materials similar to that for shallow viscous fluids.We have obtained analytically the expressions for the "thermal expansion", dispersion relation, and dependence of instability onset on driving frequency and viscosity, which are in agreement with experiments. The numerical calculation for the nonlinear problem reproduces the experimental phenomena for a one-dimensional system.

  16. Spray Layer-by-Layer Assembled Clay Composite Thin Films as Selective Layers in Reverse Osmosis Membranes.

    Science.gov (United States)

    Kovacs, Jason R; Liu, Chaoyang; Hammond, Paula T

    2015-06-24

    Spray layer-by-layer assembled thin films containing laponite (LAP) clay exhibit effective salt barrier and water permeability properties when applied as selective layers in reverse osmosis (RO) membranes. Negatively charged LAP platelets were layered with poly(diallyldimethylammonium) (PDAC), poly(allylamine) (PAH), and poly(acrylic acid) (PAA) in bilayer and tetralayer film architectures to generate uniform films on the order of 100 nm thick that bridge a porous poly(ether sulfone) support to form novel RO membranes. Nanostructures were formed of clay layers intercalated in a polymeric matrix that introduced size-exclusion transport mechanisms into the selective layer. Thermal cross-linking of the polymeric matrix was used to increase the mechanical stability of the films and improve salt rejection by constraining swelling during operation. Maximum salt rejection of 89% was observed for the tetralayer film architecture, with an order of magnitude increase in water permeability compared to commercially available TFC-HR membranes. These clay composite thin films could serve as a high-flux alternative to current polymeric RO membranes for wastewater and brackish water treatment as well as potentially for forward osmosis applications. In general, we illustrate that by investigating the composite systems accessed using alternating layer-by-layer assembly in conjunction with complementary covalent cross-linking, it is possible to design thin film membranes with tunable transport properties for water purification applications.

  17. The collective motion of nematodes in a thin liquid layer

    CERN Document Server

    Gart, Sean; Jung, Sunghwan

    2010-01-01

    Many organisms live in confined fluidic environments such as the thin liquid layers on the skin of host organisms or in partially- saturated soil. We investigate the collective behaviour of nematodes in a thin liquid layer, which was first observed by Gray and Lissmann, [J. Exp. Biol. 41, 135 (1964)]. We show experimentally that nematodes confined by a thin liquid film come into contact and only separate again after some intervention. We attribute this collective motion to an attractive force between them arising from the surface tension of the layer and show that for nearby nematodes this force is typically stronger than the force that may be exerted by the nematodes' muscles. We believe this to be the first demonstration of the "Cheerios effect" acting on a living organism. However, we find that being grouped together does not significantly alter the body stroke and kinematic performance of the nematode: there are no statistically significant changes of the Strouhal number and the ratio of amplitude to wave...

  18. Effect of pirfenidone delivered using layer-by-layer thin film on excisional wound healing.

    Science.gov (United States)

    Mandapalli, Praveen Kumar; Labala, Suman; Bojja, Jagadeesh; Venuganti, Venkata Vamsi Krishna

    2016-02-15

    The aim of this study was to evaluate the effect of a new anti-fibrotic agent, pirfenidone (PFD), delivered using polyelectrolyte multilayer films on excisional wound healing. Polyelectrolyte multilayer films were prepared by layer-by-layer (LbL) sequential adsorption of chitosan and sodium alginate. The UV-spectrophotometer, FTIR and differential scanning calorimeter were used to characterize the LbL thin films. The PFD was entrapped within the LbL thin films and its effect on excisional wound healing was studied in C57BL/6. The total protein, collagen content and TGF-β expression within the wound tissue were determined after application of PFD using LbL thin films, chitosan hydrogel and polyethylene glycol hydrogel. UV-spectrophotometer and FTIR studies showed a sequential adsorption of chitosan and alginate polymer layers to form LbL thin films. The thickness of LbL thin films with 15 bilayers was found to be 15 ± 2 μm. HPLC analysis showed a PFD loading efficiency of 1.0 ± 0.1mg in 1cm(2) area of LbL thin film. In vivo wound healing studies in C57BL/6 mice showed an accelerated (<9 days) wound contraction after treatment with the PFD compared with blank LbL thin film and commercial povidone-iodine gel (12 days). The collagen content within the wound tissue was significantly (p<0.05) less after treatment with PFD compared with blank film application. Western blot analysis showed gradual decrease in TGF-β expression within the wound tissue after treatment with PFD. This study for the first time demonstrated that new anti-fibrotic agent PFD loaded in LbL thin films can be utilized for excisional wound healing. PMID:26723907

  19. Infrared analysis of thin layers by attenuated total reflection spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rochat, N.; Chabli, A.; Bertin, F.; Vergnaud, C.; Mur, P.; Petitdidier, S.; Besson, P

    2003-09-15

    Interests in infrared spectroscopy (IRS) have been stimulated by the increasing need for non-destructive surface characterization providing structural and chemical informations about the new materials used in microelectronic devices. Standard infrared spectroscopy of thin layers is limited because of its lack of sensitivity. The use of optical configurations such as the attenuated total reflection (ATR) allows to characterize nanometric layers. This paper will present the results of a study conducted for a better understanding of the capabilities and limitations of this technique. A theoretical analysis based on a perturbation method is used to elucidate the results of ATR measurements performed on silicon oxide layers of different thickness on silicon substrates. This analysis shows that the absorbance ATR spectrum in p polarization is the image of the layer energy loss function, under specific conditions. The exact ATR spectrum simulation using a matrix formalism showed that the straightforward interpretation in terms of the layer dielectric function is limited to a very narrow layer thickness range. The fitting process of the ATR spectrum is evaluated for the interpretation of experimental spectra obtained for the growth of chemical silicon oxide layers.

  20. Thin layer chromatographic separation of cobalt from nickel on impregnated silica gel layers:quantitative determination by digital image analysis%Thin layer chromatographic separation of cobalt from nickel on impregnated silica gel layers: quantitative determination by digital image analysis

    Institute of Scientific and Technical Information of China (English)

    P A MOHAMED NAJAR; R G SONALI; M T NIMJE; K V RAMANA RAO

    2012-01-01

    Thin layer chromatography (TLC) of cobalt and nickel has been performed on silica gel layers induced with alkali mediated cellulose extract.A novel combination of 10% aqueous solutions of Tween-20 and potassium thiocyanate in 1∶ 1 (v/v) was identified as the best mobile phase for the selective separation of Co2+ from Ni2+ on the impregnated Silica Gel G layers.The chromatographic characteristics of the cations were studied and the limits of detection as well as the limits of quantification for Co2+ and Ni2+ were determined.The quantitative estimation of the cations was achieved from the digital image analysis of respective chromatograms.The proposed quantitative method was successfully applied with 0-0.50% error for the determination of Co2+ from Ni2+ in spiked samples of bauxite,soil and rock containing common cations such as Al3+,Fe2+,Ti4+,Zn2+,Mn2+,Cu2+,Cr6+,Mg2+ etc.under the optimized chromatographic conditions.

  1. Reflection of infrared radiation from thin aluminium layers

    CERN Document Server

    Calatroni, Sergio

    2001-01-01

    The thermal shielding of the LHC magnets cryostats will make use of Multi-Layer Insulation. This is a sandwich of several Mylar (polyester) foils 6 µm thick coated with a thin film of aluminium, having a thickness of some 30 nm. The thickness of the aluminium film must be kept at a minimum to minimise lateral thermal conduction. The outer layer of this sandwich stays at a temperature of 20 K or below, and receives IR radiation from surfaces at 77 K (wavelength of 37.6 µm at the peak of blackbody radiation), which should be reflected with the highest efficiency. The minimum thickness for the aluminium layer to avoid transmission of the radiation can be calculated by making use of the skin effect theory, taking into account the changes in electrical properties that are due to the extremely low thickness of the film.

  2. Fracture Patterns Induced by Desiccation in a Thin Layer

    CERN Document Server

    Kitsunezaki, S

    1999-01-01

    We study a theoretical model of mud cracks, that is, the fracture patterns resulting from the contraction with drying in a thin layer of a mixture of granules and water. In this model, we consider the slip on the bottom of this layer and the relaxation of the elastic field that represents deformation of the layer. Analysis of the one-dimensional model gives results for the crack size that are consistent with experiments. We propose an analytical method of estimation for the growth velocity of a simple straight crack to explain the very slow propagation observed in actual experiments. Numerical simulations reveal the dependence of qualitative nature of the formation of crack patterns on material properties.

  3. Comparação das técnicas de cromatografia em camada delgada e ELISA na quantificação de aflatoxinas em amostras de milho Comparison of thin layer chromatography and ELISA techniques in the quantification of aflatoxins in corn samples

    Directory of Open Access Journals (Sweden)

    Marize Silva OLIVEIRA

    2000-12-01

    Full Text Available A comparação das técnicas de Enzyme Linked Immunosorbent Assay (ELISA e cromatografia em camada delgada (CCD por quantificação visual e densitométrica foi utilizada na determinação de aflatoxina total, em amostras de milho naturalmente contaminadas. Os teores de aflatoxina total encontrados pelas técnicas de CCD e ELISA, apresentaram maior freqüência na faixa de 0-30 mig/kg e acima de 300 mig/kg. Os resultados das amostras apresentaram coeficiente de variação concentrados abaixo de 20, 30 e 40% para a técnica de ELISA e CCD com quantificação densitométrica e visual, respectivamente. Os coeficientes de correlação foram altamente significativos para as relações entre as quantificações visual e densitométrica (r = 0,9219; t = 26,36; p Two methods, enzyme linked immunosorbent assay (ELISA and thin layer chromatography (TLC by visual and densitometric, were compared for determination of aflatoxins in corn samples. The highest incidence of total aflatoxin detected by those methods were ranged from 0-30 mug/kg and above 300 mug/kg. For aflatoxins B2, G1, G2 the levels were ranged from 0-30mug/kg. The samples results showed variation coefficient below of 20, 30 and 40% for ELISA and CCD with densitometric and visual quantification, respectively. The correlation coefficients were highly significative for the relation between visual quantification and densitometric (r = 0,9219; t = 28,36; p<0,001, ELISA and visual quantification (r =0,8277; t = 17,58; p< 0,001, ELISA e quantification densitometric (r = 0,7373; t=13,01; p< 0,001, in the total aflatoxin detemination of all corn samples. confirming the equivalence of the studied methods.

  4. Properties of Ultra-Thin Hafnium Oxide and Interfacial Layer Deposited by Atomic Layer Deposition

    Institute of Scientific and Technical Information of China (English)

    Taeho Lee; Young-Bae Kim; Kyung-Il Hong; Duck-Kyun Choi; Jinho Ahn

    2004-01-01

    Ultra-thin hafnium-oxide gate dielectric films deposited by atomic layer deposition technique using HfCl4 and H2O precursor on a hydrogen-terminated Si substrate were investigated. X-ray photoelectron spectroscopy indicates that the interface layer is Hf-silicate rather than phase separated Hf-silicide and silicon oxide structure. The Hf-silicate interfacial layer partially changes into SiOx after high temperature annealing, resulting in a complex HfO2-silicate-SiOx dielectric structure. Electrical measurements confirms that HfO2 on Si is stable up to 700 ℃ for 30 s under N2 ambient.

  5. A contribution to the determination of aflatoxin B1, quinine hydrochloride and L(+)-ascorbic acid in foodstuffs by quantitative in situ thin-layer chromatographic analysis

    NARCIS (Netherlands)

    Beljaars, P.R.

    1974-01-01

    The application of quantitative thin-layer chromatography (TLC) involving in situ spectrodensitometric measurements with a flying-spot densitometer is described in this study for the analysis of aflatoxin B 1 , quinine hydrochloride and L(+)-ascorbic acid (vitamin C

  6. Ion Exchange and Thin Layer Chromatographic Separation and Identification of Amino Acids in a Mixture: An Experiment for General Chemistry and Biotechnology Laboratories

    Science.gov (United States)

    Brunauer, Linda S.; Caslavka, Katelyn E.; Van Groningen, Karinne

    2014-01-01

    A multiday laboratory exercise is described that is suitable for first-year undergraduate chemistry, biochemistry, or biotechnology students. Students gain experience in performing chromatographic separations of biomolecules, in both a column and thin layer chromatography (TLC) format. Students chromatographically separate amino acids (AA) in an…

  7. Layer-by-layer thinning of two-dimensional MoS2 films by using a focused ion beam

    Science.gov (United States)

    Wang, Ding; Wang, Yuqiu; Chen, Xiaodong; Zhu, Yuankun; Zhan, Ke; Cheng, Hongbin; Wang, Xianying

    2016-02-01

    A layer-controlled two-dimensional (2D) molybdenum disulfide (MoS2) film with tunable bandgaps is highly desired for the fabrication of electronic/photoelectronic devices. In this work, we demonstrate that a focused ion beam (FIB) can be applied to thin MoS2 films layer-by-layer. The layer number can be controlled by simply changing the Ga+ beam exposure time and the thinning speed is about half a layer per second. OM, AFM, PL and Raman spectra were used to monitor the change of layer numbers and characterize the morphology, thickness, and homogeneity of MoS2 films. The FIB layer-by-layer thinning technology will establish a new methodology for rationally thinning all kinds of 2D layered materials.A layer-controlled two-dimensional (2D) molybdenum disulfide (MoS2) film with tunable bandgaps is highly desired for the fabrication of electronic/photoelectronic devices. In this work, we demonstrate that a focused ion beam (FIB) can be applied to thin MoS2 films layer-by-layer. The layer number can be controlled by simply changing the Ga+ beam exposure time and the thinning speed is about half a layer per second. OM, AFM, PL and Raman spectra were used to monitor the change of layer numbers and characterize the morphology, thickness, and homogeneity of MoS2 films. The FIB layer-by-layer thinning technology will establish a new methodology for rationally thinning all kinds of 2D layered materials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05768j

  8. Two approaches for enhancing the hydrogenation properties of palladium: Metal nanoparticle and thin film over layers

    Indian Academy of Sciences (India)

    Manika Khanuja; B R Mehta; S M Shivaprasad

    2008-11-01

    In the present study, two approaches have been used for enhancing the hydrogenation properties of Pd. In the first approach, metal thin film (Cu, Ag) has been deposited over Pd and hydrogenation properties of bimetal layer Cu (thin film)/Pd(thin film) and Ag(thin film)/Pd(thin film) have been studied. In the second approach, Ag metal nanoparticles have been deposited over Pd and hydrogenation properties of Ag (nanoparticle)/Pd (thin film) have been studied and compared with Ag(thin film)/Pd(thin film) bimetal layer system. The observed hydrogen sensing response is stable and reversible over a number of hydrogen loading and deloading cycles in both bimetallic systems. Alloying between Ag and Pd is suppressed in case of Ag(nanoparticle)/Pd(thin film) bimetallic layer on annealing as compared to Ag (thin film)/Pd(thin film).

  9. Thin-Layer Solutions of the Helmholtz and Related Equations

    KAUST Repository

    Ockendon, J. R.

    2012-01-01

    This paper concerns a certain class of two-dimensional solutions to four generic partial differential equations-the Helmholtz, modified Helmholtz, and convection-diffusion equations, and the heat conduction equation in the frequency domain-and the connections between these equations for this particular class of solutions.S pecifically, we consider thin-layer solutions, valid in narrow regions across which there is rapid variation, in the singularly perturbed limit as the coefficient of the Laplacian tends to zero.F or the wellstudied Helmholtz equation, this is the high-frequency limit and the solutions in question underpin the conventional ray theory/WKB approach in that they provide descriptions valid in some of the regions where these classical techniques fail.E xamples are caustics, shadow boundaries, whispering gallery, and creeping waves and focusing and bouncing ball modes.It transpires that virtually all such thin-layer models reduce to a class of generalized parabolic wave equations, of which the heat conduction equation is a special case. Moreover, in most situations, we will find that the appropriate parabolic wave equation solutions can be derived as limits of exact solutions of the Helmholtz equation.W e also show how reasonably well-understood thin-layer phenomena associated with any one of the four generic equations may translate into less well-known effects associated with the others.In addition, our considerations also shed some light on the relationship between the methods of matched asymptotic, WKB, and multiple-scales expansions. © 2012 Society for Industrial and Applied Mathematics.

  10. Obtaining shape memory alloy thin layer using PLD technique

    Directory of Open Access Journals (Sweden)

    Cimpoeşu N.

    2014-01-01

    Full Text Available Copper-based shape memory alloy (SMA was obtained through a classic melting method. The material was analyzed in heat treated and deformed states using scanning electrons microscopy (SEM, dilatometry (DIL, differential scanning calorimetry (DSC, dynamic mechanical analyzer (DMA and energy dispersive X-ray analyze (EDAX to establish the material microstructure, memory properties like martensitic transformation domain and rate or damping capacity. The material exhibits a good shape memory effect and high internal friction and it is proposed as target in a pulsed laser deposition (PLD process for obtaining thin films. The deposition process is described in this paper through presented experimental results on the layer.

  11. Collapse of molecularly thin lubricant layers between elastic substrates

    CERN Document Server

    Becker, T

    2003-01-01

    We investigated the dynamics of layering transitions and other structure formation processes in molecularly thin liquid films upon reducing the separation between two atomically smooth mica substrates. Using a newly developed surface forces apparatus with two-dimensional imaging capability, we followed the hydrodynamic processes during drainage with unprecedented precision. Depending on the substrate elasticity and the approach rate, drainage occurs either in a series of consecutive layering transitions or in a single step. In the latter case, nanoscopic amounts of liquid are trapped inside the contact area transiently. The experimental observations are explained qualitatively by combining hydrodynamic effects with elastic deformations of the substrates. Furthermore, we present evidence for anisotropy in the fluid dynamics induced by the lattice symmetry of the substrates.

  12. Process for the production of thin layers, preferably for a photovoltaic cell

    NARCIS (Netherlands)

    Nanu, M.; Meester, B.; Goossens, A.; Schoonman, J.

    2006-01-01

    The invention is directed to a process for the production of a thin layer, preferably for a photovoltaic cell, which cell has at least a first contact layer, a p-type semiconductor layer, an n-type semiconductor layer, or a combined p-type/n-type semiconductor layer, and a second contact layer, said

  13. Femtosecond pulsed laser deposition of biological and biocompatible thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Hopp, B. [Hungarian Academy of Sciences, University of Szeged, Research Group on Laser Physics, Dom ter 9, H-6720 Szeged (Hungary)]. E-mail: bhopp@physx.u-szeged.hu; Smausz, T. [Hungarian Academy of Sciences, University of Szeged, Research Group on Laser Physics, Dom ter 9, H-6720 Szeged (Hungary); Kecskemeti, G. [Department of Optics and Quantum Electronics, University of Szeged, Dom ter 9, H-6720 Szeged (Hungary); Klini, A. [Institute of Electronic Structure and Laser (I.E.S.L.), Foundation for Research and Technology-Hellas (F.O.R.T.H.), P.O. Box 1527, GR-711 10 Heraklion, Crete (Greece); Bor, Zs. [Department of Optics and Quantum Electronics, University of Szeged, Dom ter 9, H-6720 Szeged (Hungary)

    2007-07-31

    In our study we investigate and report the femtosecond pulsed laser deposition of biological and biocompatible materials. Teflon, polyhydroxybutyrate, polyglycolic-acid, pepsin and tooth in the form of pressed pellets were used as target materials. Thin layers were deposited using pulses from a femtosecond KrF excimer laser system (FWHM = 450 fs, {lambda} = 248 nm, f = 10 Hz) at different fluences: 0.6, 0.9, 1.6, 2.2, 2.8 and 3.5 J/cm{sup 2}, respectively. Potassium bromide were used as substrates for diagnostic measurements of the films on a FTIR spectrometer. The pressure in the PLD chamber was 1 x 10{sup -3} Pa, and in the case of tooth and Teflon the substrates were heated at 250 deg. C. Under the optimized conditions the chemical structure of the deposited materials seemed to be largely preserved as evidenced by the corresponding IR spectra. The polyglycolic-acid films showed new spectral features indicating considerable morphological changes during PLD. Surface structure and thickness of the layers deposited on Si substrates were examined by an atomic force microscopy (AFM) and a surface profilometer. An empirical model has been elaborated for the description of the femtosecond PLD process. According to this the laser photons are absorbed in the surface layer of target resulting in chemical dissociation of molecules. The fast decomposition causes explosion-like gas expansion generating recoil forces which can tear off and accelerate solid particles. These grains containing target molecules without any chemical damages are ejected from the target and deposited onto the substrate forming a thin layer.

  14. DETERMINATION OF CEFDITOREN PIVOXIL IN HUMAN PLASMA BY HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHIC METHOD

    Directory of Open Access Journals (Sweden)

    Dhoka Madhura Vishal

    2011-05-01

    Full Text Available A simple, rapid, sensitive high performance thin layer chromatography method for cefditoren pivoxil in human plasma using cephalexin as an internal standard has been developed and validated. The method enables to determine cefditoren pivoxil with minimum quantification limit 0.1µg ml-1 to 0.6 µg ml-1 having retention factor of 0.74±0.03. The sample preparation involves the simple protein precipitation technique using methanol as a precipitating agent. The determination was carried out on silica gel 60 F245 TLC plate with a mobile phase consisted of toluene: methanol: triethylamine (5:3.5:0.09 v/v/v. The wavelength selected was 250nm.

  15. The reflectivity of relativistic ultra-thin electron layers

    CERN Document Server

    Wu, Hui-Chun

    2008-01-01

    The coherent reflectivity of a dense, relativistic, ultra-thin electron layer is derived analytically for an obliquely incident probe beam. Results are obtained by two-fold Lorentz transformation. For the analytical treatment, a plane uniform electron layer is considered. All electrons move with uniform velocity under an angle to the normal direction of the plane; such electron motion corresponds to laser acceleration by direct action of the laser fields, as it is described in a companion paper. Electron density is chosen high enough to ensure that many electrons reside in a volume \\lambda_R^3, where \\lambda_R is the wavelength of the reflected light in the rest frame of the layer. Under these conditions, the probe light is back-scattered coherently and is directed close to the layer normal rather than the direction of electron velocity. An important consequence is that the Doppler shift is governed by \\gamma_x=(1-(V_x/c)^2)^{-1/2} derived from the electron velocity component V_x in normal direction rather th...

  16. Selective separation and determination of isoproterenol on thin layers of bismuth silicate ion-exchanger

    Institute of Scientific and Technical Information of China (English)

    Vanik GHOULIPOUR; Zahra HASSANKHANI-MAJD

    2015-01-01

    A simple and sensitive method for the separation and determination of isoproterenol from other do-ping drugs has been developed on thin layers of bismuth silicate,a synthetic inorganic ion exchanger as adsor-bent in thin layer chromatography(TLC). A mixture of methanol and 0. 1 mol/L formic acid(3:7,v/v)was employed as the mobile phase. The development time was 32 min. The quantitative measurement were per-formed with a Camag TLC Scanner-3 at wavelength(λ)of 410 nm. The isoproterenol recovery in this procedure was 98. 9%. The linear correlation coefficient was greater than 0. 987 1 and the relative standard deviation (RSD)was less than 0.94. The limit of detection(LOD)and limit of quantification(LOQ)were 7.7×10-7 mol/L and 3. 85 ×10-6 mol/L,respectively. This method has been applied in the determination of isoproterenol in dosage forms and in biological fluids.

  17. Selective separation and determination of isoproterenol on thin layers of bismuth silicate ion-exchanger.

    Science.gov (United States)

    Ghoulipour Vanik; Hassankhani-Majd Zahra

    2015-06-01

    A simple and sensitive method for the separation and determination of isoproterenol from other doping drugs has been developed on thin layers of bismuth silicate, a synthetic inorganic ion exchanger as adsorbent in thin layer chromatography (TLC). A mixture of methanol and 0.1 mol/L formic acid (3:7, v/v) was employed as the mobile phase. The development time was 32 min. The quantitative measurement were performed with a Camag TLC Scanner-3 at wavelength (λ) of 410 nm. The isoproterenol recovery in this procedure was 98.9%. The linear correlation coefficient was greater than 0. 987 1 and the relative standard deviation (RSD) was less than 0.94. The limit of detection (LOD) and limit of quantification ( LOQ) were 7.7 x 10(-7) mol/L and 3.85 x 10(-6) mol/L, respectively. This method has been applied in the determination of isoproterenol in dosage forms and in biological fluids.

  18. Investigation of thin polymer layers for biosensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Saftics, András; Agócs, Emil [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Fodor, Bálint [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Doctoral School of Physics, Faculty of Science, University of Pécs, 7624 Pécs, Ifjúság útja 6 (Hungary); Patkó, Dániel; Petrik, Péter [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Doctoral School of Molecular- and Nanotechnologies, Faculty of Information Technology, University of Pannonia, H-8200 Egyetem u.10, Veszprém (Hungary); Kolari, Kai; Aalto, Timo [VTT Technical Research Centre of Finland, PL 1000, Tietotie 3, 02044 Espoo (Finland); Fürjes, Péter [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Horvath, Robert [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Doctoral School of Molecular- and Nanotechnologies, Faculty of Information Technology, University of Pannonia, H-8200 Egyetem u.10, Veszprém (Hungary); Kurunczi, Sándor, E-mail: kurunczi.sandor@ttk.mta.hu [Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences–H-1121 Budapest (Hungary); Doctoral School of Molecular- and Nanotechnologies, Faculty of Information Technology, University of Pannonia, H-8200 Egyetem u.10, Veszprém (Hungary)

    2013-09-15

    Novel biosensors made of polymers may offer advantages over conventional technology such as possibility of mass production and tunability of the material properties. With the ongoing work on the polymer photonic chip fabrication in our project, simple model samples were tested parallel for future immobilization and accessing conditions for applications in typical aqueous buffers. The model samples consist of a thin, high refractive index polyimide film on top of TEOS on Si wafer. These model samples were measured by in situ spectroscopic ellipsometry using different aqueous buffers. The experiments revealed a high drift in aqueous solutions; the drift in the ellipsometric parameters (delta, psi) can be evaluated and presented as changes in thickness and refractive index of the polyimide layer. The first molecular layer of immobilization is based on polyethyleneimine (PEI). The signal for the PEI adsorption was detected on a stable baseline, only after a long conditioning. The stability of polyimide films in aqueous buffer solutions should be improved toward the real biosensor application. Preliminary results are shown on the possibilities to protect the polyimide. Optical Waveguide Lightmode Spectroscopy (OWLS) has been used to demonstrate the shielding effect of the thin TiO{sub 2} adlayer in biosensor applications.

  19. Kinetics and morphology of electrochemical vapour deposited thin zirconia/yttria layers on porous substrates

    NARCIS (Netherlands)

    Brinkman, H.W.; Meijerink, J.; Vries, de K.J.; Burggraaf, A.J.

    1996-01-01

    By means of electrochemical vapour deposition (EVD), it is possible to grow thin (0.5-5 µm), dense zirconia/yttria layers on porous ceramic substrates. Kinetics of the EVD process, morphology and oxygen permeation properties of the grown layers are investigated. Very thin (~ 0.5 µm) layers are grown

  20. Intoxicação em cães e gatos: diagnóstico toxicológico empregando cromatografia em camada delgada e cromatografia líquida de alta pressão com detecção ultravioleta em amostras estomacais Intoxication in dogs and cats: toxicological diagnosis using thin layer chromatography and high pressure liquid chromatography with ultraviolet detection in stomach samples

    Directory of Open Access Journals (Sweden)

    Rachel Picada Bulcão

    2010-05-01

    óticos mais envolvidos nessas intoxicações.The pesticides and rodenticides are responsible for several human and animal intoxications. Preliminary data suggest that the illegal use of these compounds to poison small animals is a common practice in the central region of the Rio Grande do Sul state. The Laboratory of Toxicology received samples, of cases in which the main suspected cause of death is poisoning by pesticides or exogenous rodenticides (licit and illicit. The aim of this study was show the survey of small animals poisoned and analyzed by LATOX during the period of 2004 to 2008 identifying the xenobiotics by optimized analytical methods, including screening by thin-layer chromatography (TLC and a possible confirmation by high performance liquid chromatography - ultraviolet detection (HPLC-UV. In this period 68 samples were analyzed from small poisoned animals. The biological samples analyzed were stomach and stomach content and the TLC permitted carbamates, warfarin and stricnine identification. This proved to be an efficient and adequate technique for this purpose, relatively fast, inexpensive and with low matrix interference. The screening by HPLC for N-methyl carbamates was also realized: aldicarb, carbaryl, carbofuran and propoxur. The analysis showed that the main toxic agent found was aldicarb (chumbinho, responsible for 39.7% of poisoning (27 cases, followed by stricnine (6 cases, warfarin (3 cases and sodium monofluoracetate (1 case. Thus, the 'chumbinho' was the main agent involved in dogs and cats poisoning in the central region of the state, during the analyzed period. The analytical methods TLC and HPLC can be used efficiently in laboratorial routine for identification and confirmation of xenobiotics involved in these poisonings.

  1. Intralaboratory optimization and validation of a method for patulin determination in grapes by Thin-Layer Chromatography Otimização e validação intralaboratorial de método para a determinação de patulina em uva por Cromatografia em Camada Delgada

    Directory of Open Access Journals (Sweden)

    Renata Cabrera de Oliveira

    2007-06-01

    Full Text Available The aim of this work was to optimize and validate, by intralaboratorial procedures, a method for the determination of patulin in grapes by thin-layer chromatography. The steps of extraction, cleanup, detection and quantification were optimized. For the validation of the method, recovery assays with standard solutions and artificially contaminated samples were carried out. The mean recovery and the variation coefficient were 65.4% and 7.58%, respectively. The optimized conditions were: 50 mL of grape juice, three extraction stages (with 100 mL of ethyl acetate in the first stage and 50 mL in second and third stages, and 100 µL of ethanol to solubilize the extract. The solvent-system used was toluene - ethyl acetate - formic acid (6:3:1, and 0.5% MBTH in 5% formic acid was sprayed on the plates to intensify the fluorescence. The visual detection and quantification limits were 7.44 ng and 15.87 µg.kg-1, respectively. The optimized and validated method demonstrated sufficient efficiency for adoption in the monitoring of patulin in grape.O objetivo deste trabalho foi otimizar e validar, por procedimentos intralaboratoriais, um método de determinação de patulina em uva por cromatografia em camada delgada. Foram realizados testes de otimização das etapas de extração, limpeza, detecção e quantificação. Para validação do método foram realizados ensaios de recuperação com soluções padrões e amostras artificialmente contaminadas. A recuperação e o coeficiente de variação foram 65,4% e 7,58%, respectivamente. As condições otimizadas foram: 50 mL do suco da uva; três etapas de extração, 100 mL de acetato de etila na primeira etapa e 50 mL na segunda e terceira etapas; 100 µL de etanol para solubilizar o extrato; a fase móvel tolueno-acetato de etila-ácido fórmico (6:3:1 e o revelador o MBTH 0,5% em ácido fórmico 5%. O limite de detecção visual foi de 7,44 ng e o de quantificação de 15,87 µg/kg. O método otimizado e

  2. Determinação de daidzeína, genisteína e gliciteína em cápsulas de isoflavonas por cromatografia em camada delgada (CCD e cromatografia líquida de alta eficiência (CLAE Determination of daidzein, genistein and glycitein in isoflavone capsules by thin layer chromatography (TLC and high performance liquid chromatography (HPLC

    Directory of Open Access Journals (Sweden)

    Isabela da Costa César

    2007-12-01

    isoflavone capsules, carried out by high performance liquid chromatography (HPLC, showed high variation in the content of the three aglycones, after acid hydrolysis. The contents varied in the following way, in the 18 batches of evaluated capsules: daidzein (13.34 to 76.20 mg/capsule, genistein (0.61 to 27.18 mg/capsule and glycitein (0.49 to 8.80 mg/capsule.

  3. Tensile strength of thin resin composite layers as a function of layer thickness.

    Science.gov (United States)

    Alster, D; Feilzer, A J; De Gee, A J; Davidson, C L

    1995-11-01

    As a rule, cast restorations do not allow for free curing contraction of the resin composite luting cement. In a rigid situation, the resulting contraction stress is inversely proportional to the resin layer thickness. Adhesive technology has demonstrated, however, that thin joints may be considerably stronger than thicker ones. To investigate the effects of layer thickness and contraction stress on the tensile strength of resin composite joints, we cured cylindrical samples of a chemically initiated resin composite (Clearfil F2) in restrained conditions and subsequently loaded them in tension. The samples had a diameter of 5.35 mm and thicknesses of 50, 100, 200, 300, 400, 500, 600, and 700 microns, 1.4 mm, or 2.7 mm. None of the samples fractured due to contraction stress prior to tensile loading. Tensile strength decreased gradually from 62 +/- 2 MPa for the 50-microns layer to 31 +/- 4 MPa for the 2.7-mm layer. The failures were exclusively cohesive in resin for layers between 50 and 400 microns thick. Between 500 and 700 microns, the failures were cohesive or mixed adhesive/cohesive, while the 1.4- and 2.7-mm layers always failed in a mixed adhesive/cohesive mode. For the resin composite tested, the contraction stress did not endanger the cohesive strength. It was concluded that if adhesion to tooth structure were improved, thinner adhesive joints might enhance the clinical success of luted restorations.

  4. Thin Layer Chromatographic Analysis of Beta-Lactam Antibiotics

    Directory of Open Access Journals (Sweden)

    Gabriel Hancu

    2013-08-01

    Full Text Available Purpose: The paper describes some thin layer chromatographic procedures that allow simple and rapid separation and identification of penicillins and cephalosporins from complex mixtures. Methods: Using silicagel GF254 as stationary phase and selecting different mobile phases we succeeded in the separation of the studied beta-lactamins. Our aim was not only to develop a simple, rapid and efficient method for their separation but also the optimization of the analytical conditions. Results: No system will separate all the beta-lactams, but they could be identified when supplementary information is used from color reactions and/or by using additional chromatographic systems. Conclusions: The right combination of solvent system and detection method allows the identification of the studied penicillins and cephalosporins and can be successfully used in the preliminary analysis beta-lactam antibiotics.

  5. Atmospheric corrosion evaluation of galvanised steel by thin layer activation

    International Nuclear Information System (INIS)

    The release of certain metals, such as zinc, from outdoor constructions due to atmospheric corrosion is of some concern. For risk assessments the evaluation of the amount of released metal is of importance. Various methods can be used to study the release of metals. These include those using radiotracers, such as thin layer activation (TLA). To verify the reliability of TLA with respect to conventional techniques in the evaluation of atmospheric corrosion, galvanised steel was exposed to a mild marine environment. The amount of zinc in the corrosion products, released through artificial leaching, at different time intervals was evaluated by TLA and atomic absorption spectroscopy (AAS). A good correlation between the results was found indicating the feasibility of TLA for these release studies

  6. Measurement of a thin layers thickness using independent component analysis of ground penetrating radar data

    Institute of Scientific and Technical Information of China (English)

    LI Xiang-tang; ZHANG Xiao-ning; WANG Duan-yi

    2008-01-01

    To detect overlapped echoes due to the thin pavement layers, we present a thickness measurement approach for the very thin layer of pavement structures. The term "thin" is relative to the incident wavelength or pulse. By means of independent component analysis of noisy signals received by a single radar sensor, the over-lapped echoes can be successfully separated. Once the echoes from the top and bottom side of a thin layer have been separated, the time delay and the layer thickness determination follow immediately. Results of the simula-tion and real data re fy the feasibility of the presented method.

  7. KINETICS OF THIN LAYER DRYING OF POULTRY MANURE

    Directory of Open Access Journals (Sweden)

    A. E. Ghaly

    2012-01-01

    Full Text Available The poultry industry is one of the largest and fastest growing sectors of livestock production in the world. The estimated 2010 world flock was over 18 billion birds with a yearly manure output of 22 million tonnes. Storage and disposal of raw poultry manure has become an environmental problem because of the associated air, water and soil pollution. Environmental and health problems such as odor and pathogens that may arise during and after land application of raw manure can be eliminated by drying. Dried manure can be utilized as a soil conditioner to improve soil tilth and reduce the problems associated with soil compaction and as a feed for ruminants because of its high nitrogen content. The aim of this study was to investigate the kinetics of thin layer drying of poultry manure and evaluate the effects of drying with heated air on the chemical and biological properties of manure. The effects of temperature and depth of manure layer were evaluated. The profile of the moisture content of poultry manure followed an exponential decay curve. The moisture decay constant was affected by the drying temperature and the depth of the manure layer. At the three temperature levels studied, the time required to dry poultry manure in 1 cm-deep layer was the least, followed by 2 and 3 cm-deep layers, respectively. The diffusion coefficient increased with both temperature and depth of drying layer, but did not show a linear increase with either variable. The optimum depth for drying manure (at which the highest drying effectiveness occurred was 3 cm. Drying manure at 40-60°C resulted in the loss of 44-55% of the total Kjeldahl nitrogen, with losses increasing with both the temperature and depth of manure. The pH of the manure decreased from the initial value of 8.4 before drying to about 6.6 after drying. The odor analysis indicated that dried poultry manure did not have an offensive odor. Drying achieved 65.3 and 69.3% reductions in odor intensity and

  8. Ion source for layer-by-layer analysis of thin films

    International Nuclear Information System (INIS)

    A structure of the ion source for the secondary-ion mass spectrometer, used for layer-by-layer analysis of thin films, is described. The base of the source is a set of metal rings calibrated by the internal diameter. All electrodes of the source are installed inside these rings. Rings and electrodes are made of stainless steel. To produce ions in the source, one of two accessory ionizers is used. The Penning ionizer with a cold cathode is used, when it is neccessary to obtain a constant maximum current density on a target (the regime of the layer-by-layer analysis). A set of rings, made of the Sm+Co alloy, serves as an anode and a magnetic system for the ionizer. Cathodes are made of stainless steel. The ionizer with a filament is used, when operating at the regime of beam ion current deep control. In this case beam current is controlled by changing the gas flow through the ionizer or by changing the cathode emission current, maximum value of which constitutes 5 mA. At the accelerating voltage of 5 kV and the gas flow rate of 10-4 l x Torr/s the above ion source allows to get the ion beam of 0.5 mm in diameter with the current of 1 μA at the target placed at the distance of 50 mm from the outlet. On the basis of the given layer-by-layer analysis results of the B distribution in Si, the conclusion is made that the ion beam scanning into raster and detection of ions extracted from beam central part, allows to increase essentially the spectrometer layer-by-layer resolution

  9. Integrated measurements of acoustical and optical thin layers I: Vertical scales of association

    Science.gov (United States)

    Benoit-Bird, Kelly J.; Moline, Mark A.; Waluk, Chad M.; Robbins, Ian C.

    2010-01-01

    This study combined measurements from multiple platforms with acoustic instruments on moorings and on a ship and optics on a profiler and an autonomous underwater vehicle (AUV) to examine the relationships between fluorescent, bioluminescent, and acoustically scattering layers in Monterey Bay during nighttime hours in July and August of 2006 and May of 2008. We identified thin bioluminescent layers that were strongly correlated with acoustic scattering at the same depth but were part of vertically broad acoustic features, suggesting layers of unique composition inside larger biomass features. These compositional thin layers nested inside larger biomass features may be a common ecosystem component and are likely to have significant ecological impacts but are extremely difficult to identify as most approaches capable of the vertical scales of measurement necessary for the identification of sub-meter scale patterns assess bulk properties rather than specific layer composition. Measurements of multiple types of thin layers showed that the depth offset between thin phytoplankton and zooplankton layers was highly variable with some layers found at the same depth but others found up to 16 m apart. The vertical offset between phytoplankton and zooplankton thin layers was strongly predicted by the fraction of the water column fluorescence contained within a thin phytoplankton layer. Thin zooplankton layers were only vertically associated with thin phytoplankton layers when the phytoplankton in a layer accounted for more than about 18-20% of the water column chlorophyll. Trophic interactions were likely occurring between phytoplankton and zooplankton thin layers but phytoplankton thin layers were exploited by zooplankton only when they represented a large fraction of the available phytoplankton, suggesting zooplankton have some knowledge of the available food over the entire water column. The horizontal extent of phytoplankton layers, discussed in the second paper in this

  10. Symmetrical periods used as matching layers in multilayer thin film design

    Institute of Scientific and Technical Information of China (English)

    Dan Wang; Zhengxiu Fan; Jianbing Huang; Jun Bi; Yingjian Wang

    2006-01-01

    Properties of symmetrical layers as matching layers in multilayer thin film design were analyzed. Acalculation method was presented to derive parameters of desired equivalent refractive index. A harmonicbeam splitter was designed and fabricated to test this matching method.

  11. Thin Layer Sensory Cues Affect Antarctic Krill Swimming Kinematics

    Science.gov (United States)

    True, A. C.; Webster, D. R.; Weissburg, M. J.; Yen, J.

    2013-11-01

    A Bickley jet (laminar, planar free jet) is employed in a recirculating flume system to replicate thin shear and phytoplankton layers for krill behavioral assays. Planar laser-induced fluorescence (LIF) and particle image velocimetry (PIV) measurements quantify the spatiotemporal structure of the chemical and free shear layers, respectively, ensuring a close match to in situ hydrodynamic and biochemical conditions. Path kinematics from digitized trajectories of free-swimming Euphausia superba examine the effects of hydrodynamic sensory cues (deformation rate) and bloom level phytoplankton patches (~1000 cells/mL, Tetraselamis spp.) on krill behavior (body orientation, swimming modes and kinematics, path fracticality). Krill morphology is finely tuned for receiving and deciphering both hydrodynamic and chemical information that is vital for basic life processes such as schooling behaviors, predator/prey, and mate interactions. Changes in individual krill behavior in response to ecologically-relevant sensory cues have the potential to produce population-scale phenomena with significant ecological implications. Krill are a vital trophic link between primary producers (phytoplankton) and larger animals (seabirds, whales, fish, penguins, seals) as well as the subjects of a valuable commercial fishery in the Southern Ocean; thus quantifying krill behavioral responses to relevant sensory cues is an important step towards accurately modeling Antarctic ecosystems.

  12. Graphene oxide monolayers as atomically thin seeding layers for atomic layer deposition of metal oxides

    Science.gov (United States)

    Nourbakhsh, Amirhasan; Adelmann, Christoph; Song, Yi; Lee, Chang Seung; Asselberghs, Inge; Huyghebaert, Cedric; Brizzi, Simone; Tallarida, Massimo; Schmeißer, Dieter; van Elshocht, Sven; Heyns, Marc; Kong, Jing; Palacios, Tomás; de Gendt, Stefan

    2015-06-01

    Graphene oxide (GO) was explored as an atomically-thin transferable seed layer for the atomic layer deposition (ALD) of dielectric materials on any substrate of choice. This approach does not require specific chemical groups on the target surface to initiate ALD. This establishes GO as a unique interface which enables the growth of dielectric materials on a wide range of substrate materials and opens up numerous prospects for applications. In this work, a mild oxygen plasma treatment was used to oxidize graphene monolayers with well-controlled and tunable density of epoxide functional groups. This was confirmed by synchrotron-radiation photoelectron spectroscopy. In addition, density functional theory calculations were carried out on representative epoxidized graphene monolayer models to correlate the capacitive properties of GO with its electronic structure. Capacitance-voltage measurements showed that the capacitive behavior of Al2O3/GO depends on the oxidation level of GO. Finally, GO was successfully used as an ALD seed layer for the deposition of Al2O3 on chemically inert single layer graphene, resulting in high performance top-gated field-effect transistors.Graphene oxide (GO) was explored as an atomically-thin transferable seed layer for the atomic layer deposition (ALD) of dielectric materials on any substrate of choice. This approach does not require specific chemical groups on the target surface to initiate ALD. This establishes GO as a unique interface which enables the growth of dielectric materials on a wide range of substrate materials and opens up numerous prospects for applications. In this work, a mild oxygen plasma treatment was used to oxidize graphene monolayers with well-controlled and tunable density of epoxide functional groups. This was confirmed by synchrotron-radiation photoelectron spectroscopy. In addition, density functional theory calculations were carried out on representative epoxidized graphene monolayer models to correlate the

  13. Proteins at fluid interfaces: adsorption layers and thin liquid films.

    Science.gov (United States)

    Yampolskaya, Galina; Platikanov, Dimo

    2006-12-21

    A review in which many original published results of the authors as well as many other papers are discussed. The structure and some properties of the globular proteins are shortly presented, special accent being put on the alpha-chymotrypsin (alpha-ChT), lysozyme (LZ), human serum albumin (HSA), and bovine serum albumin (BSA) which have been used in the experiments with thin liquid films. The behaviour of protein adsorption layers (PAL) is extensively discussed. The dynamics of PAL formation, including the kinetics of adsorption as well as the time evolution of the surface tension of protein aqueous solutions, are considered. A considerable place is devoted to the surface tension and adsorption isotherms of the globular protein solutions, the simulation of PAL by interacting hard spheres, the experimental surface tension isotherms of the above mentioned proteins, and the interfacial tension isotherms for the protein aqueous solution/oil interface. The rheological properties of PAL at fluid interfaces are shortly reviewed. After a brief information about the experimental methods for investigation of protein thin liquid (foam or emulsion) films, the properties of the protein black foam films are extensively discussed: the conditions for their formation, the influence of the electrolytes and pH on the film type and stability, the thermodynamic properties of the black foam films, the contact angles film/bulk and their dynamic hysteresis. The next center of attention concerns some properties of the protein emulsion films: the conditions for formation of emulsion black films, the formation and development of a dimpling in microscopic, circular films. The protein-phospholipid mixed foam films are also briefly considered.

  14. Using thin metal layers on composite structures for shielding the electromagnetic pulse caused by nearby lightning

    NARCIS (Netherlands)

    Blaj, M.A.; Buesink, F.J.K.; Damstra, G.C.; Leferink, F.B.J.

    2011-01-01

    Electronic systems in composite structures could be vulnerable to the (dominant magnetic) field caused by a lightning strike, because only thin layers of metal can be used on composite structures. Thin layers result in a very low shielding effectiveness against magnetic fields. Many experiments usin

  15. Design of step composition gradient thin film transistor channel layers grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Cheol Hyoun; Hee Kim, So; Gu Yun, Myeong; Koun Cho, Hyung, E-mail: chohk@skku.edu [School of Advanced Materials Science and Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2014-12-01

    In this study, we proposed the artificially designed channel structure in oxide thin-film transistors (TFTs) called a “step-composition gradient channel.” We demonstrated Al step-composition gradient Al-Zn-O (AZO) channel structures consisting of three AZO layers with different Al contents. The effects of stacking sequence in the step-composition gradient channel on performance and electrical stability of bottom-gate TFT devices were investigated with two channels of inverse stacking order (ascending/descending step-composition). The TFT with ascending step-composition channel structure (5 → 10 → 14 at. % Al composition) showed relatively negative threshold voltage (−3.7 V) and good instability characteristics with a reduced threshold voltage shift (Δ 1.4 V), which was related to the alignment of the conduction band off-set within the channel layer depending on the Al contents. Finally, the reduced Al composition in the initial layer of ascending step-composition channel resulted in the best field effect mobility of 4.5 cm{sup 2}/V s. We presented a unique active layer of the “step-composition gradient channel” in the oxide TFTs and explained the mechanism of adequate channel design.

  16. Effect of the haematocrit layer geometry on Plasmodium falciparum static thin-layer in vitro cultures

    Directory of Open Access Journals (Sweden)

    López Daniel

    2008-10-01

    Full Text Available Abstract Background In vitro cultivation of Plasmodium falciparum is usually carried out through the continuous preservation of infected erythrocytes deposited in static thin layers of settled haematocrit. This technique, called the candle-jar method, was first achieved by Trager and Jensen in 1976 and has undergone slight modifications since then. However, no systematic studies concerning the geometry of the haematocrit layer have been carried out. In this work, a thorough investigation of the effects of the geometric culturing conditions on the parasite's development is presented. Methods Several experimental trials exploring different settings have been carried out, covering haematocrit layer depths that ranged from 6 mm to 3 mm and separation between the walls of the culturing device that ranged from 7.5 mm to 9 mm. The obtained results have been analysed and compared to different system-level models and to an Individual-Based Model. Conclusion In line with the results, a mechanism governing the propagation of the infection which limits it to the vicinity of the interface between the haematocrit layer and the culture medium is deduced, and the most appropriate configurations are proposed for further experimental assays.

  17. Note: Automatic layer-by-layer spraying system for functional thin film coatings

    Science.gov (United States)

    Seo, Seongmin; Lee, Sangmin; Park, Yong Tae

    2016-03-01

    In this study, we have constructed an automatic spray machine for producing polyelectrolyte multilayer films containing various functional materials on wide substrates via the layer-by-layer (LbL) assembly technique. The proposed machine exhibits advantages in terms of automation, process speed, and versatility. Furthermore, it has several features that allow a fully automated spraying operation, such as various two-dimensional spraying paths, control of the flow rate and operating speed, air-assist fan-shaped twin-fluid nozzles, and an optical display. The robot uniformly sprays aqueous mixtures containing complementary (e.g., oppositely charged, capable of hydrogen bonding, or capable of covalent bonding) species onto a large-area substrate. Between each deposition of opposite species, samples are spray-rinsed with deionized water and blow-dried with air. The spraying, rinsing, and drying areas and times are adjustable by a computer program. Twenty-bilayer flame-retardant thin films were prepared in order to compare the performance of the spray-assisted LbL assembly with a sample produced by conventional dipping. The spray-coated film exhibited a reduction of afterglow time in vertical flame tests, indicating that the spray-LbL technique is a simple method to produce functional thin film coatings.

  18. The effect of solvent grade on thin layer chromatographic analysis of writing inks.

    Science.gov (United States)

    Barker, Julia; Ramotowski, Robert; Nwokoye, Jennie

    2016-09-01

    The effects on the separation of writing ink dyes and the repeatability of the Rf values from using different grades of chemicals used in solvent system I (SSI) and solvent system II (SSII) for thin-layer chromatographic (TLC) ink analysis were studied. Solvent system I consists of a 70:35:30 mixture of ethyl acetate, ethanol, and water. Solvent system II consists of a 50:10:15 mixture of ethanol, water, and n-butanol. Since 1991, the ASTM International Guideline E 1422 has recommended that the purity of solvents should be "reagent grade" and that water quality should be "distilled or equivalent." A total of 25 blue and 25 black inks were selected for analysis. Thirteen of each color ink were ballpoint and the remainder were non-ballpoint. The observations show that there is a solvent grade effect on both the separation and clarity of the ink dyes and the repeatability of their Rf values. These results indicate that the grades and manufacturers of solvents used in solvent systems for thin-layer chromatography must be consistent. This is especially critical for searching TLC plates against those from a large ink library in casework. Overall, the combination of solvents that produced the best results for solvent system I consisted of denatured ethanol, HPLC grade water, and ACS grade ethyl acetate. There was no consensus for the best combination of solvent grades for solvent system II; however, it was shown that different grades did have an effect on the separation of ink components.

  19. Junction conditions in quadratic gravity: thin shells and double layers

    CERN Document Server

    Reina, Borja; Vera, Raül

    2015-01-01

    The junction conditions for the most general gravitational theory with a Lagrangian containing terms quadratic in the curvature are derived. We include the cases with a possible concentration of matter on the joining hypersurface -termed as thin shells, domain walls or braneworlds in the literature- as well as the proper matching conditions where only finite jumps of the energy-momentum tensor are allowed. In the latter case we prove that the matching conditions are more demanding than in General Relativity. In the former case, we show that generically the shells/domain walls are of a new kind because they possess, in addition to the standard energy-momentum tensor, a double layer energy-momentum contribution which actually induces an external energy flux vector and an external scalar pressure/tension on the shell. We prove that all these contributions are necessary to make the entire energy-momentum tensor divergence-free, and we present the field equations satisfied by these energy-momentum quantities. The ...

  20. Somatic Embryogenesis of Lilium from Microbulb Transverse Thin Cell Layers.

    Science.gov (United States)

    Marinangeli, Pablo

    2016-01-01

    A reliable somatic embryogenesis protocol is a prerequisite for application of other plant biotechniques. Several protocols were reported for genus Lilium, with variable success. Between them, transverse Thin Cell Layers (tTCL) were used efficiently to induce indirect somatic embryogenesis of Lilium. Somatic embryogenesis potential is dependent on the genotype, explant, and culture medium composition, especially as for plant growth regulators and environmental conditions. Usually, the process comprises three phases: embryogenic callus induction, embryogenic callus proliferation and somatic embryo germination. Somatic embryo germination can be achieved in light or dark. In the first case, complete plantlets are formed, with green leaves and pseudobulb in the base. In darkness, microbulbs are formed from single somatic embryos or clusters. A last phase of microbulb enlargement allows plantlets or microbulbs to increase their biomass. These enlarged microbulbs do not need special acclimatization conditions when transferred to soil and quickly produce sturdy plants. This chapter describes a protocol for somatic embryogenesis of Lilium using tTCL from microbulbs.

  1. The Thin-Layer Modelling of Tomato Drying Process

    Directory of Open Access Journals (Sweden)

    Kamil Sacilik

    2007-12-01

    Full Text Available In this study thin-layer drying characteristics of tomato were investigated using a hot air convective dryer at a constant airflow velocity of 0.8 m s-1 and air temperature in the range of 50-70°C. The experimental drying data were fitted to the four well-known drying models i.e. the Page, Henderson and Pabis, logarithmic and two term models. Th e statistical validity of fit was measured using the coefficient of determination, mean relative percent deviation, root mean square error and reduced chi-square. Of all four models, the logarithmic model proved to be the best for predicting drying behaviour of tomato with values of coefficient of determination R2 greater than 0.99. The effective diffusivity was determined to be in the range of 2.56-4.28x10-9 m2 s-1 for nontreated samples and 4.29-6.28x10-9 m2 s-1 for blanched ones in the temperature range of 50-70°C. The temperature dependence of the effective diffusivity was described by the Arrhenius-type relationship. The activation energy values for non-treated and blanched samples were 23.73 and 17.55 kJ mol-1, respectively. Also, air temperature and pre-treatment affected the quality parameters of dried tomato.

  2. Mathematical Modeling of Thin Layer Microwave Drying of Taro Slices

    Science.gov (United States)

    Kumar, Vivek; Sharma, H. K.; Singh, K.

    2016-03-01

    The present study investigated the drying kinetics of taro slices precooked in different medium viz water (WC), steam (SC) and Lemon Solution (LC) and dried at different microwave power 360, 540 and 720 W. Drying curves of all precooked slices at all microwave powers showed falling rate period along with a very short accelerating period at the beginning of the drying. At all microwave powers, higher drying rate was observed for LC slices as compared to WC and SC slices. To select a suitable drying curve, seven thin-layer drying models were fitted to the experimental data. The data revealed that the Page model was most adequate in describing the microwave drying behavior of taro slices precooked in different medium. The highest effective moisture diffusivity value of 2.11 × 10-8 m2/s was obtained for LC samples while the lowest 0.83 × 10-8 m2/s was obtained for WC taro slices. The activation energy (E a ) of LC taro slices was lower than the E a of WC and SC taro slices.

  3. Characterization of Thin Layer Hot Air Drying of Celery Root

    Directory of Open Access Journals (Sweden)

    Xiaohong Wei

    2015-08-01

    Full Text Available The hot air drying characteristics of celery root were evaluated in a laboratory scale dryer at the drying temperatures of 50, 60, 70 and 80°C. The effect of hot air drying on drying time, drying rate, moisture content, moisture ratio and effective moisture diffusivity of celery root was investigated. Fifteen thin layer drying models were fitted by using experimental drying data. The fitting effect of model predictions was evaluated by using the values of coefficient of determination, sum squared error, root mean square error and chi-square. The results showed fitting accuracy of model 15 (Hii et al.,2009 gave a better fit for all drying conditions applied. The average values of effective moisture diffusivities of celery root ranged from 1.957×10-9 to 9.016×10-9 within the given drying temperature range. With in a certain temperature range (50-70°C, the average effective moisture diffusivities of celery root increased with increased temperature. The activation energy was estimated as 21.817 KJ/mol using an exponential expression based on the Arrhenius equation.

  4. Ultra-thin layer packaging for implantable electronic devices

    Science.gov (United States)

    Hogg, A.; Aellen, T.; Uhl, S.; Graf, B.; Keppner, H.; Tardy, Y.; Burger, J.

    2013-07-01

    State of the art packaging for long-term implantable electronic devices generally uses reliable metal and glass housings; however, these are limited in the miniaturization potential and cost reduction. This paper focuses on the development of biocompatible hermetic thin-film packaging based on poly-para-xylylene (Parylene-C) and silicon oxide (SiOx) multilayers for smart implantable microelectromechanical systems (MEMS) devices. For the fabrication, a combined Parylene/SiOx single-chamber deposition system was developed. Topological aspects of multilayers were characterized by atomic force microscopy and scanning electron microscopy. Material compositions and layer interfaces were analyzed by Fourier transform infrared spectrometry and x-ray photoelectron spectroscopy. To evaluate the multilayer corrosion protection, water vapor permeation was investigated using a calcium mirror test. The calcium mirror test shows very low water permeation rates of 2 × 10-3 g m-2 day-1 (23 °C, 45% RH) for a 4.7 µm multilayer, which is equivalent to a 1.9 mm pure Parylene-C coating. According to the packaging standard MIL-STD-883, the helium gas tightness was investigated. These helium permeation measurements predict that a multilayer of 10 µm achieves the hermeticity acceptance criterion required for long-term implantable medical devices.

  5. Mathematical analogies in physics. Thin-layer wave theory

    Directory of Open Access Journals (Sweden)

    José M. Carcione

    2014-03-01

    Full Text Available Field theory applies to elastodynamics, electromagnetism, quantum mechanics, gravitation and other similar fields of physics, where the basic equations describing the phenomenon are based on constitutive relations and balance equations. For instance, in elastodynamics, these are the stress-strain relations and the equations of momentum conservation (Euler-Newton law. In these cases, the same mathematical theory can be used, by establishing appropriate mathematical equivalences (or analogies between material properties and field variables. For instance, the wave equation and the related mathematical developments can be used to describe anelastic and electromagnetic wave propagation, and are extensively used in quantum mechanics. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission problem of a thin layer embedded between dissimilar media, considering the presence of anisotropy and attenuation/viscosity in the viscoelastic case, conductivity in the electromagnetic case and a potential barrier in quantum physics (the tunnel effect. The analogy is mainly illustrated with geophysical examples of propagation of S (shear, P (compressional, TM (transverse-magnetic and TE (transverse-electric waves. The tunnel effect is obtained as a special case of viscoelastic waves at normal incidence.

  6. Junction conditions in quadratic gravity: thin shells and double layers

    Science.gov (United States)

    Reina, Borja; Senovilla, José M. M.; Vera, Raül

    2016-05-01

    The junction conditions for the most general gravitational theory with a Lagrangian containing terms quadratic in the curvature are derived. We include the cases with a possible concentration of matter on the joining hypersurface—termed as thin shells, domain walls or braneworlds in the literature—as well as the proper matching conditions where only finite jumps of the energy-momentum tensor are allowed. In the latter case we prove that the matching conditions are more demanding than in general relativity. In the former case, we show that generically the shells/domain walls are of a new kind because they possess, in addition to the standard energy-momentum tensor, a double layer energy-momentum contribution which actually induces an external energy flux vector and an external scalar pressure/tension on the shell. We prove that all these contributions are necessary to make the entire energy-momentum tensor divergence-free, and we present the field equations satisfied by these energy-momentum quantities. The consequences of all these results are briefly analyzed.

  7. Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Nurhandoko, Bagus Endar B., E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com [Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Basic Science Center A 4" t" hfloor, Physics Dept., FMIPA, Institut Teknologi Bandung (Indonesia); Rock Fluid Imaging Lab., Bandung (Indonesia); Susilowati, E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com [Rock Fluid Imaging Lab., Bandung (Indonesia)

    2015-04-16

    Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied about the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia.

  8. Fibromyalgia Is Correlated with Retinal Nerve Fiber Layer Thinning

    Science.gov (United States)

    Garcia-Martin, Elena; Garcia-Campayo, Javier; Puebla-Guedea, Marta; Ascaso, Francisco J.; Roca, Miguel; Gutierrez-Ruiz, Fernando; Vilades, Elisa; Polo, Vicente; Larrosa, Jose M.; Pablo, Luis E.; Satue, Maria

    2016-01-01

    Objective To investigate whether fibromyalgia induces axonal damage in the optic nerve that can be detected using optical coherence tomography (OCT), as the retinal nerve fiber layer (RNFL) is atrophied in patients with fibromyalgia compared with controls. Methods Fibromyalgia patients (n = 116) and age-matched healthy controls (n = 144) were included in this observational and prospective cohort study. All subjects underwent visual acuity measurement and structural analysis of the RNFL using two OCT devices (Cirrus and Spectralis). Fibromyalgia patients were evaluated according to Giesecke’s fibromyalgia subgroups, the Fibromyalgia Impact Questionnaire (FIQ), and the European Quality of Life-5 Dimensions (EQ5D) scale. We compared the differences between fibromyalgia patients and controls, and analyzed the correlations between OCT measurements, disease duration, fibromyalgia subgroups, severity, and quality of life. The impact on quality of life in fibromyalgia subgroups and in patients with different disease severity was also analyzed. Results A significant decrease in the RNFL was detected in fibromyalgia patients compared with controls using the two OCT devices: Cirrus OCT ganglion cell layer analysis registered a significant decrease in the minimum thickness of the inner plexiform layer (74.99±16.63 vs 79.36±3.38 μm, respectively; p = 0.023), nasal inferior, temporal inferior and temporal superior sectors (p = 0.040; 0.011 and 0.046 respectively). The Glaucoma application of the Spectralis OCT revealed thinning in the nasal, temporal inferior and temporal superior sectors (p = 0.009, 0.006, and 0.002 respectively) of fibromyalgia patients and the Axonal application in all sectors, except the nasal superior and temporal sectors. The odds ratio (OR) to estimate the size effect of FM in RNFL thickness was 1.39. RNFL atrophy was detected in patients with FIQ scores damage in the RNFL that can be detected using innocuous and non-invasive OCT, even in the early

  9. Two-dimensional thin-layer chromatographic method for the analysis of ochratoxin A in green coffee.

    Science.gov (United States)

    Ventura, Meritxell; Anaya, Ivan; Broto-Puig, Francesc; Agut, Montserrat; Comellas, Lluís

    2005-09-01

    A low-cost thin-layer chromatographic method has been developed for the presumptive measurement of ochratoxin A (OTA) at 5 microg/kg in green coffee beans. The analytical method consisted of extracting OTA by shaking the beans with a mixture of methanol and aqueous sodium bicarbonate solution, which was then purified by liquid-liquid partition into toluene. OTA was separated by normal-phase two-dimensional thin-layer chromatography and detected by visual estimation of fluorescence intensity under a UV lamp at 365 nm. The chromatography solvents were toluene-methanol-formic acid (8:2:0.03) for the first development and petroleum ether-ethyl acetate-formic acid (8:10:1) for the second dimension development. This method was tested with uncontaminated green coffee bean samples spiked with an OTA standard at four different concentrations (5, 10, 20, and 30 microg/kg). The method is rapid, simple, and very easy to implement in coffee-producing countries. It is highly selective and does not involve the use of chlorinated solvents in the sample extraction step. This inexpensive method has been applied to different types of green coffee samples from various countries (Zimbabwe, Brazil, India, Uganda, Colombia, and Indonesia) and different manufacturers, and no OTA below the detection limit of 5 microg/kg was detected in any samples analyzed. PMID:16161695

  10. Fibromyalgia Is Correlated with Retinal Nerve Fiber Layer Thinning

    Science.gov (United States)

    Garcia-Martin, Elena; Garcia-Campayo, Javier; Puebla-Guedea, Marta; Ascaso, Francisco J.; Roca, Miguel; Gutierrez-Ruiz, Fernando; Vilades, Elisa; Polo, Vicente; Larrosa, Jose M.; Pablo, Luis E.; Satue, Maria

    2016-01-01

    Objective To investigate whether fibromyalgia induces axonal damage in the optic nerve that can be detected using optical coherence tomography (OCT), as the retinal nerve fiber layer (RNFL) is atrophied in patients with fibromyalgia compared with controls. Methods Fibromyalgia patients (n = 116) and age-matched healthy controls (n = 144) were included in this observational and prospective cohort study. All subjects underwent visual acuity measurement and structural analysis of the RNFL using two OCT devices (Cirrus and Spectralis). Fibromyalgia patients were evaluated according to Giesecke’s fibromyalgia subgroups, the Fibromyalgia Impact Questionnaire (FIQ), and the European Quality of Life-5 Dimensions (EQ5D) scale. We compared the differences between fibromyalgia patients and controls, and analyzed the correlations between OCT measurements, disease duration, fibromyalgia subgroups, severity, and quality of life. The impact on quality of life in fibromyalgia subgroups and in patients with different disease severity was also analyzed. Results A significant decrease in the RNFL was detected in fibromyalgia patients compared with controls using the two OCT devices: Cirrus OCT ganglion cell layer analysis registered a significant decrease in the minimum thickness of the inner plexiform layer (74.99±16.63 vs 79.36±3.38 μm, respectively; p = 0.023), nasal inferior, temporal inferior and temporal superior sectors (p = 0.040; 0.011 and 0.046 respectively). The Glaucoma application of the Spectralis OCT revealed thinning in the nasal, temporal inferior and temporal superior sectors (p = 0.009, 0.006, and 0.002 respectively) of fibromyalgia patients and the Axonal application in all sectors, except the nasal superior and temporal sectors. The odds ratio (OR) to estimate the size effect of FM in RNFL thickness was 1.39. RNFL atrophy was detected in patients with FIQ scores fibromyalgia (FIQ≥60) compared with patients with mild fibromyalgia (FIQfibromyalgia exhibited

  11. Multifunctional carbon nanotube thin film composites by layer-by-layer assembly technique

    Science.gov (United States)

    Shim, Bong Sup

    Polymeric layer-by-layer (LBL) assembly offers a pathway for multifunctional/multicomponent materials with molecular-scale control of stratified structures. Among the wide variety nanoscale building blocks such as nanowires and nanodots, single-walled carbon nanotubes (SWNTs) are regarded as one of the most versatile because of their superior mechanical and electrical properties as well as geometrical perfection. In this thesis, LBL assembled SWNT thin film nanocomposites with high mechanical strength/toughness and with high electrical/optical properties are presented. Exceptional exfoliation state of SWNTs and controlled nm-thick layered structures are the basis for achieving tunable physical properties. Highly anisotropic features of SWNTs are translated into 2 dimensional alignments by meniscus combing technique during LBL assemblies. Advanced LBL assemblies by dewetting methods are also introduced, which significantly accelerate the process with improved lateral organization of nanowires. Furthermore, SWNT composite coating on commodity cotton yarns produced intelligent electronic textiles (e-textiles) with intrinsic humidity sensibility. This e-textile has been further combined with antigen/antibody sensing capability in order to develop a selective albumin biosensor which provides a direct route for the application of these materials as wearable biomonitoring and telemedicine sensors.

  12. Identificação de alcalóides xantínicos do guaraná (Paullinia cupana KBK por cromatografia em camada delgada em amostras de urina Identification of xanthine alkaloids of guaraná in urine samples using thin-layer chromatography

    Directory of Open Access Journals (Sweden)

    Maurílio de Carvalho Mousinho

    1986-01-01

    Full Text Available É proposto um esquema analítico, simples e sensível, para identificação de bases xânticas do guaraná em material biológico. Amostras de urina de consumidores de guaraná são submetidos à extração com clorofórmio em meio alcalino. Após evaporação dos extratos, os resíduos são transferidos para uma cromatoplaca de silicagel G (0,25 mm e desenvolvidos em acetato de etilaciclohexano-metanol-hidróxido de amônio, 70:15:10:5 (11,5 cm e, a seguir, acetato de etilaciclohexano-hidróxido de amônio, 50:40:0,1 (15,5 cm na mesma direção. A revelação é feita com o reativo de DRAGENDORFF iodado.A simple and sensitive thin layer chromatographic analytical method is proposed for the identification of xanthic bases of guarana Paullinia cupana HBK in urine samples. The samples were obtained from the consumers of the stimulant drink and submitted to extraction with chloroform in alkaline medium. After evaporation of the extracts residues were transferred to silicagel G (0,25 mm thin-layer plates and developed with ethylacetatecyclohexane-methanol, ammonium hydroxide 50:40:0,1 for 14,5 cm in the same dimension. The spots were revealed with Dragendorff-iodate chromogen agent.

  13. The effect of Cr buffer layer thickness on voltage generation of thin-film thermoelectric modules

    International Nuclear Information System (INIS)

    The effect of Cr buffer layer thickness on the open-circuit voltage generated by thin-film thermoelectric modules of Bi0.5Sb1.5Te3 (p-type) and Bi2Te2.7Se0.3 (n-type) materials was investigated. A Cr buffer layer, whose thickness generally needs to be optimized to improve adhesion depending on the substrate surface condition, such as roughness, was deposited between thermoelectric thin films and glass substrates. When the Cr buffer layer was 1 nm thick, the Seebeck coefficients and electrical conductivity of 1 µm thermoelectric thin films with the buffer layers were approximately equal to those of the thermoelectric films without the buffer layers. When the thickness of the Cr buffer layer was 1 µm, the same as the thermoelectric films, the Seebeck coefficients of the bilayer films were reduced by an electrical current flowing inside the Cr buffer layer and the generation of Cr2Te3. The open-circuit voltage of the thin-film thermoelectric modules decreased with an increase in the thickness of the Cr buffer layer, which was primarily induced by the electrical current flow. The reduction caused by the Cr2Te3 generation was less than 10% of the total voltage generation of the modules without the Cr buffer layers. The voltage generation of thin-film thermoelectric modules could be controlled by the Cr buffer layer thickness. (paper)

  14. Photoluminescence-based quality control for thin film absorber layers of photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Repins, Ingrid L.; Kuciauskas, Darius

    2015-07-07

    A time-resolved photoluminescence-based system providing quality control during manufacture of thin film absorber layers for photovoltaic devices. The system includes a laser generating excitation beams and an optical fiber with an end used both for directing each excitation beam onto a thin film absorber layer and for collecting photoluminescence from the absorber layer. The system includes a processor determining a quality control parameter such as minority carrier lifetime of the thin film absorber layer based on the collected photoluminescence. In some implementations, the laser is a low power, pulsed diode laser having photon energy at least great enough to excite electron hole pairs in the thin film absorber layer. The scattered light may be filterable from the collected photoluminescence, and the system may include a dichroic beam splitter and a filter that transmit the photoluminescence and remove scattered laser light prior to delivery to a photodetector and a digital oscilloscope.

  15. Layer thinning transition in an achiral four-ring hockey stick shaped liquid crystal

    Science.gov (United States)

    Paul, Manoj Kr.; Nath, Rahul K.; Moths, Brian; Pan, LiDong; Wang, Shun; Deb, Rajdeep; Shen, Yongqiang; Rao, Nandiraju V. S.; Huang, C. C.

    2012-12-01

    Depolarized reflected light microscopy and high resolution optical reflectivity measurements have been conducted on free-standing films of an achiral four-ring hockey stick shaped liquid crystal exhibiting SmA-B2-SmX* transition sequence. A layer thinning transition above the bulk isotropic-SmA phase transition has been observed. This behaviour was highly irreproducible, indicating an irregular layer thinning transition. From optical reflectivity data, both thickness of the free-standing films and the smectic interlayer spacing were determined. This is the first report of the layer thinning transition in a hockey stick shaped liquid crystal.

  16. nvestigation on influencing factors in determination of hydrocarbons in heavy oils by thin-layer chromatography flame/ionization detector.%棒状薄层色谱/氢火焰离子化检测器法测定重油烃族组成影响因素的探讨

    Institute of Scientific and Technical Information of China (English)

    杨海鹰; 顾洁; 蔺玉贵

    2001-01-01

    The influencing factors in the determination of hydrocarbons (saturates, aromatics, resins) in heavy oils by thin layer chromatography/flame ionization detection (TLC/FID) were investigated. It has been found that the solvent co -volatization may cause sample loss during the spotting and developing process, and that the quantitative calibration factors can not be used universally. Because the flame temperature of TLC/FLD is much lower than that of GC/FID, the transformation of different compounds in the flame of FID is varied.%对应用棒状薄层色谱/氢火焰离子化检测器(TLC/FID)测定重油烃族组成(饱和烃、芳烃、胶质)时的影响因素作了探讨。研究发现,在点样及展开过程中,溶剂共挥发可引起样品损失;而且,由于TLC/FID的火焰温度远低于一般GC条件下FID的火焰温度,使不同化合物在FID上的燃烧转化情况有差异,因而其定量校正因子不具有通用性。

  17. Back contact buffer layer for thin-film solar cells

    Science.gov (United States)

    Compaan, Alvin D.; Plotnikov, Victor V.

    2014-09-09

    A photovoltaic cell structure is disclosed that includes a buffer/passivation layer at a CdTe/Back contact interface. The buffer/passivation layer is formed from the same material that forms the n-type semiconductor active layer. In one embodiment, the buffer layer and the n-type semiconductor active layer are formed from cadmium sulfide (CdS). A method of forming a photovoltaic cell includes the step of forming the semiconductor active layers and the buffer/passivation layer within the same deposition chamber and using the same material source.

  18. Thin layer chromatographic analysis of food colorants from three morphotypes of annatto (Bixa orellana L.

    Directory of Open Access Journals (Sweden)

    Hari Pada Seal

    2012-06-01

    Full Text Available This article describes a simple solvent extraction method for the extraction of colorants from the three morphotypes such as, (Morphotype-1 (M1, Morphotype-2 (M2, and Morphotype-3 (M3 of Annatto (Bixa orellana L. seeds, and their separation, vivid, and qualitative demonstration by thin-layer chromatography. Several solvent systems (hexane, chloroform, acetone, ethanol, and a mixed-solvent having composition of CHCl3/C2H5OH/CH3COOH (80:2:1 were applied for extraction of colored components. It was observed that a large portion of colorants was extracted by chloroform. Its effluent was deep brick red in color and transparent. Furthermore, various carrier solvent systems (Benzene-Ethyl acetate were used to separate the components from the extracts. Carrier solvent system with the ratio of 7:3 was found as superior solvent for chloroform extracts. Three colored-spots were observed for all morphotypes. Among them, the first one was yellow colored having very low polarity and the second and third spots were both redbrick colored having medium and higher polarity respectively. In addition, for M1 no colorless-spot was observed in low and medium polar systems, revealing that the amount of wax and gum were minimum in the extract and superior morphotype among the three.

  19. Thin layers and species-specific characterization of the phytoplankton community in Monterey Bay, California, USA

    Science.gov (United States)

    Rines, J. E. B.; McFarland, M. N.; Donaghay, P. L.; Sullivan, J. M.

    2010-01-01

    During the summers of 2005 and 2006, experiments designed to understand the properties of densely concentrated, thin layers of plankton and the processes governing their dynamics were conducted in Monterey Bay, California, USA. Our goal was to elucidate the role that species-specific properties of phytoplankton play in thin layer dynamics. Using adaptive sampling, we collected water samples from inside and outside bio-optical features of the water column. Characterization of the phytoplankton was compiled from live and preserved samples, and analyzed within a framework of physical, optical, chemical and acoustical data. In both years, Monterey Bay was home to an extraordinarily diverse assemblage of phytoplankton and other protists. Bioluminescent dinoflagellates, and Harmful Algal Bloom (HAB) taxa were common. In 2005, community assemblages were widespread, thus advection of water through the experimental mooring array did not result in floristic changes. In 2006 phytoplankton were very patchy in horizontal distribution, and advection of water through the array was at times accompanied by dramatic shifts in community composition. Individual taxa often exhibited disparate patterns of vertical distribution, with some found throughout the water column, whereas others were restricted to narrow depth intervals. Thin layers were observed in both years. In 2005, the dinoflagellate Akashiwo sanguinea formed intense thin layers near the pycnocline at night, and migrated to near surface waters at dawn. In 2006, layer composition was more complex, and related to the water mass present at the time of sampling. Optically detected thin layers of phytoplankton can be studied from the perspective of the impact their high biomass has on both ecological processes, and ocean optics. But thin layers can also be studied from the species-specific perspective of each organism, its role within the thin layer habitat, and the impact that life within a thin layer has on its life history

  20. Review: Applications of chromatography in forensic sciences

    Directory of Open Access Journals (Sweden)

    Manoj S. Charde

    2014-04-01

    Full Text Available This article reviews the use of different Chromatography techniques in the forensic science, Chromatographic technique is very sensitive and selective. Different types of chromatography techniques used were Liquid chromatography -mass spectrometry, Gas chromatography–mass spectrometry, Thin layer chromatography, HPTLC in investigating criminal cases of which chemical warfare’s, terrorist attacks, smugglers, drug abuse, alcoholics. This techniques are promising to detect even pictogram or very less, with selectivity and sensitivity.

  1. The Role Seemingly of Amorphous Silica Gel Layers in Chiral Separations by Planar Chromatography

    Directory of Open Access Journals (Sweden)

    Teresa Kowalska

    2007-12-01

    Full Text Available In planar chromatography, silica gel appears as the most frequently used adsorbent. Its preference as planar chromatographic stationary phase is due to its high specific surface area (ca. 700 m2 g-1 and relatively simple active sites (silanol groups, Si-OH. The high specific surface area of silica gel and a high density of coverage of its surface with the silanol active sites contribute jointly to an excellent separation performance of this adsorbent. In our experiments on chiral separation of the enantiomer pairs by planar chromatography, contradictory behavior of the silica gel layers versus the chiral compounds was observed. The migration tracks of chiral compounds in the ascending planar chromatographic mode were not vertical but bent on either side being a function of analyte chirality. This deviation of the analyte’s migration track was noticed, when using the densitometric scanner to quantify the respective chromatograms. In order to confirm the hypothesis as to the microcrystalline nature of silica gel used in liquid chromatography, it was further investigated through circular dichroism (CD and the data thereof confirmed that the ‘chromatographic’ silica gels are not amorphous but microcrystalline, contributing to the (partial horizontal enantioseparation of the antimer pairs. This paper summarizes the results of our investigation on the microcrystalline nature of silica gels used in planar chromatography and their impact on enantioseparation of the selected pairs of antimers.

  2. Growth of α-sexithiophene nanostructures on C60 thin film layers

    DEFF Research Database (Denmark)

    Radziwon, Michal Jędrzej; Madsen, Morten; Balzer, Frank;

    2014-01-01

    Organic molecular beam grown -sexithiophene (-6T) forms nanostructured thin films on buckminsterfullerene (C60) thin film layers. At substrate temperatures of 300K during growth a rough continuous film is observed, which develop to larger elongated islands and dendritic- as well as needle like...

  3. Optimization of optical absorption in thin layers of amorphous silicon enhanced by silver nanospheres

    CERN Document Server

    Omelyanovich, Mikhail; Simovski, Constantin

    2015-01-01

    We study a highly controllable perfect plasmonic absorber -- a thin metamaterial layer which possess balanced electric and magnetic responses in some frequency range. We show that this regime is compatible with both metal-backed variant of the structure or its semitransparent variant. This regime can be implemented in a prospective thin-film photovoltaic cell with negligible parasitic losses.

  4. Atomic layer deposition of ZnO thin films and dot structures

    International Nuclear Information System (INIS)

    Successful growth of thin films and quantum dots of ZnO by atomic layer deposition (ALD) is reported. Properties of ZnO films produced by four different ALD-procedures and by oxidation of ALD-grown ZnS films are discussed. The use of thin ZnO films as buffer layers for GaN deposition is also shortly described. (author)

  5. Memory effect and redistribution of cavitation nuclei in a thin liquid layer.

    Science.gov (United States)

    Bai, Lixin; Lin, Weijun; Wu, Pengfei; Deng, Jingjun; Li, Chao; Xu, Delong; Wang, Dong; Chen, Lishuo

    2016-09-01

    Temporal evolution and spatial distribution of acoustic cavitation structures in a thin liquid layer were investigated experimentally with high-speed photography. The inception and disappearance processes of cavitation bubble cloud revealed that the metastable cavitaton structures formed in the thin liquid layer caused a long-term "memory effect". A factor which weakens the memory effect was identified. The distribution of cavitation nuclei was investigated by changing the temporal decay of the memory effect. PMID:27150763

  6. Ballistic phonon transport in ultra-thin silicon layers: Effects of confinement and orientation

    OpenAIRE

    Karamitaheri, Hossein; Neophytou, Neophytos; Kosina, Hans

    2013-01-01

    We investigate the effect of confinement and orientation on the phonon transport properties of ultra-thin silicon layers of thicknesses between 1 nm-16 nm. We employ the modified valence force field method to model the lattice dynamics and the ballistic Landauer transport formalism to calculate the thermal conductance. We consider the major thin layer surface orientations {100}, {110}, {111}, and {112}. For every surface orientation, we study thermal conductance as a function of the transport...

  7. Optical and Electrical Characteristic of Layer-by-layer Sol-gel Spin Coated Nanoparticles ZnO Thin Films

    International Nuclear Information System (INIS)

    Transparent ZnO thin films have been deposited on glass substrate using sol-gel spin coating technique. 0.35 M sol were prepared by dissolving zinc acetate dehydrate in 2-methoxyethanol with monoethanolamine as the stabilizer. In this paper, a novel method called layer-by-layer is introduced, where the thin film is not only dried after each layer is spin-coated, but also directly annealed at 500 degree Celsius to improve the crystallinity of the films. Samples without annealing were also prepared as the control sample. ZnO thin films were characterized using field emission scanning electron microscopy, X-ray diffraction, current-voltage measurement, UV-Vis spectroscopy and photoluminescence spectroscopy. The results revealed that layer by- layer ZnO thin films have better conductivity and higher intensity peak for PL spectra at visible spectra of 580 nm. FE-SEM images shows nanoparticles almost hexagonal shaped with high crystallinity compared to control samples. (author)

  8. Crystallinity Improvement of ZnO Thin Film on Different Buffer Layers Grown by MBE

    Directory of Open Access Journals (Sweden)

    Shao-Ying Ting

    2012-01-01

    Full Text Available The material and optical properties of ZnO thin film samples grown on different buffer layers on sapphire substrates through a two-step temperature variation growth by molecular beam epitaxy were investigated. The thin buffer layer between the ZnO layer and the sapphire substrate decreased the lattice mismatch to achieve higher quality ZnO thin film growth. A GaN buffer layer slightly increased the quality of the ZnO thin film, but the threading dislocations still stretched along the c-axis of the GaN layer. The use of MgO as the buffer layer decreased the surface roughness of the ZnO thin film by 58.8% due to the suppression of surface cracks through strain transfer of the sample. From deep level emission and rocking curve measurements it was found that the threading dislocations play a more important role than oxygen vacancies for high-quality ZnO thin film growth.

  9. Crystalline-crystalline phase transformation in two-dimensional In2Se3 thin layers.

    Science.gov (United States)

    Tao, Xin; Gu, Yi

    2013-08-14

    We report, for the first time, the fabrication of single-crystal In2Se3 thin layers using mechanical exfoliation and studies of crystalline-crystalline (α → β) phase transformations as well as the corresponding changes of the electrical properties in these thin layers. Particularly, using electron microscopy and correlative in situ micro-Raman and electrical measurements, we show that, in contrast to bulk single crystals, the β phase can persist in single-crystal thin layers at room temperature (RT). The single-crystal nature of the layers before and after the phase transition allows for unambiguous determination of changes in the electrical resistivity. Specifically, the β phase has an electrical resistivity about 1-2 orders of magnitude lower than the α phase. Furthermore, we find that the temperature of the α → β phase transformation increases by as much as 130 K with the layer thickness decreasing from ~87 nm to ~4 nm. These single-crystal thin layers are ideal for studying the scaling behavior of the phase transformations and associated changes of the electrical properties. For these In2Se3 thin layers, the accessibility of the β phase at RT, with distinct electrical properties than the α phase, provides the basis for multilevel phase-change memories in a single material system.

  10. Cross-Field Current Instabilities in Thin Ionization Layers and the Enhanced Aurora

    Energy Technology Data Exchange (ETDEWEB)

    Jay R. Johnson and Hideo Okuda

    2008-05-20

    Nearly half of the time, auroral displays exhibit thin, bright layers known as \\enhanced aurora." There is a substantial body of evidence that connects these displays with thin, dense, heavy ion layers in the E-region. Based on the spectral characteristics of the enhanced layers, it is believed that they result when wave-particle interaction heats ambient electrons to energies at or just above the 17 eV ionization energy of N2. While there are several possible instabilities that could produce suprathermal electrons in thin layers, there has been no clear theoretical investigation which examines in detail how wave instabilities in the thin ionization layers could develop and produce the suprathermal electrons. We examine instabilities which would occur in thin, dense, heavy ion layers using extensive analytical analysis combined with particle simulations. We analyze a cross field current instability that is found to be strongly unstable in the heavy ion layers. Electrostatic simulations show that substantial heating of the ambient electrons occurs with energization at or above the N2 ionization energy.

  11. Studies of oxide-based thin-layered heterostructures by X-ray scattering methods

    Energy Technology Data Exchange (ETDEWEB)

    Durand, O. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France)]. E-mail: olivier.durand@thalesgroup.com; Rogers, D. [Nanovation SARL, 103 bis rue de Versailles 91400 Orsay (France); Universite de Technologie de Troyes, 10-12 rue Marie Curie, 10010 (France); Teherani, F. Hosseini [Nanovation SARL, 103 bis rue de Versailles 91400 Orsay (France); Andrieux, M. [LEMHE, ICMMOCNRS-UMR 8182, Universite d' Orsay, Batiment 410, 91410 Orsay (France); Modreanu, M. [Tyndall National Institute, Lee Maltings, Prospect Row, Cork (Ireland)

    2007-06-04

    Some X-ray scattering methods (X-ray reflectometry and Diffractometry) dedicated to the study of thin-layered heterostructures are presented with a particular focus, for practical purposes, on the description of fast, accurate and robust techniques. The use of X-ray scattering metrology as a routinely working non-destructive testing method, particularly by using procedures simplifying the data-evaluation, is emphasized. The model-independent Fourier-inversion method applied to a reflectivity curve allows a fast determination of the individual layer thicknesses. We demonstrate the capability of this method by reporting X-ray reflectometry study on multilayered oxide structures, even when the number of the layers constitutive of the stack is not known a-priori. Fast Fourier transform-based procedure has also been employed successfully on high resolution X-ray diffraction profiles. A study of the reliability of the integral-breadth methods in diffraction line-broadening analysis applied to thin layers, in order to determine coherent domain sizes, is also reported. Examples from studies of oxides-based thin-layers heterostructures will illustrate these methods. In particular, X-ray scattering studies performed on high-k HfO{sub 2} and SrZrO{sub 3} thin-layers, a (GaAs/AlOx) waveguide, and a ZnO thin-layer are reported.

  12. Cross-Field Current Instabilities in Thin Ionization Layers and the Enhanced Aurora

    International Nuclear Information System (INIS)

    Nearly half of the time, auroral displays exhibit thin, bright layers known as 'enhanced aurora'. There is a substantial body of evidence that connects these displays with thin, dense, heavy ion layers in the E-region. Based on the spectral characteristics of the enhanced layers, it is believed that they result when wave-particle interaction heats ambient electrons to energies at or just above the 17 eV ionization energy of N2. While there are several possible instabilities that could produce suprathermal electrons in thin layers, there has been no clear theoretical investigation which examines in detail how wave instabilities in the thin ionization layers could develop and produce the suprathermal electrons. We examine instabilities which would occur in thin, dense, heavy ion layers using extensive analytical analysis combined with particle simulations. We analyze a cross field current instability that is found to be strongly unstable in the heavy ion layers. Electrostatic simulations show that substantial heating of the ambient electrons occurs with energization at or above the N2 ionization energy.

  13. Electrical resistivity of assembled transparent inorganic oxide nanoparticle thin layers: Influence of silica, insulating impurities and surfactant layer thickness

    OpenAIRE

    Bubenhofer, Stephanie B.; Schumacher, Christoph M; Koehler, Fabian M.; Luechinger, Norman A.; SOTIRIOU, GEORGIOS A.; Grass, Robert N.; Stark, Wendelin J

    2012-01-01

    Transparent, conductive layers prepared from nanoparticle dispersion of doped oxides are highly sensitive to impurities. Currently investigated cost efficient and fast production of thin conducting films for use in consumer electronics relies on wet processing such as spin and/or dip coating of surfactant-stabilized nanoparticle dispersions. This inherently results in entrainment of organic and inorganic impurities into the conducting layer leading to largely varying electrical conductivity. ...

  14. The thin-layer effect and interfacial stability in a two-layer Couette flow with similar liquids

    OpenAIRE

    Renardy, Y

    1987-01-01

    The linear stability of Couette flow composed of two layers of immiscible fluids, one lying on top of the other, is considered for the special case when the two fluids have similar mechanical properties. The interfacial eigenvalue is found in closed form by considering the two‐fluid problem as a perturbation of the one‐fluid problem. The importance of the role played by the viscosity difference, when one of the fluids is in a thin layer, is illustrated.

  15. Preparation and characterization of polymeric thin films containing gold nanoshells via electrostatic layer-by-layer self-assembly

    International Nuclear Information System (INIS)

    As an initial step in the development of surfaces for collecting thermal energy, gold shell/silica core particles (∼ 200 nm in diameter with shells ∼ 25 nm thick) were synthesized and incorporated into organic polymeric thin films. The morphologies of these nanoshells were characterized with scanning and transmission electron microscopy. Powder X-ray diffraction demonstrated that the gold layers were highly crystalline. Thin films containing the gold nanoshells and polyethyleneimine were generated using dip-coating techniques based on electrostatic layer-by-layer self-assembly methods. Scanning electron microscopy was used to image the resultant composite films, which contained uniformly distributed gold nanoshells with limited aggregation. The optical properties were analyzed by absorption spectroscopy, revealing broad extinctions ranging from the visible to the near-IR spectral regions. X-ray photoelectron spectroscopy spectra were also obtained to determine the elements present and the oxidation states of these elements. - Highlights: • Prepared gold nanoshells with broad light absorption from visible to near IR. • Added the gold nanoshells to polyethyleneimine films via layer-by-layer assembly. • The resulting layered thin films exhibited minimal gold nanoshell aggregation

  16. Thin TaC layer produced by ion mixing

    DEFF Research Database (Denmark)

    Barna, Árpád; Kotis, László; Pécz, Béla;

    2012-01-01

    Ion-beam mixing in C/Ta layered systems was investigated. C 8nm/Ta 12nm and C 20nm/Ta 19nm/C 20nm layer systems were irradiated by Ga+ ions of energy in the range of 2–30keV. In case of the 8nm and 20nm thick C cover layers applying 5–8keV and 20–30keV Ga+ ion energy, respectively resulted...... in strongly asymmetric ion mixing; the carbon was readily transported to the Ta layer, while the reverse process was much weaker. Because of the asymmetrical transport the C/TaC interface remained sharp independently from the applied fluence. The carbon transported to the Ta layer formed Ta......Cx. The stoichiometry of the carbide produced varied along the depth. The TaCx layer contained implanted Ga, the concentration of which decreased with increasing depth. The thickness of the TaCx layer could be tailored by the ion fluence and energy making possible to produce coating layer of desired thickness....

  17. Low-temperature nitriding of iron through a thin nickel layer

    NARCIS (Netherlands)

    Inia, D.K.; Propper, M.H.; Arnoldbik, W.M.; Vredenberg, A.M.; Boerma, D.O

    1997-01-01

    We present a new method for nitriding iron at low temperatures. First, iron is coated with a thin layer of nickel (similar to 36 nm), after which it is exposed to an NH3 atmosphere at temperatures below 300 degrees C. Underneath the nickel layer epsilon-Fe3-xN is formed at temperatures as low as 225

  18. TWO-LAYER MODEL DESCRIPTION OF POLYMER THIN FILM DYNAMICS

    Institute of Scientific and Technical Information of China (English)

    Dong-dong Peng; Ran-xing Nancy Li; Chi-hang Lam; Ophelia K.C.Tsui

    2013-01-01

    Experiments in the past two decades have shown that the glass transition temperature of polymer films can become noticeably different from that of the bulk when the film thickness is decreased below ca.100 nm.It is broadly believed that these observations are caused by a nanometer interfacial layer with dynamics faster or slower than that of the bulk.In this paper,we examine how this idea may be realized by using a two-layer model assuming a hydrodynamic coupling between the interfacial layer and the remaining,bulk-like layer in the film.Illustrative examples will be given showing how the two-layer model is applied to the viscosity measurements of polystyrene and polymethylmethacrylate films supported by silicon oxide,where divergent thickness dependences are observed.

  19. Thin tungsten telluride layer preparation by thermal annealing

    Science.gov (United States)

    Lu, Wei; Zhang, Yudao; Zhu, Zusong; Lai, Jiawei; Zhao, Chuan; Liu, Xuefeng; Liu, Jing; Sun, Dong

    2016-10-01

    We report a simple method to prepare a thin Tungsten Telluride (WTe2) flake with accurate thickness control, which allows preparing and studying this two dimensional material conveniently. First, the WTe2 flake, which is relatively thick due to its strong interlayer van der Waals forces, is obtained by a conventional mechanical exfoliation method. Then, the exfoliated flake is annealed at 600 °C under a constant Ar protecting flow. Raman and atomic force spectroscopy characterizations demonstrate that thermal annealing can effectively thin down the WTe2 flake and retain its original lattice structure, though its surface smoothness is slightly deteriorated. Additionally, systematical study indicates that the thinning process strongly depends on the initial thickness of the WTe2 flake before annealing: the thinning rate increases from 0.12 nm min-1 to 0.36 nm min-1 as the initial thickness increases from 10 nm to 45 nm, while the roughness of the final product also increases with the increase of its initial thickness. However, the method fails when it is applied to WTe2 flakes thicker than 100 nm, resulting in uneven or burnt surface, which is possibly caused by big cavities formed by a large amount of defects gathered at the top surface.

  20. Electrospun nanofiber layers with incorporated photoluminescence indicator for chromatography and detection of ultraviolet-active compounds.

    Science.gov (United States)

    Kampalanonwat, Pimolpun; Supaphol, Pitt; Morlock, Gertrud E

    2013-07-19

    For the first time, electrospun nanofiber phases were fabricated with manganese-activated zinc silicate as photoluminescent indicator (UV254) to transfer and enlarge its application to the field of UV-active compounds. By integration of such an indicator, UV-active compounds got visible on the chromatogram. The separation of 7 preservatives and a beverage sample were studied on the novel luminescent polyacrylonitrile layers. The mat thickness and mean fiber diameters were calculated for additions of different UV254 indicator concentrations. The separation efficiency on the photoluminescent layers was characterized by comparison to HPTLC layers and calculation of the plate numbers and resolutions. Some benefits were the reduction in migration distance (3cm), migration time (12min), analyte (10-nL volumes) and mobile phase volumes (1mL). As ultrathin stationary phase, such layers are suited for their integration into the Office Chromatography concept. For the first time, electrospun nanofiber layers were hyphenated with mass spectrometry and the confirmation of compounds was successfully performed using the elution-head based TLC-MS Interface.

  1. Microstructure and mechanical behavior of a shape memory Ni-Ti bi-layer thin film

    Energy Technology Data Exchange (ETDEWEB)

    Mohri, Maryam [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe (Germany); Nili-Ahmadabadi, Mahmoud, E-mail: nili@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, University of Tehran, Tehran (Iran, Islamic Republic of); Ivanisenko, Julia [Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe (Germany); Schwaiger, Ruth [Karlsruhe Institute of Technology, Institute for Applied Materials, 76021 Karlsruhe (Germany); Hahn, Horst; Chakravadhanula, Venkata Sai Kiran [Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe (Germany)

    2015-05-29

    Two different single-layers and a bi-layer Ni-Ti thin films with chemical compositions of Ni{sub 45}Ti{sub 50}Cu{sub 5}, Ni{sub 50.8}Ti{sub 49.2} and Ni{sub 50.8}Ti{sub 49.2}/Ni{sub 45}Ti{sub 50}Cu{sub 5} (numbers indicate at.%) determined by energy dispersive X-ray spectroscopy were deposited on Si (111) substrates using DC magnetron sputtering. The structures, surface morphology and transformation temperatures of annealed thin films at 500 °C for 15 min and 1 h were studied using grazing incidence X-ray diffraction, transmission electron microscopy (TEM), atomic force microscopy and differential scanning calorimetry (DSC), respectively. Nanoindentation was used to characterize the mechanical properties. The DSC and X-ray diffraction results indicated the austenitic structure of the Ni{sub 50.8}Ti{sub 49.2} and martensitic structure of the Ni{sub 45}Ti{sub 50}Cu{sub 5} thin films while the bi-layer was composed of austenitic and martensitic thin films. TEM study revealed that copper encourages crystallization in the bi-layer such that crystal structure containing nano-precipitates in the Ni{sub 45}Ti{sub 50}Cu{sub 5} layer was detected after 15 min annealing while the Ni{sub 50.8}Ti{sub 49.2} layer crystallized after 60 min at 500 °C. Furthermore, after annealing at 500 °C for 15 min, a precipitate free zone and thin layer amorphous were observed closely to the interface in the top layer. The bi-layer was completely crystallized at 500 °C for 1 h and the orientation of the Ni-rich precipitates indicated a stress gradient in the bi-layer. The bi-layer thin film showed different transformation temperatures and mechanical behavior from the single-layers. The developed bi-layer has different phase transformation temperatures, the higher temperatures of shape memory effect and lower temperature of pseudo-elastic behavior compared to the single-layers. Also, the bi-layer thin film exhibited a combined pseudo-elastic behavior and shape memory effect with a reduced

  2. The reason why thin-film silicon grows layer by layer in plasma-enhanced chemical vapor deposition

    OpenAIRE

    Takuya Kuwahara; Hiroshi Ito; Kentaro Kawaguchi; Yuji Higuchi; Nobuki Ozawa; Momoji Kubo

    2015-01-01

    Thin-film Si grows layer by layer on Si(001)-(2 × 1):H in plasma-enhanced chemical vapor deposition. Here we investigate the reason why this occurs by using quantum chemical molecular dynamics and density functional theory calculations. We propose a dangling bond (DB) diffusion model as an alternative to the SiH3 diffusion model, which is in conflict with first-principles calculation results and does not match the experimental evidence. In our model, DBs diffuse rapidly along an upper layer c...

  3. Fermentation efficiency of cells immobilized on delignified brewers' spent grains after low- and high-temperature thin layer thermal drying.

    Science.gov (United States)

    Tsaousi, Konstantina; Koutinas, Athanasios A; Bekatorou, Argyro; Loukatos, Paul

    2010-09-01

    Low-cost dried yeasts immobilized on delignified brewers' spent grains for use in wine making and brewing were produced by simple thermal drying techniques. To optimize the thermal drying process, vacuum and air stream conditions were examined. Drying of thin layers of the biocatalysts was performed at low (30-38 degrees C) and high temperatures (40-70 degrees C). The fermentation efficiency of the thermally dried biocatalysts was acceptable, with immobilized cells showing a significantly higher thermotolerance compared with free cells. Immobilized cells dried at high temperatures presented slightly improved glucose fermentation efficiency compared with the low-temperature dried biocatalysts. Gas chromatography-mass spectrometry analysis of aroma volatiles of the fermented products revealed an increase of esters, lower higher alcohol formation, and significantly lower concentration of carbonylic compounds.

  4. Mg thin films with Al seed layers for UV plasmonics

    International Nuclear Information System (INIS)

    We demonstrate that the inclusion of aluminum (Al) seed layers allows for the growth of finer grain, smoother magnesium (Mg) films, allowing for improved plasmonic response in the UV spectral range. We deposit Al seed layers and Mg films using DC/RF magnetron sputtering. For Al seed layer thicknesses of 2, 5, 10 and 15 nm, we measure the corresponding optical constants over the wavelength range of 250 to 600 nm using a variable angle spectroscopic ellipsometer and compare the results to a reference 100 nm thick Mg film deposited without a seed layer. The optical constants of Mg depend on the seed layer thicknesses and the surface morphology of Mg films. The surface morphology of the Mg films are characterized using scanning electron microscopy, atomic force microscopy and x-ray diffraction and the surface oxide layer on Mg is examined using x-ray photoelectron spectroscopy. We observe that the presence of the seed layer improves the LSP figure of merit in the UV spectral range of 250–400 nm. From the perspective of plasmonics applications, we find that the best localized surface plasmon resonance (LSP) figures of merit are observed for the 10 nm thick Al seed layer. In fact, the LSP figure of merit of the 100 nm Mg film with and without the Al seed layer is found to be greater than Al films in the spectral range of 250–400 nm, confirming earlier findings with thicker Mg films. (paper)

  5. Validation of thin-layer chromatographic methods for pesticide residue analysis. Results of the coordinated research projects 1996-2002

    International Nuclear Information System (INIS)

    Thin-layer chromatography (TLC) has a long history, but has been used only to a limited extent in pesticide residue analytical laboratories since gas liquid chromatography (GLC) and high performance liquid chromatography (HPLC) became readily available. Recent developments in the quality of plate coating and detection systems, as well as in extraction and cleanup methods have revived interest in TLC. The combination of these procedures with rigid quality control has created a niche for TLC in laboratories working in compliance with ISO 17025 or GLP. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture recognized the importance of testing pesticide residues, especially in countries with limited resources. A coordinated research programme (CRP) was initiated for investigating the application of TLC detection methods to complement the instrumental techniques in pesticide residue analysis. An initial technical contract provided proof of the concept and elaborated the basic procedures, including a substantial database of retention factors and minimum detectable quantities of pesticides. To satisfy the demands from the eligible laboratories, two similar projects were started in 1997 and 1998. The titles of the projects were as follows: (i) Validation of Thin-layer Chromatographic Screening Methods for Pesticide Residue Analysis; and (ii) Alternative Methods to Gas and High Performance Liquid Chromatography for Pesticide Residue Analysis in Grain. Scientists from 18 countries participated in the above noted two projects. The major tasks of this programme were to adapt the methods, check the repeatability and reproducibility of Rf values, the minimum detectable quantities (MDQ) and apply the methods for determining various pesticide residues in representative matrices. Furthermore, they have extended the methods to other pesticides and commodities of interest in their countries and validated the methods elaborated. This TECDOC includes the most

  6. Monolithic growth of partly cured polydimethylsiloxane thin film layers

    DEFF Research Database (Denmark)

    Yu, Liyun; Skov, Anne Ladegaard

    2014-01-01

    The demand for monolithic structures in many applications has increased to enable more reliable and optimized performances such as for dielectric electroactive polymers (DEAPs). For the layers of the elements to grow efficiently together, it is first of all required that the layers adhere together...... to enable interlayer crosslinking reactions either by application of an adhesion promoter or by ensuring that there are reactive, complementary sites available on the two surfaces. Polydimethylsiloxane (PDMS) is a widely used polymer for DEAPs. In this work, two-layered PDMS films are adhered together...... as thermal stabilities of the bilayer elastomer films are observed to change with the curing time of the monolayers before lamination. The objective of this work is to create adhesion of two layers without destroying the original viscoelastic properties of the PDMS films, and hence enable, for example...

  7. Single-borehole measuring method for broken rock zone in gently inclined thin layer weakness structure

    Institute of Scientific and Technical Information of China (English)

    CHEN Qing-fa; ZHOU Ke-ping; LONG Teng-teng; GAO Feng

    2008-01-01

    According to the structural characteristics of gently inclined thin layer rock mass in which lots of weak interlayer existed, the concept of gently inclined thin layer weakness structure was proposed. If single-borehole measuring method of the acoustic along the conventional arrangement mode was used in measuring the broken rock zone in this structure, the change of the relationship curves (Vp-L) between acoustic p-wave velocity (Vp) and borehole depth (L) would present the irregular feature due to the mechanical characteristics of layered rock mass and harmful effects of weak interlayers, and the scope of broken rock zone couldn't be defined quickly. Based on the analysis of the mechanical characteristics of layered rock mass, the propagation rule of acoustic and distributions characteristics of plastic zone and slip zone in layered rock mass, new arrangement mode of acoustic measuring boreholes for broken rock zone in gently inclined thin layer weakness structure was proposed. Namely, the measuring boreholes in two sides were parallel to the strata, the measuring boreholes in the roof and floor perpendicular to the strata. Besides the controlling depth of the measuring boreholes in the scope of the large plastic zones or the large slip zones should be increased. Engineering exampleshowed that new acoustic measuring boreholes arrangement mode had the better applicability and could determine the scope of the broken rock zone in the gently inclined thin layer weakness structure quickly.

  8. Factors determining the structure of Au, Ag and Cr thin layers deposited on alkaline halogen substrates

    International Nuclear Information System (INIS)

    Metal thin layer deposited on dielectric substrates, in general, and on alkaline halogen substrates, in particular, have been thoroughly studied in order to make clear the phenomenology of the formation and development processes, to set out fundamental factors in determining their structure and to determine optimum conditions for the obtaining of monocrystal thin layers or metastable structured thin layers in view of their practical applications. Starting from a systematic programme of experimental investigations, an attempt has been made to investigate the influence of substrate composition, of defects within alkaline halogen substrates and of deposition conditions on the orientated formation and development of Au layer and on the formation of metastable Cr-delta structures in the case of thin Cr layers. A systematic study on the influence of deposition conditions and on alkaline halogen substrates with colloidal centres is carried out in view of elaborating a method for the development of monocrystal Au layers for ''channeling targets''. A correlation between characteristic parameters which define the atomic theory of nucleation including deposition conditions and material parameters, Au parameters for the case of epitaxial layers deposited on KBr, KCl and NaCl substrates has been attempted. (author)

  9. X-Ray Diffractometry of Thin Layers - Possibilities and Problems

    Directory of Open Access Journals (Sweden)

    Vladimir Zucha

    2005-01-01

    Full Text Available Efficieney of two deconvolution methods used in X-ray powder diffraction analysis is compared for thin films of Pd and Pt. The first method is the classical Stokes method and the second one is method of indirect deconvolution. But calculated integral breadth of Gauss and Cauchy components of Voigt function which describe the physical broadening are different. The analysis of the all found pheromones show that the method of indirect deconvolution gives more accurate results.

  10. Numerical study of thin layer ring on improving the ice formation of building thermal storage system

    International Nuclear Information System (INIS)

    Ice thermal storage systems have been widely used in HVAC and R systems for improving energy efficiency and reducing energy costs around the world. In this paper, a numerical model is developed to simulate the ice formation in a typical ice thermal storage system. The first study is to investigate the effect of a cooled cylinder placed in a rectangular space filled with water on the ice formation process. The validated numerical model can predict temperature distribution associated with liquid fraction during the process. Based on the result obtained from the first study, further research is focused on the novel structure of thin layer ring. The computational solutions can demonstrate that the thin layer ring structure can successfully increase an ice generated area and shorten the ice formation period in a typical ice thermal storage system. Finally, a parametric study was carried out to investigate the effect of material, thickness, and arrangement of thin layer ring. It predicted that the heat transfer performance of the thin layer ring is dependent on its material, thickness, and arrangement. Ice formation with novel thin layer ring can be improved by increasing the thermal conductivity of a material. A copper ring has the best performance among aluminum, stainless steel, magnesium alloy. The results show that the ice formation rate can be increased by increasing the thickness of the ring from 0.25 mm to 1 mm, while slowed by increasing from 1 mm to 2 mm and has the best performance with 3 mm ring in this study. Finally, the staggered arrangement of ring shows the best results of the ice formation compared to one parallel and two parallel cases. - Highlights: •A thin layer ring structure is studied systematically to enhance ice formation. •Increasing thermal conductivity of thin layer ring can increase ice formation rate. •Ice formation rate is also dependent on the thickness of thin layer ring. •Increasing thin layer ring area can increase ice

  11. BAlN thin layers for deep UV applications

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin; Voss, Paul L.; Ougazzaden, Abdallah [School of Electrical and Computer Engineering, Georgia Institute of Technology, Metz (France); UMI 2958, Georgia Tech-CNRS, Metz (France); Sundaram, Suresh; El Gmili, Youssef; Moudakir, Tarik [UMI 2958, Georgia Tech-CNRS, Metz (France); Genty, Frederic [Supelec, LMOPS, EA 4423, Metz (France); Bouchoule, Sophie; Patriarche, Gilles [LPN CNRS, UPR20, Marcoussis (France); Dupuis, Russell D. [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Salvestrini, Jean-Paul [UMI 2958, Georgia Tech-CNRS, Metz (France); Universite de Lorraine, LMOPS, EA 4423, Metz (France)

    2015-04-01

    In this work, wurtzite BAlN layers with boron composition as high as 12% were successfully grown by MOVPE. The growth was performed at 650 C and then annealed at 1020 C. Low temperature growth was used in order to alleviate B-rich phase poisoning under high TEB/III ratio. The growth was performed by continuous epitaxy as well as by flow-modulate epitaxy. BAlN single layers with clearly defined X-ray diffraction peaks were achieved on AlN templates which are appropriate substrates for deep UV devices, as well as on GaN templates to facilitate distinguishing of the XRD peak of BAlN from the substrate peak. The layer demonstrated columnar crystalline features and inherited wurtzite structure from substrates. Cross-section STEM image (bright field) of 75 nm thick BAlN layers containing 12% boron taken along the [11-2 0] zone axis. Zone A is lattice-oriented along c-axis and zone B has columnar structure; (b) higher magnification image for the top part of the layer; (c) higher magnification image for the film/substrate interface. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Relating performance of thin-film composite forward osmosis membranes to support layer formation and structure

    KAUST Repository

    Tiraferri, Alberto

    2011-02-01

    Osmotically driven membrane processes have the potential to treat impaired water sources, desalinate sea/brackish waters, and sustainably produce energy. The development of a membrane tailored for these processes is essential to advance the technology to the point that it is commercially viable. Here, a systematic investigation of the influence of thin-film composite membrane support layer structure on forward osmosis performance is conducted. The membranes consist of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation. By systematically varying the conditions used during the casting of the polysulfone layer, an array of support layers with differing structures was produced. The role that solvent quality, dope polymer concentration, fabric layer wetting, and casting blade gate height play in the support layer structure formation was investigated. Using a 1M NaCl draw solution and a deionized water feed, water fluxes ranging from 4 to 25Lm-2h-1 with consistently high salt rejection (>95.5%) were produced. The relationship between membrane structure and performance was analyzed. This study confirms the hypothesis that the optimal forward osmosis membrane consists of a mixed-structure support layer, where a thin sponge-like layer sits on top of highly porous macrovoids. Both the active layer transport properties and the support layer structural characteristics need to be optimized in order to fabricate a high performance forward osmosis membrane. © 2010 Elsevier B.V.

  13. Detection of copper ions from aqueous solutions using layered double hydroxides thin films deposited by PLD

    Science.gov (United States)

    Vlad, A.; Birjega, R.; Matei, A.; Luculescu, C.; Nedelcea, A.; Dinescu, M.; Zavoianu, R.; Pavel, O. D.

    2015-10-01

    Layered double hydroxides (LDHs) thin films with Mg-Al were deposited using pulsed laser deposition (PLD) technique. We studied the ability of our films to detect copper ions in aqueous solutions. Copper is known to be a common pollutant in water, originating from urban and industrial waste. Clay minerals, including layered double hydroxides (LDHs), can reduce the toxicity of such wastes by adsorbing copper. We report on the uptake of copper ions from aqueous solution on LDH thin films obtained via PLD. The obtained thin films were characterized using X-ray Diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The results in this study indicate that LDHs thin films obtained by PLD have potential as an efficient adsorbent for removing copper from aqueous solution.

  14. Crystallization study of amorphous sputtered NiTi bi-layer thin film

    Energy Technology Data Exchange (ETDEWEB)

    Mohri, Maryam, E-mail: mmohri@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe (Germany); Nili-Ahmadabadi, Mahmoud [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, University of Tehran, Tehran (Iran, Islamic Republic of); Chakravadhanula, Venkata Sai Kiran [Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe (Germany)

    2015-05-15

    The crystallization of Ni-rich/NiTiCu bi-layer thin film deposited by magnetron sputtering from two separate alloy targets was investigated. To achieve the shape memory effect, the NiTi thin films deposited at room temperature with amorphous structure were annealed at 773 K for 15, 30, and 60 min for crystallization. Characterization of the films was carried out by differential scanning calorimetry to indicate the crystallization temperature, grazing incidence X-ray diffraction to identify the phase structures, atomic force microscopy to evaluate surface morphology, scanning transmission electron microscopy to study the cross section of the thin films. The results show that the structure of the annealed thin films strongly depends on the temperature and time of the annealing. Crystalline grains nucleated first at the surface and then grew inward to form columnar grains. Furthermore, the crystallization behavior was markedly affected by composition variations. - Highlights: • A developed bi-layer Ni45TiCu5/Ni50.8Ti was deposited on Si substrate and crystallized. • During crystallization, The Ni{sub 45}TiCu{sub 5} layer is thermally less stable than the Ni-rich layer. • The activation energy is 302 and 464 kJ/mol for Cu-rich and Ni-rich layer in bi-layer, respectively.

  15. Perpendicular magnetic tunnel junction with thin CoFeB/Ta/Co/Pd/Co reference layer

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Huadong, E-mail: huadong@avalanche-technology.com; Malmhall, Roger; Wang, Zihui; Yen, Bing K; Zhang, Jing; Wang, Xiaobin; Zhou, Yuchen; Hao, Xiaojie; Jung, Dongha; Satoh, Kimihiro; Huai, Yiming [Avalanche Technology, 46600 Landing Parkway, Fremont, California 94538 (United States)

    2014-11-10

    Integration of high density spin transfer torque magnetoresistance random access memory requires a thin stack (less than 15 nm) of perpendicular magnetic tunnel junction (p-MTJ). We propose an innovative approach to solve this challenging problem by reducing the thickness and/or moment of the reference layer. A thin reference layer structure of CoFeB/Ta/Co/Pd/Co has 60% magnetic moment of the conventional thick structure including [Co/Pd] multilayers. We demonstrate that the perpendicular magnetization of the CoFeB/Ta/Co/Pd/Co structure can be realized by anti-ferromagnetically coupling to a pinned layer with strong perpendicular anisotropy via Ruderman-Kittel-Kasuya-Yosida exchange interaction. The pMTJ with thin CoFeB/Ta/Co/Pd/Co reference layer has a comparable TMR ratio (near 80%) as that with thick reference layer after annealing at 280 °C. The pMTJ with thin reference layer has a total thickness less than 15 nm, thereby significantly increasing the etching margin required for integration of high density pMTJ array on wafers with form factor of 300 mm and beyond.

  16. Determination of thin layer thickness from alpha particle energy spectra

    Energy Technology Data Exchange (ETDEWEB)

    Hnatowicz, V.; Kvitek, J. (Ceskoslovenska Akademie Ved, Prague. Ustav pro Elektrotechniku); Rybka, V.; Krejci, P. (Tesla, Prague (Czechoslovakia). Vyzkumny Ustav pro Sdelovaci Techniku); Pelikan, L. (Ceske Vysoke Uceni Technicke, Prague (Czechoslovakia). Fakulta Elektrotechnicka); Mikusik, P. (Ceskoslovenska Akademie Ved, Prague. Ustav Fyzikalni Chemie a Elektrochemie J. Heyrovskeho)

    1982-10-01

    A method which uses alpha particles from the /sup 10/B(n,alpha)/sup 7/Li nuclear reaction for the determination of surface layer thicknesses is described and experimentally checked. The thickness measurements can be performed on samples implanted with boron.

  17. Computationally efficient parabolic equation solutions to seismo-acoustic problems involving thin or low-shear elastic layers.

    Science.gov (United States)

    Metzler, Adam M; Collis, Jon M

    2013-04-01

    Shallow-water environments typically include sediments containing thin or low-shear layers. Numerical treatments of these types of layers require finer depth grid spacing than is needed elsewhere in the domain. Thin layers require finer grids to fully sample effects due to elasticity within the layer. As shear wave speeds approach zero, the governing system becomes singular and fine-grid spacing becomes necessary to obtain converged solutions. In this paper, a seismo-acoustic parabolic equation solution is derived utilizing modified difference formulas using Galerkin's method to allow for variable-grid spacing in depth. Propagation results are shown for environments containing thin layers and low-shear layers.

  18. Thin layer microcolony culture associated with PCR for early identification of Mycobacterium bovis

    Directory of Open Access Journals (Sweden)

    Tatiana Reis do Rosário

    2014-01-01

    Full Text Available The initial growth of mycobacteria from 49 samples of cattle and buffalo organs collected in commercial slaughterhouses was compared between modified Middlebrook 7H11 thin layer microcolony culture and Stonebrink medium used in the isolation of Mycobacterium bovis. Aliquots were decontaminated by Petroff's method, processed and cultured in both media. The identity of the acid-fast bacilli stained by Ziehl-Neelsen was confirmed by PCR. Optical microscopy showed that results of the early observation of Mycobacterium bovis colonies in thin layer culture were similar to those obtained in macroscopic observation of the colonies in Stonebrink medium. However, early observation of the colonies enabled early confirmation by PCR, given the shorter time to the visualization of colonies when thin layer culture was used (between the 12nd and 25th day of culture.

  19. Thin layer drying of cassava starch using continuous vibrated fluidized bed dryer

    Science.gov (United States)

    Suherman, Trisnaningtyas, Rona

    2015-12-01

    This paper present the experimental work and thin layer modelling of cassava starch drying in continuous vibrated fluidized bed dryer. The experimental data was used to validate nine thin layer models of drying curve. Cassava starch with 0.21 initial moisture content was dried in different air drying temperature (50°C, 55°C, 60°C, 65°C, 70°C), different weir height in bed (0 and 1 cm), and different solid feed flow (10 and 30 gr.minute-1). The result showed air dryer temperature has a significant effect on drying curve, while the weir height and solid flow rate are slightly. Based on value of R2, χ2, and RMSE, Page Model is the most accurate simulation for thin layer drying model of cassava starch.

  20. Enhanced second harmonic generation of MoS2 layers on a thin gold film.

    Science.gov (United States)

    Zeng, Jianhua; Yuan, Maohui; Yuan, Weiguang; Dai, Qiaofeng; Fan, Haihua; Lan, Sheng; Tie, Shaolong

    2015-08-28

    The linear and nonlinear optical properties of thin MoS2 layers exfoliated on an Au/SiO2 substrate were investigated both numerically and experimentally. It was found that the MoS2 layers with different thicknesses exhibited different colors on the gold film. The reflection spectra of the MoS2 layers with different thicknesses were calculated by using the finite-difference time-domain technique and the corresponding chromaticity coordinates were derived. The electric field enhancement factors at both the fundamental light and the second harmonic were calculated and the enhancement factors for second harmonic generation (SHG) were estimated for the MoS2 layers with different thicknesses. Different from the MoS2 layers on a SiO2/Si substrate where the maximum SHG was observed in the single-layer MoS2, the maximum SHG was achieved in the 17 nm-thick MoS2 layer on the Au/SiO2 substrate. As compared with the MoS2 layers on the SiO2/Si substrate, a significant enhancement in SHG was found for the MoS2 layers on the Au/SiO2 substrate due to the strong localization of the electric field. More interestingly, it was demonstrated experimentally that optical data storage can be realized by modifying the SHG intensity of a MoS2 layer through thinning its thickness.

  1. Enhanced second harmonic generation of MoS2 layers on a thin gold film.

    Science.gov (United States)

    Zeng, Jianhua; Yuan, Maohui; Yuan, Weiguang; Dai, Qiaofeng; Fan, Haihua; Lan, Sheng; Tie, Shaolong

    2015-08-28

    The linear and nonlinear optical properties of thin MoS2 layers exfoliated on an Au/SiO2 substrate were investigated both numerically and experimentally. It was found that the MoS2 layers with different thicknesses exhibited different colors on the gold film. The reflection spectra of the MoS2 layers with different thicknesses were calculated by using the finite-difference time-domain technique and the corresponding chromaticity coordinates were derived. The electric field enhancement factors at both the fundamental light and the second harmonic were calculated and the enhancement factors for second harmonic generation (SHG) were estimated for the MoS2 layers with different thicknesses. Different from the MoS2 layers on a SiO2/Si substrate where the maximum SHG was observed in the single-layer MoS2, the maximum SHG was achieved in the 17 nm-thick MoS2 layer on the Au/SiO2 substrate. As compared with the MoS2 layers on the SiO2/Si substrate, a significant enhancement in SHG was found for the MoS2 layers on the Au/SiO2 substrate due to the strong localization of the electric field. More interestingly, it was demonstrated experimentally that optical data storage can be realized by modifying the SHG intensity of a MoS2 layer through thinning its thickness. PMID:26204257

  2. Drift of scroll waves in thin layers caused by thickness features: asymptotic theory and numerical simulations.

    Science.gov (United States)

    Biktasheva, I V; Dierckx, H; Biktashev, V N

    2015-02-13

    A scroll wave in a very thin layer of excitable medium is similar to a spiral wave, but its behavior is affected by the layer geometry. We identify the effect of sharp variations of the layer thickness, which is separate from filament tension and curvature-induced drifts described earlier. We outline a two-step asymptotic theory describing this effect, including asymptotics in the layer thickness and calculation of the drift of so-perturbed spiral waves using response functions. As specific examples, we consider drift of scrolls along thickness steps, ridges, ditches, and disk-shaped thickness variations. Asymptotic predictions agree with numerical simulations.

  3. Preparation and recording characteristics of granular-type perpendicular magnetic recording media with thin intermediate layer

    International Nuclear Information System (INIS)

    Granular-type media with thin Ru intermediate layer were prepared on a highly oriented high-Bs FeCo soft underlayer (SUL). A CoPt-TiO2 recording layer on a Ru intermediate layer of only 2 nm had high-crystal orientation, high Hc of 6.5 kOe, and a high squareness ratio (SQ) of 0.99. The magnetic property of the SUL was also good. The recording performance was measured for the media with different Ru intermediate thicknesses by using a single-pole-type (SPT) head. The media had large reproduced output even for the Ru intermediate layer thickness of 2 nm

  4. Ultraviolet laser deposition of graphene thin films without catalytic layers

    KAUST Repository

    Sarath Kumar, S. R.

    2013-01-09

    In this letter, the formation of nanostructured graphene by ultraviolet laser ablation of a highly ordered pyrolytic graphite target under optimized conditions is demonstrated, without a catalytic layer, and a model for the growth process is proposed. Previously, graphene film deposition by low-energy laser (2.3 eV) was explained by photo-thermal models, which implied that graphene films cannot be deposited by laser energies higher than the C-C bond energy in highly ordered pyrolytic graphite (3.7 eV). Here, we show that nanostructured graphene films can in fact be deposited using ultraviolet laser (5 eV) directly over different substrates, without a catalytic layer. The formation of graphene is explained by bond-breaking assisted by photoelectronic excitation leading to formation of carbon clusters at the target and annealing out of defects at the substrate.

  5. Optical Layers for Thin-film Silicon Solar Cells

    OpenAIRE

    Cuony, Peter

    2011-01-01

    In this work we develop and analyze optical layers for use in Micromorph solar cells, a tandem configuration with an amorphous silicon top cell and a microcrystalline silicon bottom cell. The morphology of the front electrode has a decisive role in maximizing the efficiency of a solar cell. To reach a better understanding of the requirements for the front electrode surface, we present a wide range of morphologies that can be obtained with as-grown rou...

  6. STUDY ON DETERMINATION OF TRACE Fe BY Fe(Ⅱ)-VA THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

    Institute of Scientific and Technical Information of China (English)

    SONG Huanyu; YAN Yongsheng; WANG Yun

    2006-01-01

    A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe(Ⅱ) and VA was absorbed on the 717#resin and Fe was determined by making thin layer. This method had a high sensitivity (ε620=3.0×105 L/mol·cm), which was 15 times higher than that of liquid phase spectrophotometry. It had been proved a satisfactory precision (5.0μg Fe, n=6, RSD=1.8%). The trace Fe in natural water was determined and the recovery was 97%.

  7. Electroresistance effect in gold thin film induced by ionic-liquid-gated electric double layer

    International Nuclear Information System (INIS)

    Electroresistance effect was detected in a metallic thin film using ionic-liquid-gated electric-double-layer transistors (EDLTs). We observed reversible modulation of the electric resistance of a Au thin film. In this system, we found that an electric double layer works as a nanogap capacitor with 27 (-25) MV cm-1 of electric field by applying only 1.7 V of positive (negative) gate voltage. The experimental results indicate that the ionic-liquid-gated EDLT technique can be used for controlling the surface electronic states on metallic systems. (author)

  8. Anti-fogging and anti-frosting behaviors of layer-by-layer assembled cellulose derivative thin film

    Science.gov (United States)

    Shibraen, Mahmoud H. M. A.; Yagoub, Hajo; Zhang, Xuejian; Xu, Jian; Yang, Shuguang

    2016-05-01

    Two cellulose derivatives, quaternized cellulose (QC) and carboxymethyl cellulose (CMC), were layer-by-layer (LbL) assembled to prepare a thin film. QC was also LbL assembled with two synthetic polyelectrolytes, poly(acrylic acid) (PAA) and poly(styrene sulfonate) (PSS), separately. The anti-fogging and anti-frosting properties of the assembled films were studied. QC/CMC thin film exhibits anti-fogging and anti-frosting behaviors, whereas QC/PAA and QC/PSS films do not have capacity for anti-fogging and anti-frosting. The anti-fogging and anti-frosting properties of QC/CMC film are attributed to that water molecules can be quickly adsorbed into the matrix of the film. The water adsorption of QC/CMC film was illustrated by the optical thickness increment.

  9. Spotting 2D atomic layers on aluminum nitride thin films

    Science.gov (United States)

    Chandrasekar, Hareesh; Bharadwaj B, Krishna; Vaidyuala, Kranthi Kumar; Suran, Swathi; Bhat, Navakanta; Varma, Manoj; Raghavan, Srinivasan

    2015-10-01

    Substrates for 2D materials are important for tailoring their fundamental properties and realizing device applications. Aluminum nitride (AIN) films on silicon are promising large-area substrates for such devices in view of their high surface phonon energies and reasonably large dielectric constants. In this paper epitaxial layers of AlN on 2″ Si wafers have been investigated as a necessary first step to realize devices from exfoliated or transferred atomic layers. Significant thickness dependent contrast enhancements are both predicted and observed for monolayers of graphene and MoS2 on AlN films as compared to the conventional SiO2 films on silicon, with calculated contrast values approaching 100% for graphene on AlN as compared to 8% for SiO2 at normal incidences. Quantitative estimates of experimentally measured contrast using reflectance spectroscopy show very good agreement with calculated values. Transistors of monolayer graphene on AlN films are demonstrated, indicating the feasibility of complete device fabrication on the identified layers.

  10. Spotting 2D atomic layers on aluminum nitride thin films.

    Science.gov (United States)

    Chandrasekar, Hareesh; Bharadwaj B, Krishna; Vaidyuala, Kranthi Kumar; Suran, Swathi; Bhat, Navakanta; Varma, Manoj; Srinivasan Raghavan

    2015-10-23

    Substrates for 2D materials are important for tailoring their fundamental properties and realizing device applications. Aluminum nitride (AIN) films on silicon are promising large-area substrates for such devices in view of their high surface phonon energies and reasonably large dielectric constants. In this paper epitaxial layers of AlN on 2″ Si wafers have been investigated as a necessary first step to realize devices from exfoliated or transferred atomic layers. Significant thickness dependent contrast enhancements are both predicted and observed for monolayers of graphene and MoS2 on AlN films as compared to the conventional SiO2 films on silicon, with calculated contrast values approaching 100% for graphene on AlN as compared to 8% for SiO2 at normal incidences. Quantitative estimates of experimentally measured contrast using reflectance spectroscopy show very good agreement with calculated values. Transistors of monolayer graphene on AlN films are demonstrated, indicating the feasibility of complete device fabrication on the identified layers.

  11. Characterization of BLT thin films using MgO buffer layer for MFIS-FET

    International Nuclear Information System (INIS)

    The BLT thin film and MgO buffer layer were fabricated using a metalorganic decomposition method and the DC sputtering technique. The MgO thin film was deposited as a buffer layer on SiO2/Si and Bi3.25La0.75Ti3O12 (BLT) thin films were used as a ferroelectric layer. The electrical of the metal ferroelectric insulator semiconductor (MFIS) structure were investigated by varying the MgO layer thickness. Transmission electron microscopy (TEM) shows no interdiffusion and reaction that suppressed by using the MgO film as a buffer layer. The width of the memory window in the C-V curves for the MFIS structure decreased with increasing thickness of the MgO layer. Leakage current density decreased by about three orders of magnitude after using MgO buffer layer. The results show that the BLT and MgO-based MFIS structure is suitable for non-volatile memory FETs with large memory window

  12. Characterization of BLT thin films using MgO buffer layer for MFIS-FET

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyoung-Tae [School of Electrical and Electronic Engineering, Chungang University, 221, Huksuk-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of); Lee, Jung-Mi [School of Electrical and Electronic Engineering, Chungang University, 221, Huksuk-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of); Song, Sang-Hun [School of Electrical and Electronic Engineering, Chungang University, 221, Huksuk-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of); Kim, Chang-Il [School of Electrical and Electronic Engineering, Chungang University, 221, Huksuk-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of)]. E-mail: cikim@cau.ac.kr

    2005-03-22

    The BLT thin film and MgO buffer layer were fabricated using a metalorganic decomposition method and the DC sputtering technique. The MgO thin film was deposited as a buffer layer on SiO{sub 2}/Si and Bi{sub 3.25}La{sub 0.75}Ti{sub 3}O{sub 12} (BLT) thin films were used as a ferroelectric layer. The electrical of the metal ferroelectric insulator semiconductor (MFIS) structure were investigated by varying the MgO layer thickness. Transmission electron microscopy (TEM) shows no interdiffusion and reaction that suppressed by using the MgO film as a buffer layer. The width of the memory window in the C-V curves for the MFIS structure decreased with increasing thickness of the MgO layer. Leakage current density decreased by about three orders of magnitude after using MgO buffer layer. The results show that the BLT and MgO-based MFIS structure is suitable for non-volatile memory FETs with large memory window.

  13. Analysis of layer-by-layer thin-film oxide growth using RHEED and Atomic Force Microscopy

    Science.gov (United States)

    Adler, Eli; Sullivan, M. C.; Gutierrez-Llorente, Araceli; Joress, H.; Woll, A.; Brock, J. D.

    2015-03-01

    Reflection high energy electron diffraction (RHEED) is commonly used as an in situ analysis tool for layer-by-layer thin-film growth. Atomic force microscopy is an equally common ex situ tool for analysis of the film surface, providing visual evidence of the surface morphology. During growth, the RHEED intensity oscillates as the film surface changes in roughness. It is often assumed that the maxima of the RHEED oscillations signify a complete layer, however, the oscillations in oxide systems can be misleading. Thus, using only the RHEED maxima is insufficient. X-ray reflectivity can also be used to analyze growth, as the intensity oscillates in phase with the smoothness of the surface. Using x-ray reflectivity to determine the thin film layer deposition, we grew three films where the x-ray and RHEED oscillations were nearly exactly out of phase and halted deposition at different points in the growth. Pre-growth and post-growth AFM images emphasize the fact that the maxima in RHEED are not a justification for determining layer completion. Work conducted at the Cornell High Energy Synchrotron Source (CHESS) supported by NSF Awards DMR-1332208 and DMR-0936384 and the Cornell Center for Materials Research Shared Facilities are supported through DMR-1120296.

  14. Uniaxially aligned electrospun cellulose acetate nanofibers for thin layer chromatographic screening of hydroquinone and retinoic acid adulterated in cosmetics.

    Science.gov (United States)

    Tidjarat, Siripran; Winotapun, Weerapath; Opanasopit, Praneet; Ngawhirunpat, Tanasait; Rojanarata, Theerasak

    2014-11-01

    Uniaxially aligned cellulose acetate (CA) nanofibers were successfully fabricated by electrospinning and applied to use as stationary phase for thin layer chromatography. The control of alignment was achieved by using a drum collector rotating at a high speed of 6000 rpm. Spin time of 6h was used to produce the fiber thickness of about 10 μm which was adequate for good separation. Without any chemical modification after the electrospinning process, CA nanofibers could be readily devised for screening hydroquinone (HQ) and retinoic acid (RA) adulterated in cosmetics using the mobile phase consisting of 65:35:2.5 methanol/water/acetic acid. It was found that the separation run on the aligned nanofibers over a distance of 5 cm took less than 15 min which was two to three times faster than that on the non-aligned ones. On the aligned nanofibers, the masses of HQ and RA which could be visualized were 10 and 25 ng, respectively, which were two times lower than those on the non-aligned CA fibers and five times lower than those on conventional silica plates due to the appearance of darker and sharper of spots on the aligned nanofibers. Furthermore, the proposed method efficiently resolved HQ from RA and ingredients commonly found in cosmetic creams. Due to the satisfactory analytical performance, facile and inexpensive production process, uniaxially aligned electrospun CA nanofibers are promising alternative media for planar chromatography.

  15. Fullerenes as adhesive layers for mechanical peeling of metallic, molecular and polymer thin films.

    Science.gov (United States)

    Wieland, Maria B; Slater, Anna G; Mangham, Barry; Champness, Neil R; Beton, Peter H

    2014-01-01

    We show that thin films of C60 with a thickness ranging from 10 to 100 nm can promote adhesion between a Au thin film deposited on mica and a solution-deposited layer of the elastomer polymethyldisolaxane (PDMS). This molecular adhesion facilitates the removal of the gold film from the mica support by peeling and provides a new approach to template stripping which avoids the use of conventional adhesive layers. The fullerene adhesion layers may also be used to remove organic monolayers and thin films as well as two-dimensional polymers which are pre-formed on the gold surface and have monolayer thickness. Following the removal from the mica support the monolayers may be isolated and transferred to a dielectric surface by etching of the gold thin film, mechanical transfer and removal of the fullerene layer by annealing/dissolution. The use of this molecular adhesive layer provides a new route to transfer polymeric films from metal substrates to other surfaces as we demonstrate for an assembly of covalently-coupled porphyrins.

  16. Fullerenes as adhesive layers for mechanical peeling of metallic, molecular and polymer thin films

    Directory of Open Access Journals (Sweden)

    Maria B. Wieland

    2014-04-01

    Full Text Available We show that thin films of C60 with a thickness ranging from 10 to 100 nm can promote adhesion between a Au thin film deposited on mica and a solution-deposited layer of the elastomer polymethyldisolaxane (PDMS. This molecular adhesion facilitates the removal of the gold film from the mica support by peeling and provides a new approach to template stripping which avoids the use of conventional adhesive layers. The fullerene adhesion layers may also be used to remove organic monolayers and thin films as well as two-dimensional polymers which are pre-formed on the gold surface and have monolayer thickness. Following the removal from the mica support the monolayers may be isolated and transferred to a dielectric surface by etching of the gold thin film, mechanical transfer and removal of the fullerene layer by annealing/dissolution. The use of this molecular adhesive layer provides a new route to transfer polymeric films from metal substrates to other surfaces as we demonstrate for an assembly of covalently-coupled porphyrins.

  17. Effect of Oxide Buffer Layer on the Thermochromic Properties of VO2 Thin Films

    Science.gov (United States)

    Koo, Hyun; Xu, Lu; Ko, Kyeong-Eun; Ahn, Seunghyun; Chang, Se-Hong; Park, Chan

    2013-12-01

    VO2 thin films were deposited on soda lime glass substrates with ZnO, TiO2, SnO2, and CeO2 thin films applied as buffer layers between the VO2 films and the substrates in order to investigate the effect of buffer layer on the formation and the thermochromic properties of VO2 film. Buffer layers with thicknesses over 50 nm were found to affect the formation of VO2 film, which was confirmed by XRD spectra. By using ZnO, TiO2, and SnO2 buffer layers, monoclinic VO2 (VO2(M)) film was successfully fabricated on soda lime glass at 370 °C. On the contrary, films of VO2(B), which is known to have no phase transition near room temperature, were formed rather than VO2(M) when the film was deposited on CeO2 buffer layer at the same film deposition temperature. The excellent thermochromic properties of the films deposited on ZnO, TiO2, and SnO2 buffer layers were confirmed from the temperature dependence of electrical resistivity from room temperature to 80 °C. Especially, due to the tendency of ZnO thin film to grow with a high degree of preferred orientation on soda lime glass at low temperature, the VO2 film deposited on ZnO buffer layer exhibits the best thermochromic properties compared to those on other buffer layer materials used in this study. These results suggest that deposition of VO2 films on soda lime glass at low temperature with excellent thermochromic properties can be achieved by considering the buffer layer material having structural similarity with VO2. Moreover, the degree of crystallization of buffer layer is also related with that of VO2 film, and thus ZnO can be one of the most effective buffer layer materials.

  18. Design of a 1200-V Thin-Silicon-Layer p-Channel SOI LDMOS Device

    Institute of Scientific and Technical Information of China (English)

    胡盛东; 张玲; 罗小蓉; 张波; 李肇基; 吴丽娟

    2011-01-01

    A 1200-V thin-silicon-layer p-channel silicon-on-insulator(SOI)lateral double-diffused metal-oxide-semiconductor (LDMOS)transistor is designed.The device named INI SO1 p-LDMOS is characterized by a series of equidistant high concentration n+ islands inserted at the interface of a top silicon layer and a buried oxide layer.Accumulation-mode holes,caused by the electric potential dispersion between the device surface and the substrate,are located in the spacing between two neighboring n+ islands,and greatly enhance the electric field of the buried oxide layer and therefore,effectively increase the device breakdown voltage.Based on a 2-μm-thick buried oxide layer and a 1.5-μm-thick top silicon layer,a breakdown voltage of 1224 V is obtained,resulting in the high electric field(608 V/μm)of the buried oxide layer.%A 1200-V thin-silicon-layer p-channel silicon-on-insulator (SOI) lateral double-diffused metal-oxide-semiconductor (LDMOS) transistor is designed. The device named INI SOI p-LDMOS is characterized by a series of equidistant high concentration n+ islands inserted at the interface of a top silicon layer and a buried oxide layer. Accumulation-mode holes, caused by the electric potential dispersion between the device surface and the substrate, are located in the spacing between two neighboring n+ islands, and greatly enhance the electric field of the buried oxide layer and therefore, effectively increase the device breakdown voltage. Based on a 2-[im-thick buried oxide layer and a 1.5-um-thick top silicon layer, a breakdown voltage of 1224 V is obtained, resulting in the high electric field (608 V/\\im) of the buried oxide layer.

  19. Effects of ruthenium seed layer on the microstructure and spin dynamics of thin permalloy films

    International Nuclear Information System (INIS)

    The spin dynamics and microstructure properties of a sputtered 12 nm Ni81Fe19 thin film have been enhanced by the use of a ruthenium seed layer. Both the ferromagnetic resonance field and linewidth are enhanced dramatically as the thickness of ruthenium seed layer is increased. The surface anisotropy energy constant can also be largely tailored from 0.06 to 0.96 erg/cm−2 by changing the seed layer thickness. The changes to the dynamics magnetization properties are caused by both ruthenium seed layer induced changes in the Ni81Fe19 structure properties and surface topography properties. Roughness induced inhomogeneous linewidth broadening is also seen. The damping constant is highly tunable via the ruthenium thickness. This approach can be used to tailor both the structure and spin dynamic properties of thin Ni81Fe19 films over a wide range. And it may benefit the applications of spin dynamics and spin current based devices.

  20. Effects of ruthenium seed layer on the microstructure and spin dynamics of thin permalloy films

    Science.gov (United States)

    Jin, Lichuan; Zhang, Huaiwu; Tang, Xiaoli; Bai, Feiming; Zhong, Zhiyong

    2013-02-01

    The spin dynamics and microstructure properties of a sputtered 12 nm Ni81Fe19 thin film have been enhanced by the use of a ruthenium seed layer. Both the ferromagnetic resonance field and linewidth are enhanced dramatically as the thickness of ruthenium seed layer is increased. The surface anisotropy energy constant can also be largely tailored from 0.06 to 0.96 erg/cm-2 by changing the seed layer thickness. The changes to the dynamics magnetization properties are caused by both ruthenium seed layer induced changes in the Ni81Fe19 structure properties and surface topography properties. Roughness induced inhomogeneous linewidth broadening is also seen. The damping constant is highly tunable via the ruthenium thickness. This approach can be used to tailor both the structure and spin dynamic properties of thin Ni81Fe19 films over a wide range. And it may benefit the applications of spin dynamics and spin current based devices.

  1. Transmission electron microscopy study on ion-beam-synthesized amorphous Fe-Si thin layers

    Science.gov (United States)

    Naito, Muneyuki; Ishimaru, Manabu; Hirotsu, Yoshihiko; Valdez, James A.; Sickafus, Kurt E.

    2005-12-01

    Ion-beam-synthesized amorphous Fe-Si thin layers have been characterized using transmission electron microscopy (TEM) in combination with imaging plate techniques. Si single crystals with a (111) orientation were irradiated with 120keV Fe+ ions to a fluence of 4.0×1017cm-2 at cryogenic temperature (120K). Cross-sectional TEM observations indicated the formation of an amorphous bilayer on the topmost layer of the Si substrate. It was found that the upper layer is an amorphous Fe-Si with the composition, in terms of atomic ratio, of Fe /Si ˜1/2, while the lower one is an amorphous Si. Atomic pair-distribution functions extracted from microbeam electron diffraction patterns revealed that the nature of short-range order in amorphous Fe-Si thin layer can be well described by the atomic arrangements of crystalline iron silicides.

  2. Squeezing molecular thin alkane lubrication films: layering transition and wear

    OpenAIRE

    Sivebæk, Ion Marius; Samoilov, V. N.; Persson, B. N. J.

    2003-01-01

    The properties of alkane lubricants confined between two approaching solids are investigated by a model that accounts for the curvature and the elastic properties of the solid surfaces. We consider linear alkane molecules of different chain lengths, C3H8, C4H10, C8H18, C9H20, C10H22, C12H26, and C14H30 confined between smooth gold surfaces. In most cases we observe well defined molecular layers develop in the lubricant film when the width of the film is of the order of a few atomic diameters....

  3. Epitaxially grown polycrystalline silicon thin-film solar cells on solid-phase crystallised seed layers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei, E-mail: weili.unsw@gmail.com; Varlamov, Sergey; Xue, Chaowei

    2014-09-30

    Highlights: • Crystallisation kinetic is used to analyse seed layer surface cleanliness. • Simplified RCA cleaning for the seed layer can shorten the epitaxy annealing duration. • RTA for the seed layer can improve the quality for both seed layer and epi-layer. • Epitaxial poly-Si solar cell performance is improved by RTA treated seed layer. - Abstract: This paper presents the fabrication of poly-Si thin film solar cells on glass substrates using seed layer approach. The solid-phase crystallised P-doped seed layer is not only used as the crystalline template for the epitaxial growth but also as the emitter for the solar cell structure. This paper investigates two important factors, surface cleaning and intragrain defects elimination for the seed layer, which can greatly influence the epitaxial grown solar cell performance. Shorter incubation and crystallisation time is observed using a simplified RCA cleaning than the other two wet chemical cleaning methods, indicating a cleaner seed layer surface is achieved. Cross sectional transmission microscope images confirm a crystallographic transferal of information from the simplified RCA cleaned seed layer into the epi-layer. RTA for the SPC seed layer can effectively eliminate the intragrain defects in the seed layer and improve structural quality of both of the seed layer and the epi-layer. Consequently, epitaxial grown poly-Si solar cell on the RTA treated seed layer shows better solar cell efficiency, V{sub oc} and J{sub sc} than the one on the seed layer without RTA treatment.

  4. New Transmission Condition Accounting For Diffusion Anisotropy In Thin Layers Applied To Diffusion MRI

    OpenAIRE

    Caubet, Fabien; Haddar, Houssem; Li, Jing-Rebecca; Nguyen, Dang

    2014-01-01

    The Bloch-Torrey Partial Differential Equation (PDE) can be used to model the diffusion Magnetic Resonance Imaging (dMRI) signal in biological tissue. In this paper, we derive an Anisotropic Diffusion Transmission Condition (ADTC) for the Bloch-Torrey PDE that accounts for anisotropic diffusion inside thin layers. Such diffusion occurs, for example, in the myelin sheath surrounding the axons of neurons. This ADTC can be interpreted as an asymptotic model of order two with respect to the layer...

  5. Hidden thin layers of toxic diatoms in a coastal bay

    Science.gov (United States)

    Timmerman, Amanda H. V.; McManus, Margaret A.; Cheriton, O. M.; Cowen, Robert K.; Greer, Adam T.; Kudela, Raphael M.; Ruttenberg, Kathleen; Sevadjian, Jeff

    2014-03-01

    Harmful algal blooms (HABs) can threaten animal and human health through the production of toxins such as domoic acid. These blooms have become more frequent and toxic over the last few decades. In this study, we investigate the role that nutrients play in a toxic, subsurface bloom of Pseudo-nitzschia in northeastern Monterey Bay, California. Profilers and towed instruments were deployed and laboratory analyses of discrete water samples were conducted to describe the physical and biogeochemical conditions of the sampling site and to characterize the bloom. The subsurface Pseudo-nitzschia bloom occurred within a well-defined layer, containing high levels of domoic acid. In situ images taken within the layer revealed diatom flocs—indicators of nutrient stress. Nutrient ratios and alkaline phosphatase activity, commonly used to determine the nutritional status of phytoplankton, suggest that the Pseudo-nitzschia cells were phosphate stressed, and we speculate that this physiological stress led to increased toxicity of the bloom. Understanding how frequently blooms such as these are characterized by nutrient stress could improve our ability to predict the occurrence of HABs. With increased anthropogenic input of nutrients, such blooms could occur more often and with greater degrees of toxicity in the future.

  6. Buckling instability of a thin-layer rectilinear Couette flow

    CERN Document Server

    Slim, Anja; Mahadevan, L

    2011-01-01

    We analyse the buckling stability of a thin, viscous sheet when subject to simple shear, providing conditions for the onset of the dominant out-of-plane modes using two models: (i) an asymptotic theory for the dynamics of a viscous plate and (ii) the full Stokes equations. In either case, the plate is stabilised by a combination of viscous resistance, surface tension and buoyancy relative to an underlying denser fluid. In the limit of vanishing thickness, plates buckle at a shear rate $\\gamma/(\\mu d)$ independent of buoyancy, where 2d is the plate thickness, $\\gamma$ is the average surface tension between the upper and lower surfaces and $\\mu$ is the fluid viscosity. For thicker plates stabilised by an equal surface tension at the upper and lower surfaces, at and above onset, the most unstable mode has moderate wavelength, is stationary in the frame of the centre-line, spans the width of the plate with crests and troughs aligned at approximately $45^\\circ$ to the walls and closely resembles elastic shear mode...

  7. Characterization of pulsed laser deposited chalcogenide thin layers

    International Nuclear Information System (INIS)

    In this work we report on pulsed laser deposition (PLD) of chalcogenide thin films from the systems (AsSe)100-xAgIx and (AsSe)100-xAgx for sensing applications. A KrF* excimer laser (λ = 248 nm; τFWHM = 25 ns) was used to ablate the targets that had been prepared from the synthesised chalcogenide materials. The films were deposited in either vacuum (4 x 10-4 Pa) or argon (5 Pa) on silicon and glass substrates kept at room temperature. The basic properties of the films, including their morphology, topography, structure, and composition were characterised by complementary techniques. Investigations by X-ray diffraction (XRD) confirmed the amorphous nature of the films, as no strong diffraction reflections were found. The film composition was studied by energy dispersive X-ray (EDX) spectroscopy. The morphology of the films investigated by scanning electron microscopy (SEM), revealed a particulate-covered homogeneous surface, typical of PLD. Topographical analyses by atomic force microscopy (AFM) showed that the particulate size was slightly larger in Ar than in vacuum. The uniform surface areas were rather smooth, with root mean square (rms) roughness increasing up to several nanometers with the AgI or Ag doping. Based upon the results from the comprehensive investigation of the basic properties of the chalcogenide films prepared by PLD and their dependence on the process parameters, samples with appropriate sorption properties can be selected for possible applications in cantilever gas sensors

  8. Epitaxially grown polycrystalline silicon thin-film solar cells on solid-phase crystallised seed layers

    Science.gov (United States)

    Li, Wei; Varlamov, Sergey; Xue, Chaowei

    2014-09-01

    This paper presents the fabrication of poly-Si thin film solar cells on glass substrates using seed layer approach. The solid-phase crystallised P-doped seed layer is not only used as the crystalline template for the epitaxial growth but also as the emitter for the solar cell structure. This paper investigates two important factors, surface cleaning and intragrain defects elimination for the seed layer, which can greatly influence the epitaxial grown solar cell performance. Shorter incubation and crystallisation time is observed using a simplified RCA cleaning than the other two wet chemical cleaning methods, indicating a cleaner seed layer surface is achieved. Cross sectional transmission microscope images confirm a crystallographic transferal of information from the simplified RCA cleaned seed layer into the epi-layer. RTA for the SPC seed layer can effectively eliminate the intragrain defects in the seed layer and improve structural quality of both of the seed layer and the epi-layer. Consequently, epitaxial grown poly-Si solar cell on the RTA treated seed layer shows better solar cell efficiency, Voc and Jsc than the one on the seed layer without RTA treatment.

  9. Layered double hydroxides/polymer thin films grown by matrix assisted pulsed laser evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Birjega, R.; Matei, A.; Mitu, B.; Ionita, M.D.; Filipescu, M.; Stokker-Cheregi, F.; Luculescu, C.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 77125 Bucharest–Magurele (Romania); Zavoianu, R.; Pavel, O.D. [University of Bucharest, Faculty of Chemistry, Department of Chemical Technology and Catalysis, 4-12 Regina Elisabeta Bd., Bucharest (Romania); Corobea, M.C. [National R. and S. Institute for Chemistry and Petrochemistry, ICECHIM, 202 Splaiul Independentei Str., CP-35-274, 060021, Bucharest (Romania)

    2013-09-30

    Due to their highly tunable properties, layered double hydroxides (LDHs) are an emerging class of the favorably layered crystals used for the preparation of multifunctional polymer/layered crystal nanocomposites. In contrast to cationic clay materials with negatively charge layers, LDHs are the only host lattices with positively charged layers (brucite-like), with interlayer exchangeable anions and intercalated water. In this work, the deposition of thin films of Mg and Al based LDH/polymers nanocomposites by laser techniques is reported. Matrix assisted pulsed laser evaporation was the method used for thin films deposition. The Mg–Al LDHs capability to act as a host for polymers and to produce hybrid LDH/polymer films has been investigated. Polyethylene glycol with different molecular mass compositions and ethylene glycol were used as polymers. The structure and surface morphology of the deposited LDH/polymers films were examined by X-ray diffraction, Fourier transform infra-red spectroscopy, atomic force microscopy and scanning electron microscopy. - Highlights: • Hybrid composites deposited by matrix assisted pulsed laser evaporation (MAPLE). • Mg–Al layered double hydroxides (LDH) and polyethylene glycol (PEG) are used. • Mixtures of PEG1450 and LDH were deposited by MAPLE. • Deposited thin films preserve the properties of the starting material. • The film wettability can be controlled by the amount of PEG.

  10. Tandem organic light-emitting diode with a molybdenum tri-oxide thin film interconnector layer

    Institute of Scientific and Technical Information of China (English)

    Lu Fei-Ping; Wang Qian; Zhou Xiang

    2013-01-01

    A 10-nm-thick molybdenum tri-oxide (MoO3) thin film was used as the interconnector layer in tandem organic lightemitting devices (OLEDs).The tandem OLEDs with two identical emissive units consisting of N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (NPB) / tris(8-hydroxyquinoline) aluminum (Alq3) exhibited current efficiency-current density characteristics superior to the conventional single-unit devices.At 20 mA/cm2,the current efficiency of the tandem OLEDs using the interconnector layers of MoO3 thin film was about 4.0 cd/A,which is about twice that of the corresponding conventional single-unit device (1.8 cd/A).The tandem OLED showed a higher power efficiency than the conventional single-unit device for luminance over 1200 cd/m2.The experimental results demonstrated that a MoO3 thin film with a proper thickness can be used as an effective interconnector layer in tandem OLEDs.Such an interconnector layer can be easily fabricated by simple thermal evaporation,greatly simplifying the device processing and fabrication processes required by previously reported interconnector layers.A possible explanation was proposed for the carrier generation of the MoO3 interconnector layer.

  11. Nano-oxide thin films deposited via atomic layer deposition on microchannel plates.

    Science.gov (United States)

    Yan, Baojun; Liu, Shulin; Heng, Yuekun

    2015-01-01

    Microchannel plate (MCP) as a key part is a kind of electron multiplied device applied in many scientific fields. Oxide thin films such as zinc oxide doped with aluminum oxide (ZnO:Al2O3) as conductive layer and pure aluminum oxide (Al2O3) as secondary electron emission (SEE) layer were prepared in the pores of MCP via atomic layer deposition (ALD) which is a method that can precisely control thin film thickness on a substrate with a high aspect ratio structure. In this paper, nano-oxide thin films ZnO:Al2O3 and Al2O3 were prepared onto varied kinds of substrates by ALD technique, and the morphology, element distribution, structure, and surface chemical states of samples were systematically investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoemission spectroscopy (XPS), respectively. Finally, electrical properties of an MCP device as a function of nano-oxide thin film thickness were firstly studied, and the electrical measurement results showed that the average gain of MCP was greater than 2,000 at DC 800 V with nano-oxide thin film thickness approximately 122 nm. During electrical measurement, current jitter was observed, and possible reasons were preliminarily proposed to explain the observed experimental phenomenon.

  12. Thin hydroxyapatite surface layers on titanium produced by ion implantation

    CERN Document Server

    Baumann, H; Bilger, G; Jones, D; Symietz, I

    2002-01-01

    In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (alpha,alpha) backscattering and the resonant nuclear reaction sup 1 H( sup 1 sup 5 N,alpha gamma) sup 1 sup 2 C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of m...

  13. Nonlinear acoustic response in thin oxide layers on fused silica

    International Nuclear Information System (INIS)

    Nonlinear mechanical properties of layered systems of Ta2O5 and TiO2 films deposited on fused silica by reactive evaporation (RE), reactive ion plating (IP) and spin coating (SC) are investigated by means of an ultrasonic technique. The coatings with thickness of 100 nm possess differences in density and crystal structure, due to the different deposition conditions. The nonlinear acoustic response of the film/substrate systems depends on film material. Differences are observed in respect to film density as obtained by the alternate deposition methods. The origin of the differences in nonlinear acoustic response of the samples is discussed. The results are correlated to adhesion properties of the films determined by a scratch-test method

  14. Computer-controlled preparation of thin tungsten layers

    International Nuclear Information System (INIS)

    Tungsten layers of 1-6 mg/cm2 with diameters of 10 mm are needed as heavy-ion targets and as flat or domed windows for in-beam ion sources. They are prepared by a high-vacuum evaporation-deposition process carried out in a computer-controlled apparatus. The tungsten, placed in the water-cooled crucible of an electron-beam gun, is gradually heated and evaporates at about its melting point (Tm=3643 K). The tungsten is deposited onto 9 mg/cm2 copper backings which are preheated by the thermal radiation from the evaporant. The deposition rate is controlled by a quartz crystal monitor. After the high-vacuum deposition process, the copper backings are removed by selective etching and the self-supported tungsten foils are characterized by their areal mass. The features of the commercially available evaporation unit used are discussed by way of this deposition process. (orig.)

  15. Fabrication of graphene thin films based on layer-by-layer self-assembly of functionalized graphene nanosheets.

    Science.gov (United States)

    Park, Je Seob; Cho, Sung Min; Kim, Woo-Jae; Park, Juhyun; Yoo, Pil J

    2011-02-01

    In this study, we present a facile means of fabricating graphene thin films via layer-by-layer (LbL) assembly of charged graphene nanosheets (GS) based on electrostatic interactions. To this end, graphite oxide (GO) obtained from graphite powder using Hummers method is chemically reduced to carboxylic acid-functionalized GS and amine-functionalized GS to perform an alternate LbL deposition between oppositely charged GSs. Specifically, for successful preparation of positively charged GS, GOs are treated with an intermediate acyl-chlorination reaction by thionyl chloride and a subsequent amidation reaction in pyridine, whereby a stable GO dispersibility can be maintained within the polar reaction solvent. As a result, without the aid of additional hybridization with charged nanomaterials or polyelectrolytes, the oppositely charged graphene nanosheets can be electrostatically assembled to form graphene thin films in an aqueous environment, while obtaining controllability over film thickness and transparency. Finally, the electrical property of the assembled graphene thin films can be enhanced through a thermal treatment process. Notably, the introduction of chloride functions during the acyl-chlorination reaction provides the p-doping effect for the assembled graphene thin films, yielding a sheet resistance of 1.4 kΩ/sq with a light transmittance of 80% after thermal treatment. Since the proposed method allows for large-scale production as well as elaborate manipulation of the physical properties of the graphene thin films, it can be potentially utilized in various applications, such as transparent electrodes, flexible displays and highly sensitive biosensors. PMID:21207942

  16. Residual stress fields in sol-gel-derived thin TiO2 layers

    NARCIS (Netherlands)

    Teeuw, D.H.J.; Haas, M. de; Hosson, J.Th.M. De

    1999-01-01

    This paper discusses the induction of residual stresses during the curing process of thin titania layers, which are derived using a sol-gel process. During this process, stresses may build up in the spinning stage, the drying stage, and the consolidation stage. The magnitude and character of these s

  17. A mass transfer model of ethanol emission from thin layers of corn silage

    Science.gov (United States)

    A mass transfer model of ethanol emission from thin layers of corn silage was developed and validated. The model was developed based on data from wind tunnel experiments conducted at different temperatures and air velocities. Multiple regression analysis was used to derive an equation that related t...

  18. Thin layer activation analysis of α induced reactions for surface wear studies in some natural isotopes

    International Nuclear Information System (INIS)

    The thin layer activation technique is widely used to study surface wear and erosion by employing medium energy, light charged particle accelerators in the micrometer range. In the present work, TLA technique has been explored using gamma spectroscopy for a large number of reactions in several isotopes, which may be of interest for the reactor technology

  19. A templated electrosynthesis of macroporous NiAl layered double hydroxides thin films.

    Science.gov (United States)

    Prevot, Vanessa; Forano, Claude; Khenifi, Aicha; Ballarin, Barbara; Scavetta, Erika; Mousty, Christine

    2011-02-14

    Colloidal crystals of polystyrene (PS) beads self-assembled on Pt electrode were used as a sacrificial template to electrosynthesis thin films of macroporous Layered Double Hydroxides (LDH). Such nanostructured materials display a high internal surface area and porosity leading to enhanced electrochemical performance. PMID:21125133

  20. Growth and characterization of highly Yb3+doped KY(WO4)2 thin layers

    NARCIS (Netherlands)

    Aravazhi, S.; Geskus, D.; Dalfsen, van K.; Günther, D.; Pollnau, M.

    2011-01-01

    Highly Yb-doped, lattice-matched layers of potassium double tungstates with different compositions were grown on undoped KY(WO4)2 substrates. Structural and optical investigations confirmed their high quality. Applications are in high-gain amplifiers and thin-disk lasers.

  1. Boundary Layer Flow over a Continuously Moving Thin Needle in a Parallel Free Stream

    Institute of Scientific and Technical Information of China (English)

    Anuar Ishak; Roslinda Nazar; Ioan Pop

    2007-01-01

    We investigate the boundary-layer flow on a moving isothermal thin needle parallel to a moving stream. The governing equations are solved numerically by a finite-difference method. Dual solutions are found to exist when the needle and the free stream move in the opposite directions.

  2. Bearing Capacity of Footings on Thin Layer of Sand on Soft Cohesive Soil

    DEFF Research Database (Denmark)

    Philipsen, J.; Sørensen, Carsten S.

    2004-01-01

    This paper contains the results of some numerical calculations performed with the aim to determine the bearing capacities of footings placed on a thin layer of sand underlain by soft cohesive soil. During the last 30-35 years different analytical and empirical calculation methods for this situation...

  3. Spatial atmospheric atomic layer deposition of InxGayZnzO for thin film transistors

    NARCIS (Netherlands)

    Illiberi, A.; Cobb, B.; Sharma, A.; Grehl, T.; Brongersma, H.; Roozeboom, F.; Gelinck, G.; Poodt, P.

    2015-01-01

    We have investigated the nucleation and growth of InGaZnO thin films by spatial atmospheric atomic layer deposition. Diethyl zinc (DEZ), trimethyl indium (TMIn), triethyl gallium (TEGa), and water were used as Zn, In, Ga and oxygen precursors, respectively. The vaporized metal precursors have been c

  4. A thin layer fiber-coupled luminescence dosimeter based on Al2O3:C

    DEFF Research Database (Denmark)

    Klein, F.A.; Greilich, Steffen; Andersen, Claus Erik;

    2011-01-01

    In this paper we present a fiber-coupled luminescent Al2O3:C dosimeter probe with high spatial resolution (0.1 mm). It is based on thin layers of Al2O3:C crystal powder and a UV-cured acrylate monomer composition. The fabrication of the thin layers is described in detail. No influence of the intr......In this paper we present a fiber-coupled luminescent Al2O3:C dosimeter probe with high spatial resolution (0.1 mm). It is based on thin layers of Al2O3:C crystal powder and a UV-cured acrylate monomer composition. The fabrication of the thin layers is described in detail. No influence...... without sensitivity corrections. For protons, a relative luminescence efficiency hHCP of 0.715 0.014 was found in the Bragg peak. For carbon ions, a value of 0.498 0.001 was found in the entrance channel, 0.205 0.015 in the Bragg peak, and a mean of 0.413 0.050 in the tail region. The mean range...

  5. Performance improvement in pentacene organic thin film transistors by inserting a C60 ultrathin layer

    Institute of Scientific and Technical Information of China (English)

    Sun Qin-Jun; Xu Zheng; Zhao Su-Ling; Zhang Fu-Jun; Gao Li-Yan

    2011-01-01

    The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C60 modification,the injection harrier is lowered and the contact resistance is reduced. Thus, the field-effect mobility increases from 0.12to 0.52 cm2/(V.s). It means that inserting a C60 ultra thin layer is a good method to improve the organic thin film transistor (OTFT) performance. The output curve is simulated by using a charge drift model. Considering the contact of OTFTs should be carried out.

  6. Density measurement of thin layers by electron energy loss spectroscopy (EELS).

    Science.gov (United States)

    Thomas, Jürgen; Ramm, Jürgen; Gemming, Thomas

    2013-07-01

    A method to measure the density of thin layers is presented which utilizes electron energy loss spectroscopy (EELS) techniques within a transmission electron microscope. The method is based on the acquisition of energy filtered images in the low loss region as well as of an element distribution map using core loss edges. After correction of multiple inelastic scattering effects, the intensity of the element distribution map is proportional to density and thickness. The dependence of the intensities of images with low energy loss electrons on the density is different from that. This difference allows the calculation of the relative density pixel by pixel and to determine lateral density gradients or fluctuations in thin films without relying on a constant specimen thickness. The method is demonstrated at thin carbon layers produced with density gradients.

  7. Growth and optical characteristics of high-quality ZnO thin films on graphene layers

    Directory of Open Access Journals (Sweden)

    Suk In Park

    2015-01-01

    Full Text Available We report the growth of high-quality, smooth, and flat ZnO thin films on graphene layers and their photoluminescence (PL characteristics. For the growth of high-quality ZnO thin films on graphene layers, ZnO nanowalls were grown using metal-organic vapor-phase epitaxy on oxygen-plasma treated graphene layers as an intermediate layer. PL measurements were conducted at low temperatures to examine strong near-band-edge emission peaks. The full-width-at-half-maximum value of the dominant PL emission peak was as narrow as 4 meV at T = 11 K, comparable to that of the best-quality films reported previously. Furthermore, the stimulated emission of ZnO thin films on the graphene layers was observed at the low excitation energy of 180 kW/cm2 at room temperature. Their structural and optical characteristics were investigated using X-ray diffraction, transmission electron microscopy, and PL spectroscopy.

  8. Growth and optical characteristics of high-quality ZnO thin films on graphene layers

    Energy Technology Data Exchange (ETDEWEB)

    Park, Suk In; Tchoe, Youngbin; Baek, Hyeonjun; Hyun, Jerome K.; Yi, Gyu-Chul, E-mail: njkim36@gmail.com, E-mail: gcyi@snu.ac.kr [Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 151-747 (Korea, Republic of); Heo, Jaehyuk [Advanced Development Team, LED Business, Samsung Electronics Co., Ltd., San#24 Nongseo-Dong, Giheung-Gu, Yongin-City, Gyeonggi-Do 446–711 (Korea, Republic of); Jo, Janghyun; Kim, Miyoung [Department of Materials Science and Engineering, Seoul National University, Seoul 151–744 (Korea, Republic of); Kim, Nam-Jung, E-mail: njkim36@gmail.com, E-mail: gcyi@snu.ac.kr [Department of Physics and Chemistry, Korea Military Academy, Seoul (Korea, Republic of)

    2015-01-01

    We report the growth of high-quality, smooth, and flat ZnO thin films on graphene layers and their photoluminescence (PL) characteristics. For the growth of high-quality ZnO thin films on graphene layers, ZnO nanowalls were grown using metal-organic vapor-phase epitaxy on oxygen-plasma treated graphene layers as an intermediate layer. PL measurements were conducted at low temperatures to examine strong near-band-edge emission peaks. The full-width-at-half-maximum value of the dominant PL emission peak was as narrow as 4 meV at T = 11 K, comparable to that of the best-quality films reported previously. Furthermore, the stimulated emission of ZnO thin films on the graphene layers was observed at the low excitation energy of 180 kW/cm{sup 2} at room temperature. Their structural and optical characteristics were investigated using X-ray diffraction, transmission electron microscopy, and PL spectroscopy.

  9. High-performance thin layer chromatographic quantification of bioactive psoralen and daidzein in leaves of Ficus carica L.

    Science.gov (United States)

    Ali, B; Mujeeb, M; Aeri, V; Mir, S R; Ahmad, S; Siddique, N A; Faiyazuddin, M; Shakeel, F

    2011-10-01

    This study was undertaken to quantify psoralen and daidzein by high-performance thin layer chromatography (HPTLC). The methanolic extract of 10 mg mL(-1) concentration solution was prepared for HPTLC quantification of psoralen and daidzein. HPTLC aluminium-backed plates coated with 0.2 mm layers of silica gel 60 F(254) were used as the stationary phase. The working standard solution of psoralen and daidzein was applied along with the test sample solution by means of Camag Linomat IV sample applicator. R (f) values of psoralen and daidzein were found to be 0.60 and 0.88, whilst as their percentage values in methanolic extract were found to be 3.02% and 5.64% (w/w), respectively. A simple quantitative estimation method of psoralen and daidzein by HPTLC is reported that can be used for the quality control of marketed preparations containing Ficus carica. However, further study is warranted to isolate and quantify active constituents present in the leaves of F. carica by sophisticated techniques.

  10. On elastic waves in an thinly-layered laminated medium with stress couples under initial stress

    Directory of Open Access Journals (Sweden)

    P. Pal Roy

    1988-01-01

    Full Text Available The present work is concerned with a simple transformation rule in finding out the composite elastic coefficients of a thinly layered laminated medium whose bulk properties are strongly anisotropic with a microelastic bending rigidity. These elastic coefficients which were not known completely for a layered laminated structure, are obtained suitably in terms of initial stress components and Lame's constants λi, μi of initially isotropic solids. The explicit solutions of the dynamical equations for a prestressed thinly layered laminated medium under horizontal compression in a gravity field are derived. The results are discussed specifying the effects of hydrostatic, deviatoric and couple stresses upon the characteristic propagation velocities of shear and compression wave modes.

  11. Noninvasive analysis of thin turbid layers using microscale spatially offset Raman spectroscopy.

    Science.gov (United States)

    Conti, Claudia; Realini, Marco; Colombo, Chiara; Sowoidnich, Kay; Afseth, Nils Kristian; Bertasa, Moira; Botteon, Alessandra; Matousek, Pavel

    2015-06-01

    Here, we demonstrate, for the first time, the extension of applicability of recently developed microscale spatially offset Raman spectroscopy (SORS), micro-SORS, from the area of cultural heritage to a wider range of analytical problems involving thin, tens of micrometers thick diffusely scattering turbid layers. The method can be applied in situations where a high turbidity of layers prevents the deployment of conventional confocal Raman microscopy with its depth resolving capability. The method was applied successfully to detect noninvasively the presence of thin, highly turbid layers within polymers, wheat seeds, and paper. An invasive, cross sectional analysis confirmed the micro-SORS findings. Micro-SORS represents a new Raman imaging modality expanding the portfolio of noninvasive, chemically specific analytical tools.

  12. Treatment of ice cover and other thin elastic layers with the parabolic equation method.

    Science.gov (United States)

    Collins, Michael D

    2015-03-01

    The parabolic equation method is extended to handle problems involving ice cover and other thin elastic layers. Parabolic equation solutions are based on rational approximations that are designed using accuracy constraints to ensure that the propagating modes are handled properly and stability constrains to ensure that the non-propagating modes are annihilated. The non-propagating modes are especially problematic for problems involving thin elastic layers. It is demonstrated that stable results may be obtained for such problems by using rotated rational approximations [Milinazzo, Zala, and Brooke, J. Acoust. Soc. Am. 101, 760-766 (1997)] and generalizations of these approximations. The approach is applied to problems involving ice cover with variable thickness and sediment layers that taper to zero thickness.

  13. Effect of tethering on the surface dynamics of a thin polymer melt layer.

    Science.gov (United States)

    Uğur, Gökçe; Akgun, Bulent; Jiang, Zhang; Narayanan, Suresh; Satija, Sushil; Foster, Mark D

    2016-06-28

    The surface height fluctuations of a layer of low molecular weight (2.2k) untethered perdeuterated polystyrene (dPS) chains adjacent to a densely grafted polystyrene brush are slowed dramatically. Due to the interpenetration of the brush with the layer of "untethered chains" a hydrodynamic continuum theory can only describe the fluctuations when the effective thickness of the film is taken to be that which remains above the swollen brush. The portion of the film of initially untethered chains that interpenetrates with the brush becomes so viscous as to effectively play the role of a rigid substrate. Since these hybrid samples containing a covalently tethered layer at the bottom do not readily dewet, and are more robust than thin layers of untethered short chains on rigid substrates, they provide a route for tailoring polymer layer surface properties such as wetting, adhesion and friction. PMID:27222250

  14. Zinc-oxide charge trapping memory cell with ultra-thin chromium-oxide trapping layer

    Directory of Open Access Journals (Sweden)

    Nazek El-Atab

    2013-11-01

    Full Text Available A functional zinc-oxide based SONOS memory cell with ultra-thin chromium oxide trapping layer was fabricated. A 5 nm CrO2 layer is deposited between Atomic Layer Deposition (ALD steps. A threshold voltage (Vt shift of 2.6V was achieved with a 10V programming voltage. Also for a 2V Vt shift, the memory with CrO2 layer has a low programming voltage of 7.2V. Moreover, the deep trapping levels in CrO2 layer allows for additional scaling of the tunnel oxide due to an increase in the retention time. In addition, the structure was simulated using Physics Based TCAD. The results of the simulation fit very well with the experimental results providing an understanding of the charge trapping and tunneling physics.

  15. Estimation of optical constants of a bio-thin layer (onion epidermis), using SPR spectroscopy

    International Nuclear Information System (INIS)

    We estimate the optical constants of a biological thin layer (Allium cepa) by surface plasmon resonance (SPR) spectroscopy. For this study, the fresh inner thin epidermis of an onion bulb was used and stacked directly on gold (Au) and silver (Ag) film surfaces in order to identify the shift in SPR mode of each metal film at an operating wavelength of 632.8 nm. The thickness and dielectric constants of the biological thin layer were determined by matching the experimental SPR curves to theoretical ones. The thickness and roughness of bare Au and Ag thin films were also measured by atomic force microscopy (AFM); the results of which are in good agreement with those obtained through experiment. Due to the high surface roughness of the natural onion epidermis layer, AFM could not measure the exact thickness of an onion epidermis. It is estimated that the value of the real part of the dielectric constant of an onion epidermis is between the dielectric constants of water and air. (paper)

  16. Spectroscopic investigations on thin adhesive layers in multi-material laminates.

    Science.gov (United States)

    Voronko, Yuliya; Chernev, Boril S; Eder, Gabriele C

    2014-01-01

    Three different spectroscopic approaches, Raman linescans, Raman imaging, and attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) imaging were evaluated for the visualization of the thin adhesive layers (3-6 μm) present in polymeric photovoltaic backsheets. The cross-sections of the multilayer laminates in the original, weathered, and artificially aged samples were investigated spectroscopically in order to describe the impact of the environmental factors on the evenness and thickness of the adhesive layers. All three methods were found to be suitable tools to detect and visualize these thin layers within the original and aged polymeric laminates. However, as the adhesive layer is not very uniform in thickness and partly disintegrates upon weathering and/or artificial aging, Raman linescans yield only qualitative information and do not allow for an estimation of the layer thickness. Upon increasing the measuring area by moving from one-dimensional linescans to two-dimensional Raman images, a much better result could be achieved. Even though a longer measuring time has to be taken into account, the information on the uniformity and evenness of the adhesive layer obtainable using the imaging technique is much more comprehensive. Although Raman spectroscopy is known to have the superior lateral resolution as compared with ATR FT-IR spectroscopy, the adhesive layers of the samples used within this study (layer thickness 3-6 μm) could also be detected and visualized by applying the ATR FT-IR spectroscopic imaging method. However, the analysis of the images was quite a demanding task, as the thickness of the adhesive layer was in the region of the resolution limit of this method. The information obtained for the impact of artificial aging and weathering on the adhesive layer obtained using Raman imaging and ATR FT-IR imaging was in good accordance.

  17. Layer-by-layer assembly of thin organic films on PTFE activated by cold atmospheric plasma

    Directory of Open Access Journals (Sweden)

    Tóth András

    2014-12-01

    Full Text Available An air diffuse coplanar surface barrier discharge is used to activate the surface of polytetrafluoroethylene (PTFE samples, which are subsequently coated with polyvinylpyrrolidone (PVP and tannic acid (TAN single, bi- and multilayers, respectively, using the dip-coating method. The surfaces are characterized by X-ray Photoelectron Spectroscopy (XPS, Attenuated Total Reflection – Fourier Transform Infrared Spectroscopy (ATR-FTIR and Atomic Force Microscopy (AFM. The XPS measurements show that with plasma treatment the F/C atomic ratio in the PTFE surface decreases, due to the diminution of the concentration of CF2 moieties, and also oxygen incorporation through formation of new C–O, C=O and O=C–O bonds can be observed. In the case of coated samples, the new bonds indicated by XPS show the bonding between the organic layer and the surface, and thus the stability of layers, while the gradual decrease of the concentration of F atoms with the number of deposited layers proves the creation of PVP/TAN bi- and multi-layers. According to the ATR-FTIR spectra, in the case of PVP/TAN multilayer hydrogen bonding develops between the PVP and TAN, which assures the stability of the multilayer. The AFM lateral friction measurements show that the macromolecular layers homogeneously coat the plasma treated PTFE surface.

  18. Thin-shell wormholes with a double layer in quadratic F(R) gravity

    CERN Document Server

    Eiroa, Ernesto F

    2016-01-01

    We present a family of spherically symmetric Lorentzian wormholes in quadratic F(R) gravity, with a thin shell of matter corresponding to the throat. At each side of the shell the geometry has a different constant value of the curvature scalar R. The junction conditions determine the equation of state between the pressure and energy density at the throat, where a double layer is also located. We analyze the stability of the configurations under perturbations preserving the spherical symmetry. In particular, we study thin-shell wormholes with mass and charge. We find that there exist values of the parameters for which stable static solutions are possible.

  19. High mobility organic thin-film transistors based on p-p heterojunction buffer layer

    Science.gov (United States)

    Qian, Xianrui; Wang, Tong; Yan, Donghang

    2013-10-01

    The p-p heterojunction of 5, 6, 11, 12-tetraphenylnaphthacene/vanadyl phthalocyanine, which has been used as the buffer layer, is demonstrated. The highest field-effect mobility is 5.1 cm2/Vs, which is one of the highest reported for polycrystalline rubrene thin film transistors. Current versus voltage characteristics of heterojunction diodes are utilized to investigate the charge injection mechanism, revealing the factors that bring about the improvement of carrier injection and the reduction of contact resistance. These results suggest that our approach is very promising to fabricate high performance organic thin-film transistors for practical applications in organic electronics.

  20. Thin-shell wormholes with a double layer in quadratic F (R ) gravity

    Science.gov (United States)

    Eiroa, Ernesto F.; Figueroa Aguirre, Griselda

    2016-08-01

    We present a family of spherically symmetric Lorentzian wormholes in quadratic F (R ) gravity, with a thin shell of matter corresponding to the throat. At each side of the shell, the geometry has a different constant value of the curvature scalar R . The junction conditions determine the equation of state between the pressure and energy density at the throat, where a double layer is also located. We analyze the stability of the configurations under perturbations preserving the spherical symmetry. In particular, we study thin-shell wormholes with mass and charge. We find that there exist values of the parameters for which stable static solutions are possible.

  1. n +-Microcrystalline-Silicon Tunnel Layer in Tandem Si-Based Thin Film Solar Cells

    Science.gov (United States)

    Lee, Ching-Ting; Lee, Hsin-Ying; Chen, Kuan-Hao

    2016-06-01

    In this study, the p-SiC/i-Si/n-Si cell and the p-SiC/i-SiGe/n-Si cell deposited using plasma-enhanced chemical vapor deposition were cascaded for forming the tandem Si-based thin film solar cells to absorb the wide solar spectrum. To further improve the performances of the tandem Si-based thin film solar cells, a 5-nm-thick n +-microcrystalline-Si (n +-μc-Si) tunnel layer deposited using the laser-assisted plasma-enhanced chemical vapor deposition was inserted between the p-SiC/i-Si/n-Si cell and the p-SiC/i-SiGe/n-Si cell. Since both the plasma and the CO2 laser were simultaneously utilized to efficiently decompose the reactant and doping gases, the carrier concentration and the carrier mobility of the n +-μc-Si tunnel layer were significantly improved. The ohmic contact formed between the p-SiC layer and the n +-μc-Si tunnel layer with low resistance was beneficial to the generated current transportation and the carrier recombination rate. Therefore, the conversion efficiency of the tandem solar cells was promoted from 8.57% and 8.82% to 9.91% compared to that without tunnel layer and with 5-nm-thick n +-amorphous-Si tunnel layer.

  2. n +-Microcrystalline-Silicon Tunnel Layer in Tandem Si-Based Thin Film Solar Cells

    Science.gov (United States)

    Lee, Ching-Ting; Lee, Hsin-Ying; Chen, Kuan-Hao

    2016-10-01

    In this study, the p-SiC/ i-Si/ n-Si cell and the p-SiC/ i-SiGe/ n-Si cell deposited using plasma-enhanced chemical vapor deposition were cascaded for forming the tandem Si-based thin film solar cells to absorb the wide solar spectrum. To further improve the performances of the tandem Si-based thin film solar cells, a 5-nm-thick n +-microcrystalline-Si ( n +-μc-Si) tunnel layer deposited using the laser-assisted plasma-enhanced chemical vapor deposition was inserted between the p-SiC/ i-Si/ n-Si cell and the p-SiC/ i-SiGe/ n-Si cell. Since both the plasma and the CO2 laser were simultaneously utilized to efficiently decompose the reactant and doping gases, the carrier concentration and the carrier mobility of the n +-μc-Si tunnel layer were significantly improved. The ohmic contact formed between the p-SiC layer and the n +-μc-Si tunnel layer with low resistance was beneficial to the generated current transportation and the carrier recombination rate. Therefore, the conversion efficiency of the tandem solar cells was promoted from 8.57% and 8.82% to 9.91% compared to that without tunnel layer and with 5-nm-thick n +-amorphous-Si tunnel layer.

  3. Influence of Surface Transition Layers on Phase Transformation and Pyroelectric Properties of Ferroelectric Thin Film

    Institute of Scientific and Technical Information of China (English)

    SUN Pu-Nan; L(U) Tian-Quan; CHEN Hui; CAO Wen-Wu

    2008-01-01

    Taking into account surface transition layers (STLs), we study the phase transformation and pyroelectric properties of ferroelectric thin films by employing the transverse Ising model (TIM) in the framework of the mean field approximation. The distribution functions representing the intra-layer and inter-layer couplings between the two nearest neighbour pseudo-spins are introduced to characterize STLs. Compared with the results obtained by the traditional treatments for the thin films using only the single surface transition layer (SSL), it is shown that the STL model reflects a more realistic and comprehensive situation of films. The effects of various parameters on the phase transformation properties have shown that STL can make the Curie temperature of the film higher or lower than that of the corresponding bulk material, and the thickness of STL is a key factor influencing the film properties. For a film with definite thickness, there exists a critical STL thickness at which ferroelectricity will disappear when the intra-layer and inter-layer interactions are weak.

  4. Theoretical analysis and experimental study on the influence of electric double layer on thin film lubrication

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-jie; BAI Shao-xian; HUANG Ping

    2006-01-01

    A new mathematical model for thin film lubrication is established by taking into account the effect of an electric double layer.In the present paper,experiments are carried out on a self-made tester.With a composite block and a rotating disk,influence of electric double layer on thin film lubrication is studied.Two different methods are used to reconstruct the field of electric double layer so as to change its effect.One is to change the ionic concentration of lubricants by adding additives,and the other is to apply an external electric field on friction pairs.According theoretical analysis,both the methods will apparently change the electro-viscosity of the lubricant film so as to change the lubrication performances.After theoretical calculation of electro-viscosity is amended according to the experimental results,the equations of electro-viscosity are presented.The results show that the equivalent viscosity of fluid induced by the effect of electric double layer apparently increases with the decrease of thickness of the film while the lubrication film is thin enough.The effect of electro-viscosity is weakened as the thickness of the film increases.Moreover,the effect of electro-viscosity increases with the increase of external electric field at first.When the voltage reaches a certain value,the electro-viscosity begins to decrease.

  5. High gas pressure for HTS single crystals and thin layer technology

    International Nuclear Information System (INIS)

    The properties of single crystals and thin/thick layers of high-Tc superconductors (HTS, up to 135 K) made under equilibrium (p, T) conditions of vapour and oxygen are presented. The special high gas pressure apparatus combined with a method of avoiding impurities from the outer volume of the crucible was designed and successfully applied in high pressure experiments. This apparatus was used successfully in experiments with active gases such as oxygen and nitrogen, as well as chlorides, heavy metals, sulphur, fluoride, potassium, sodium and oxides, which all produce very high partial pressure. As a result we obtained large single crystals of the mercury family of HTS compounds. The obtained single crystals and thin layers reveal a high chemical stability, which suggests their possible future application as superconducting microelectronic devices. The method presented has been successfully applied to obtain other compounds, e.g. (the HgTl-HTS family), YBCO, infinite layer and FeS2 applied for modern thin layer photovoltaic cells. (author)

  6. Indium sulfide thin films as window layer in chemically deposited solar cells

    International Nuclear Information System (INIS)

    Indium sulfide (In2S3) thin films have been synthesized by chemical bath deposition technique onto glass substrates using In(NO3)3 as indium precursor and thioacetamide as sulfur source. X-ray diffraction studies have shown that the crystalline state of the as-prepared and the annealed films is β-In2S3. Optical band gap values between 2.27 and 2.41 eV were obtained for these films. The In2S3 thin films are photosensitive with an electrical conductivity value in the range of 10−3–10−7 (Ω cm)−1, depending on the film preparation conditions. We have demonstrated that the In2S3 thin films obtained in this work are suitable candidates to be used as window layer in thin film solar cells. These films were integrated in SnO2:F/In2S3/Sb2S3/PbS/C–Ag solar cell structures, which showed an open circuit voltage of 630 mV and a short circuit current density of 0.6 mA/cm2. - Highlights: • In2S3 thin films were deposited using the Chemical Bath Deposition technique. • A direct energy band gap between 2.41 to 2.27 eV was evaluated for the In2S3 films. • We made chemically deposited solar cells using the In2S3 thin films

  7. Performance of a Polymer Flood with Shear-Thinning Fluid in Heterogeneous Layered Systems with Crossflow

    Directory of Open Access Journals (Sweden)

    Kun Sang Lee

    2011-08-01

    Full Text Available Assessment of the potential of a polymer flood for mobility control requires an accurate model on the viscosities of displacement fluids involved in the process. Because most polymers used in EOR exhibit shear-thinning behavior, the effective viscosity of a polymer solution is a highly nonlinear function of shear rate. A reservoir simulator including the model for the shear-rate dependence of viscosity was used to investigate shear-thinning effects of polymer solution on the performance of the layered reservoir in a five-spot pattern operating under polymer flood followed by waterflood. The model can be used as a quantitative tool to evaluate the comparative studies of different polymer flooding scenarios with respect to shear-rate dependence of fluids’ viscosities. Results of cumulative oil recovery and water-oil ratio are presented for parameters of shear-rate dependencies, permeability heterogeneity, and crossflow. The results of this work have proven the importance of taking non-Newtonian behavior of polymer solution into account for the successful evaluation of polymer flood processes. Horizontal and vertical permeabilities of each layer are shown to impact the predicted performance substantially. In reservoirs with a severe permeability contrast between horizontal layers, decrease in oil recovery and sudden increase in WOR are obtained by the low sweep efficiency and early water breakthrough through highly permeable layer, especially for shear-thinning fluids. An increase in the degree of crossflow resulting from sufficient vertical permeability is responsible for the enhanced sweep of the low permeability layers, which results in increased oil recovery. It was observed that a thinning fluid coefficient would increase injectivity significantly from simulations with various injection rates. A thorough understanding of polymer rheology in the reservoir and accurate numerical modeling are of fundamental importance for the exact estimation

  8. Layer-by-layer assembly of thin films containing exfoliated pristine graphene nanosheets and polyethyleneimine.

    Science.gov (United States)

    Sham, Alison Y W; Notley, Shannon M

    2014-03-11

    A method for the modification of surface properties through the deposition of stabilized graphene nanosheets is described. Here, the thickness of the film is controlled through the use of the layer-by-layer technique, where the sequential adsorption of the cationic polyethyleneimine (PEI) is followed by the adsorption of anionic graphene sheets modified with layers of polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) surfactants. The graphene particles were prepared using the surfactant-assisted liquid-phase exfoliation technique, with the low residual negative charge arising from edge defects. The buildup of the multilayer assembly through electrostatic interactions was strongly influenced by the solution conditions, including pH, ionic strength, and ionic species. Thereby, not only could the thickness of the film be tailored through the choice of the number of bilayers deposited but the viscoelastic properties of the film could also be modified by changing solution conditions at which the different species were deposited. The quartz crystal microbalance was used to measure the mass of graphene and polyelectrolyte immobilized at the interface as well as to probe the energy dissipated in the adsorbed layer.

  9. Carbon nanotube and carbon nanorod-filled polyacrylonitrile electrospun stationary phase for ultrathin layer chromatography.

    Science.gov (United States)

    Fang, Xin; Olesik, Susan V

    2014-06-01

    The application of carbon nanotube or nanorod/polyacrylonitrile (PAN) composite electrospun nanofibrous stationary phase for ultrathin layer chromatography (UTLC) is described herein. Multi-walled carbon nanotubes (MWCNTs) and edge-plane carbon (EPC) nanorods were prepared and electrospun with the PAN polymer solution to form composite nanofibers for use as a UTLC stationary phase. The analysis of laser dyes demonstrated the feasibility of utilizing carbon nanoparticle-filled electrospun nanofibers as a UTLC stationary phase. The contribution of MWCNT or EPC in changing selectivity of the stationary phase was studied by comparing the chromatographic behavior among MWCNT-PAN plates, EPC-PAN plates and pure PAN plates. Carbon nanoparticles in the stationary phase were able to establish strong π-π interactions with aromatic analytes. The separation of five polycyclic aromatic hydrocarbons (PAHs) demonstrated enhanced chromatographic performance of MWCNT-filled stationary phase by displaying substantially improved resolution and separation efficiency. Band broadening of the spots for MWCNT or EPC-filled UTLC stationary phases was also investigated and compared with that for pure PAN stationary phases. A 50% improvement in band dispersion was noted using the MWCNT based composite nanofibrous UTLC plates. PMID:24856506

  10. Axisymmetric eddy current inspection of highly conducting thin layers via asymptotic models

    Science.gov (United States)

    Haddar, Houssem; Jiang, Zixian

    2015-11-01

    Thin copper deposits covering the steam generator tubes can blind eddy current probes in non-destructive testings of problematic faults and it is therefore important that they are identified. Existing methods based on shape reconstruction using eddy current signals encounter difficulties of high numerical costs due to the layer’s small thickness and high conductivity. In this article, we approximate the axisymmetric eddy current problem with some appropriate asymptotic models using effective transmission conditions representing the thin deposits. In these models, the geometrical information related to the deposit is transformed into parameter coefficients on a fictitious interface. A standard iterative inversion algorithm is then applied to the asymptotic models to reconstruct the thickness of the thin copper layers. Numerical tests both validating the asymptotic model and showing the benefits of the inversion procedure are provided.

  11. Growth of bismuth telluride thin film on Pt by electrochemical atomic layer epitaxy

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen; YANG Jun-you; GAO Xian-hui; HOU Jie; ZHANG Tong-jun; CUI Kun

    2005-01-01

    An automated thin-layer flow cell electrodeposition system was developed for growing Bi2 Te3 thin film by ECALE. The dependence of the Bi and Te deposition potentials on Pt electrode was studied. In the first attempt,this reductive Te underpotential deposition (UPD)/reductive Bi UPD cycle was performed to 100 layers. A better linearity of the stripping charge with the number of cycles has been shown and confirmed a layer-by-layer growth mode, which is consistent with an epitaxial growth. The 4: 3 stoichiometric ratio of Bi to Te suggests that the incomplete charge transfer in HTeO2+ reduction excludes the possibility of Bi2 Te3 formation. X-ray photoelectron spectroscopy (XPS) analysis also reveals that the incomplete charge transfer in HTeO2+ occurs in Te direct deposition. The effective way of depositing Bi2 Te3 on Pt consists in oxidative Te UPD and reductive Bi UPD. The thin film deposited by this procedure was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). A polycrystalline characteristic was confirmed by XRD. The 2 : 3 stoichiometric ratio was confirmed by XPS. The SEM image indicates that the deposit looks like a series of buttons about 0.3 - 0.4 μm in diameter, which is corresponding with calculated thickness of the epitaxial film. This suggests that the particle growth appears to be linear with the number of cycles, as it is consistent with a layer by layer growth mode.

  12. Lamb waves in a thin isotropic layer between two anisotropic layers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Haiyan; ZHOU Quan; L(U) Donghui

    2004-01-01

    Attenuative Lamb wave propagation in adhesively bonded anisotropic composite plates is introduced. The isotropic adhesive exhibits viscous behavior to stimulate the poor curing of the middle layer. Viscosity is assumed to vary linearly with frequency, implying that attenuation per wavelength is constant. Attenuation can be implemented in the analysis through modification of elastic properties of isotropic adhesive. The new properties become complex, but cause no further complications in the analysis. The characteristic equation is the same as that used for the elastic plate case, except that both real and imaginary parts of the wave number (i.e., the attenuation) must be computed. Based on the Lowe's solution in finding the complex roots of characteristic equation, the effect of longitudinal and shear attenuation coefficients of the middle adhesive layer on phase velocity dispersion curves and attenuation dispersion curves of Lamb waves propagating in bonded anisotropic composites is visualized numerically.

  13. Highly (100) oriented MgO growth on thin Mg layer in MTJ structure

    Science.gov (United States)

    Jimbo, K.; Nakagawa, S.

    2011-01-01

    In order to apply Stress Assisted Magnetization Reversal (SAMR) method to perpendicular magnetoresistive random access memory (p-MRAM) with magnetic tunnel junction (MTJ) using MgO (001) oriented barrier layer, multilayer of Ta/ Terfenol-D/ Mg/ MgO and Ta/ Terfenol-D/ MgO were prepared. While the MgO layer, deposited directly on the Terfenol-D layer, did not show (100) orientatin, very thin metallic Mg layer, deposited prior to the MgO deposition, was effective to attain MgO (100) orientation. The crystalline orientation was very weak without Mg, however, the multilayer with Mg showed very strong MgO(100) peak and the MgO orientation was shifted depending on the Mg thickness.

  14. Thermally activated decomposition of (Ga,Mn)As thin layer at medium temperature post growth annealing

    Science.gov (United States)

    Melikhov, Y.; Konstantynov, P.; Domagala, J.; Sadowski, J.; Chernyshova, M.; Wojciechowski, T.; Syryanyy, Y.; Demchenko, I. N.

    2016-05-01

    The redistribution of Mn atoms in Ga1-xMnxAs layer during medium-temperature annealing, 250-450 oC, by Mn K-edge X-ray absorption fine structure (XAFS) recorded at ALBA facility, was studied. For this purpose Ga1-xMnxAs thin layer with x=0.01 was grown on AlAs buffer layer deposited on GaAs(100) substrate by molecular beam epitaxy (MBE) followed by annealing. The examined layer was detached from the substrate using a “lift-off” procedure in order to eliminate elastic scattering in XAFS spectra. Fourier transform analysis of experimentally obtained EXAFS spectra allowed to propose a model which describes a redistribution/diffusion of Mn atoms in the host matrix. Theoretical XANES spectra, simulated using multiple scattering formalism (FEFF code) with the support of density functional theory (WIEN2k code), qualitatively describe the features observed in the experimental fine structure.

  15. Influence of adhesive layer properties on laser-generated ultrasonic waves in thin bonded plates

    Institute of Scientific and Technical Information of China (English)

    Sun Hong-Xiang; Xu Bai-Qiang; Zhang Hua; Gao Qian; Zhang Shu-Yi

    2011-01-01

    This paper studies quantitatively the generation of Lamb waves in thin bonded plates subjected to laser illumination, after considering the viscoelasticity of the adhesive layer. The displacements of such plates have been calculated in the frequency domain by using the finite element method, and the time domain response has been reconstructed by applying an inverse fast Fourier transform. Numerical results are presented showing the normal surface displacement for several configurations: a single aluminum plate, a three-layer bonded plate, and a two-layer plate. The characteristics of the laser-generated Lamb waves for each particular case have been investigated. In addition, the sensitivity of the transient responses to variations of material properties (elastic modulus, viscoelastic modulus, and thickness) of the adhesive layer has been studied in detail.

  16. Laser generated guided waves and finite element modeling for the thickness gauging of thin layers

    International Nuclear Information System (INIS)

    In this paper, nondestructive testing has been performed on a thin gold layer deposited on a 2 in. silicon wafer. Guided waves were generated and studied using a laser ultrasonic setup and a two-dimensional fast Fourier transform technique was employed to obtain the dispersion curves. A gold layer thickness of 1.33 μm has been determined with a ±5% margin of error using the shape of the two first propagating modes, assuming for the substrate and the layer an uncertainty on the elastic parameters of ±2.5%. A finite element model has been implemented to validate the data post-treatment and the experimental results. A good agreement between the numerical simulation, the analytical modeling and the experimentations has been observed. This method was considered suitable for thickness layer higher than 0.7 μm.

  17. Analysis of the p+/p window layer of thin film solar cells by simulation

    Institute of Scientific and Technical Information of China (English)

    林爱国; 丁建宁; 袁宁一; 王书博; 程广贵; 卢超

    2012-01-01

    The application of a p+/p configuration in the window layer of hydrogenated amorphous silicon thin film solar cells is simulated and analyzed utilizing an AMPS-1D program.The differences between p+-p-i-n configuration solar cells and p-i-n configuration solar cells are pointed out.The effects of dopant concentration,thickness of p+-layer,contact barrier height and defect density on solar cells are analyzed.Our results indicate that solar cells with a p+-p-i-n configuration have a better performance.The open circuit voltage and short circuit current were improved by increasing the dopant concentration of the p+ layer and lowering the front contact barrier height.The defect density at the p/i interface which exceeds two orders of magnitude in the intrinsic layer will deteriorate the cell property.

  18. Thin catalyst layers based on carbon nanotubes for PEM-fuel cell applications

    Science.gov (United States)

    Bohnenberger, T.; Matovic, J.; Schmid, U.

    2011-06-01

    In this study, two approaches are compared to develop thin, multifunctional films of carbon nanotubes (CNT) which are targeted to serve as a catalyst layer in fuel cells. The first is based on the direct deposition of mixed multi- and single-wall CNTs on metalized silicon wafers, using the metallization as a sacrificial layer to subsequently detach the CNT film from the substrate. It is a less time consuming and a straight forward method compared to the alternative under investigation, the layer-by-layer technique (LbL). The LbL uses bilayers of charged nanotubes to slowly build up a film with an exactly defined thickness. The process is well controlled, but the time constants for deposition of each bilayer are rather high (i.e. about 1 h). With additional annealing steps implemented during film generation this method, however, is regarded advantageous as membranes results with improved mechanical stability and a good homogeneity.

  19. Analysis of the p+/p window layer of thin film solar cells by simulation

    International Nuclear Information System (INIS)

    The application of a p+/p configuration in the window layer of hydrogenated amorphous silicon thin film solar cells is simulated and analyzed utilizing an AMPS-1D program. The differences between p+−p—i—n configuration solar cells and p—i—n configuration solar cells are pointed out. The effects of dopant concentration, thickness of p+-layer, contact barrier height and defect density on solar cells are analyzed. Our results indicate that solar cells with a p+−p—i—n configuration have a better performance. The open circuit voltage and short circuit current were improved by increasing the dopant concentration of the p+ layer and lowering the front contact barrier height. The defect density at the p/i interface which exceeds two orders of magnitude in the intrinsic layer will deteriorate the cell property. (semiconductor materials)

  20. Successful implementation of the stepwise layer-by-layer growth of MOF thin films on confined surfaces: Mesoporous silica foam as a first case study

    KAUST Repository

    Shekhah, Osama

    2012-01-01

    Here we report the successful growth of highly crystalline homogeneous MOF thin films of HKUST-1 and ZIF-8 on mesoporous silica foam, by employing a layer-by-layer (LBL) method. The ability to control and direct the growth of MOF thin films on confined surfaces, using the stepwise LBL method, paves the way for new prospective applications of such hybrid systems. © 2012 The Royal Society of Chemistry.

  1. Ultra-thin resistive switching oxide layers self-assembled by field-induced oxygen migration (FIOM) technique.

    Science.gov (United States)

    Lee, Sangik; Hwang, Inrok; Oh, Sungtaek; Hong, Sahwan; Kim, Yeonsoo; Nam, Yoonseung; Lee, Keundong; Yoon, Chansoo; Kim, Wondong; Park, Bae Ho

    2014-11-03

    High-performance ultra-thin oxide layers are required for various next-generation electronic and optical devices. In particular, ultra-thin resistive switching (RS) oxide layers are expected to become fundamental building blocks of three-dimensional high-density non-volatile memory devices. Until now, special deposition techniques have been introduced for realization of high-quality ultra-thin oxide layers. Here, we report that ultra-thin oxide layers with reliable RS behavior can be self-assembled by field-induced oxygen migration (FIOM) at the interface of an oxide-conductor/oxide-insulator or oxide-conductor/metal. The formation via FIOM of an ultra-thin oxide layer with a thickness of approximately 2-5 nm and 2.5% excess oxygen content is demonstrated using cross-sectional transmission electron microscopy and secondary ion mass spectroscopy depth profile. The observed RS behavior, such as the polarity dependent forming process, can be attributed to the formation of an ultra-thin oxide layer. In general, as oxygen ions are mobile in many oxide-conductors, FIOM can be used for the formation of ultra-thin oxide layers with desired properties at the interfaces or surfaces of oxide-conductors in high-performance oxide-based devices.

  2. STUDY ON THE DETERMINATION OF TRACE Fe(Ⅲ) BY THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A method to determine Fe(Ⅲ) by thin layer resin phase spectrophotometry has been developed in this paper. The colored complex formed by Fe(Ⅲ) and 1,2-benzendiol is concentrated on the 717# resin, then Fe(Ⅲ) can be determined directly by making thin layer. The method is sensitive with a apparent molar absorption of 4.8×104L/mol·cm, which is 16 times higher than that of liquid phase spectrophotometry, most coexisting ions do not influence the determination. The detection limit for Fe(Ⅲ) is 1.47μg/L with the precision of 3.3% [n=6, 7μg/50mL Fe(Ⅲ)]. The calibration curve is linear in the range of 0~25μg/50mL. The preposed method was applied to the determination of Fe(Ⅲ) in water sample with satisfactory results.

  3. Influence of electric double layer on thin film lubrication and elastohydrodynamic lubrication

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In the present paper, the influence of electric double layer (EDL) on thin film lubricationand elastohydrodynamic lubrication is studied. With modified Reynolds equation for electric doublelayer, the effect of zeta-potential on the film thickness and pressure is numerically calculated. Theresults show that the influence of electric double layer on the lubrication film thickness is significantonly for thin film. The minimum film thickness will increase greatly if the influence of EDL is con-sidered. As the initial film thickness increases, the effect will greatly decrease. The existence ofEDL will decrease the friction coefficient of the lubrication film. Furthermore, the above tendency isstill applicable even if the materials of the friction pair are different.

  4. Mathematical modelling of the thin layer solar drying of banana, mango and cassava

    Energy Technology Data Exchange (ETDEWEB)

    Koua, Kamenan Blaise; Fassinou, Wanignon Ferdinand; Toure, Siaka [Laboratoire d' Energie Solaire, Universite de Cocody- Abidjan, 22 BP 582 Abidjan 22 (Ivory Coast); Gbaha, Prosper [Laboratoire d' Energie Nouvelle et Renouvelable, Institut National Polytechnique, Felix HOUPHOUET - BOIGNY de Yamoussoukro (Ivory Coast)

    2009-10-15

    The main objectives of this paper are firstly to investigate the behaviour of the thin layer drying of plantain banana, mango and cassava experimentally in a direct solar dryer and secondly to perform mathematical modelling by using thin layer drying models encountered in literature. The variation of the moisture content of the products studied and principal drying parameters are analysed. Seven statistical models, which are empirical or semi-empirical, are tested to validate the experimental data. A non-linear regression analysis using a statistical computer program is used to evaluate the constants of the models. The Henderson and Pabis drying model is found to be the most suitable for describing the solar drying curves of plantain banana, mango and cassava. The drying data of these products have been analysed to obtain the values of the effective diffusivity during the falling drying rate phase. (author)

  5. STUDY ON THE DETERMINATION OF TRACE Fe(Ⅲ) BY THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

    Institute of Scientific and Technical Information of China (English)

    HOU Yanmin; YANG Yongsheng; XIE Jimin; HUANG Weihong

    2007-01-01

    A method to determine Fe(Ⅲ) by thin layer resin phase spectrophotometry has been developed in this paper. The colored complex formed by Fe(Ⅲ) and 1,2-benzendiol is concentrated on the 717# resin, then Fe(Ⅲ) can be determined directly by making thin layer. The method is sensitive with a apparent molar absorption of 4.8×104L/mol. cm, which is 16 times higher than that of liquid phase spectrophotometry, most coexisting ions do not influence the determination. The detection limit for Fe(Ⅲ) is 1.47μg/L with the precision of 3.3% [n=6, 7μg/50mL Fe(Ⅲ)]. The calibration curve is linear in the range of 0~25μg/50mL. The preposed method was applied to the determination of Fe(Ⅲ) in water sample with satisfactory results.

  6. Determination Of Refractive Index And Reflectivity Of Thin Layer With Optical Absorption Method

    International Nuclear Information System (INIS)

    . The refractive index and reflectivity of ASi:H and Si Ox thin layer have been observed by optical absorption methods. Measurement has been done after the preparation of optical system which consists of a halogen lamp light source, monochromator, sample and light detector. The Monochromator output showed that measured halogen lamp spectrum light is between 470 nm -750 nm. The maximum voltage of halogen lamp is 220 Volt, the output light increases in intensity while the wave length increases. The inclination of intensity decrease at the wave length of 725 nm. The result of the calculation of refractive index varies in accordance with the wave length. The average refractive index of ASi:H is nf a = 1.753. The total reflectivity of air-thin layer-substrate is Rt a = 0.315. The refractive index of Si Ox sample is nf b2.182 and the total reflectivity is Rt b=O,514

  7. Diffusion barrier properties of atomic-layer-deposited iridium thin films on Cu/Ir/Si structures

    International Nuclear Information System (INIS)

    We investigated the diffusion barrier properties of an atomic-layer-deposited 12-nm-thick iridium (Ir) thin film as functions of the thermal treatment temperature. Up to a temperature of 500 .deg. C, the Ir thin film maintained its initial configuration, preventing the penetration of the Cu layer into Si through the Ir layer. The thermal stability of the Ir layer up to 500 .deg. C was confirmed by using high resolution transmission electron microscopy, Auger electron microscopy, and X-ray diffraction. In contrast, when the Ir layer was thermally annealed at 600 .deg. C, copper silicide was formed, and interdiffusion of Cu and Ir was observed.

  8. PECULIARITIES OF LAMB WAVE PROPAGATION THROUGH TWO-LAYERED THIN PLATE MATERIALS

    Directory of Open Access Journals (Sweden)

    A. R. Baev

    2008-01-01

    Full Text Available Peculiarities of the plate wave propagation through two-layered thin plate have been analyzed and formulas for velocity determination of the quickest plate mode have been proposed.  The ascertained interaction makes it possible   to determine coating layer thickness in accordance with the given and known elastic parameters of contacting materials. On the basis of the developed methodology experiments have been carried out that revealed qualitative and quantitative correspondence  between theoretical and experimental data. The paper shows a principle possibility for assessment  of  material separation surface by time propagation data of the investigated mode .

  9. Thickness gauging of thin layers by laser ultrasonics and neural network

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, F; Jenot, F; Ouaftouh, M; Duquennoy, M; Ourak, M, E-mail: Fabien.lefevre@univ-valenciennes.fr [Institut d' Electronique de Microelectronique et de Nanotechnologie Departement Opto-Acousto-Electronique (UMR CNRS 8520), Universite de Valenciennes, Le Mont Houy, 59313 Valenciennes Cedex 09 (France)

    2011-01-01

    Non destructive testing has been performed on a thin indium layer deposited on a two inches silicon wafer. Guided waves were generated and studied using a laser ultrasonic setup, and a two-dimensional Fourier transform technique was employed to obtain the dispersion curves. The inverse problem, in other words the determination of the layer thickness and the elastic constants of the substrate, has been solved by means of a feedforward neural network. These parameters were then evaluated simultaneously, the dispersion curves being entirely fitted. The experimental results show a good agreement with the theoretical model. This inversion method was found to be prompt and easy to automate.

  10. Ferroelectric control of magnetic domains in ultra-thin cobalt layers

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.; Stolichnov, I.; Setter, N. [Ceramics Laboratory, EPFL-Swiss Federal Institute of Technology, Lausanne 1015 (Switzerland); Bernand-Mantel, A.; Borrel, J.; Pizzini, S.; Ranno, L.; Herrera Diez, L. [University of Grenoble Alpes, Institut Néel, F-38042 Grenoble (France); CNRS, Institut Néel, F-38042 Grenoble (France); Auffret, S.; Gaudin, G.; Boulle, O. [SPINTEC, UMR-8191, CEA/CNRS/UJF/GINP, INAC, F-38054 Grenoble (France)

    2013-11-25

    Non-volatile ferroelectric control of magnetic domains has been demonstrated in ultra-thin cobalt layers at room temperature. The sensitivity of magnetic anisotropy energy to the electronic structure in a few atomic layers adjacent to the interface allows for ferroelectric control of coercivity and magnetic domain dynamics. These effects have been monitored and quantified using magneto-optical Kerr effect. In particular, the regimes, where the ferroelectric domains enhance/inhibit the magnetic domain nucleation or increase/reduce domain wall velocity, have been explored. Thus, non-destructive and reversible ferroelectric domain writing provides a tool to define the magnetic domain paths, create nucleation sites, or control domain movement.

  11. Thickness gauging of thin layers by laser ultrasonics and neural network

    International Nuclear Information System (INIS)

    Non destructive testing has been performed on a thin indium layer deposited on a two inches silicon wafer. Guided waves were generated and studied using a laser ultrasonic setup, and a two-dimensional Fourier transform technique was employed to obtain the dispersion curves. The inverse problem, in other words the determination of the layer thickness and the elastic constants of the substrate, has been solved by means of a feedforward neural network. These parameters were then evaluated simultaneously, the dispersion curves being entirely fitted. The experimental results show a good agreement with the theoretical model. This inversion method was found to be prompt and easy to automate.

  12. Reduced Cu concentration in CuAl-LPE-grown thin Si layers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.H.; Ciszek, T.F.; Asher, S.; Reedy, R. [National Renewable Energy Lab., Golden, CO (United States)

    1995-08-01

    Cu-Al has been found to be a good solvent system to grow macroscopically smooth Si layers with thicknesses in tens of microns on cast MG-Si substrates by liquid phase epitaxy (LPE) at temperatures near 900{degrees}C. This solvent system utilizes Al to ensure good wetting between the solution and substrate by removing silicon native oxides, and employs Cu to control Al doping into the layers. Isotropic growth is achieved because of a high concentration of solute silicon in the solution and the resulting microscopically rough interface. The incorporation of Cu in the Si layers, however, was a concern since Cu is a major solution component and is generally regarded as a bad impurity for silicon devices due to its fast diffusivity and deep energy levels in the band gap. A study by Davis shows that Cu will nonetheless not degrade solar cell performance until above a level of 10{sup 17} cm{sup -3}. This threshold is expected to be even higher for thin layer silicon solar cells owing to the less stringent requirement on minority carrier diffusion length. But to ensure long term stability of solar cells, lower Cu concentrations in the thin layers are still preferred.

  13. Biophotonic low-coherence sensors with boron-doped diamond thin layer

    Science.gov (United States)

    Milewska, D.; Karpienko, K.; Sobaszek, M.; Jedrzejewska-Szczerska, M.

    2016-03-01

    Low-coherence sensors using Fabry-Perot interferometers are finding new applications in biophotonic sensing, especially due to the rapid technological advances in the development of new materials. In this paper we discuss the possibility of using boron-doped nanodiamond layers to protect mirror in a Fabry-Perot interferometer. A low-coherence sensor using Fabry-Perot interferometer with a boron-doped nanodiamond (B-NCD) thin protective layer has been developed. B-NCD layers with different boron doping level were investigated. The boron level, expressed as the boron to carbon (/[C]) ratio in the gas phase, was: 0, 2000, 5000 or 10000 ppm. B-NCD layers were grown by chemical vapor deposition (CVD). The sensing Fabry-Perot interferometer, working in the reflective mode, was connected to the source and to the optical processor by single-mode fibers. Superluminescent diodes with Gaussian spectral density were used as sources, while an optical spectrum analyzer was used as an optical processor. The design of the sensing interferometer was optimized to attain the maximum interference contrast. The experiment has shown that B-NCD thin layers can be successfully used in biophotonic sensors.

  14. Picosecond laser structuring of thin film platinum layers covered with tantalum pentoxide isolation

    Energy Technology Data Exchange (ETDEWEB)

    Heise, Gerhard; Huber, Heinz [Lasercenter, Munich University of Applied Sciences, Lothstr. 34, D-80335 Muenchen (Germany); Trappendreher, Daniel [Heinz-Nixdorf-Chair for Medical Electronics, Technische Universitaet Muenchen, Theresienstrasse 90, D-80333 Muenchen (Germany); Lasercenter, Munich University of Applied Sciences, Lothstr. 34, D-80335 Muenchen (Germany); Ilchmann, Florian; Weiss, Robin S.; Wolf, Bernhard [Heinz-Nixdorf-Chair for Medical Electronics, Technische Universitaet Muenchen, Theresienstrasse 90, D-80333 Muenchen (Germany)

    2012-07-01

    A thin film layer system consisting of platinum (Pt) as conductive layer on a glass substrate and tantalum pentoxide as isolating layer on top of the platinum is attractive for designing biocompatible conductor paths and contact pads for bio sensor chips. For the flexible and rapid patterning of the conductive and the isolating layers, both, the complete removal and the selective ablation of the individual thin films were investigated using ultra-short laser pulses with about 10 ps pulse duration and 1064 nm wavelength at low laser fluences. A platinum film covered with tantalum pentoxide shows a significantly lower ablation threshold than a single Pt film on glass alone when illuminated from the front side. Furthermore, we explored that the tantalum pentoxide film can be removed by glass side illumination from the Pt film, without affecting the Pt film and leaving the Pt film on the glass substrate intact. Those ablation phenomena occur at laser fluences of about 0.2 J/cm{sup 2}, far below the evaporation limit of platinum. We present a detailed ablation threshold value examination for the structuring of these layer systems by front side and glass side irradiation for different film thicknesses. Furthermore, we discuss the possible underlying physical mechanisms of these ablation phenomena.

  15. Picosecond laser structuring of thin film platinum layers covered with tantalum pentoxide isolation

    International Nuclear Information System (INIS)

    A thin film layer system consisting of platinum (Pt) as conductive layer on a glass substrate and tantalum pentoxide as isolating layer on top of the platinum is attractive for designing biocompatible conductor paths and contact pads for bio sensor chips. For the flexible and rapid patterning of the conductive and the isolating layers, both, the complete removal and the selective ablation of the individual thin films were investigated using ultra-short laser pulses with about 10 ps pulse duration and 1064 nm wavelength at low laser fluences. A platinum film covered with tantalum pentoxide shows a significantly lower ablation threshold than a single Pt film on glass alone when illuminated from the front side. Furthermore, we explored that the tantalum pentoxide film can be removed by glass side illumination from the Pt film, without affecting the Pt film and leaving the Pt film on the glass substrate intact. Those ablation phenomena occur at laser fluences of about 0.2 J/cm2, far below the evaporation limit of platinum. We present a detailed ablation threshold value examination for the structuring of these layer systems by front side and glass side irradiation for different film thicknesses. Furthermore, we discuss the possible underlying physical mechanisms of these ablation phenomena.

  16. Deposition of metal chalcogenide thin films by successive ionic layer adsorption and reaction (SILAR) method

    Indian Academy of Sciences (India)

    H M Pathan; C D Lokhande

    2004-04-01

    During last three decades, successive ionic layer adsorption and reaction (SILAR) method, has emerged as one of the solution methods to deposit a variety of compound materials in thin film form. The SILAR method is inexpensive, simple and convenient for large area deposition. A variety of substrates such as insulators, semiconductors, metals and temperature sensitive substrates (like polyester) can be used since the deposition is carried out at or near to room temperature. As a low temperature process, it also avoids oxidation and corrosion of the substrate. The prime requisite for obtaining good quality thin film is the optimization of preparative provisos viz. concentration of the precursors, nature of complexing agent, pH of the precursor solutions and adsorption, reaction and rinsing time durations etc. In the present review article, we have described in detail, successive ionic layer adsorption and reaction (SILAR) method of metal chalcogenide thin films. An extensive survey of thin film materials prepared during past years is made to demonstrate the versatility of SILAR method. Their preparative parameters and structural, optical, electrical properties etc are described. Theoretical background necessary for the SILAR method is also discussed.

  17. Atomically thin layered NiFe double hydroxides assembled 3D microspheres with promoted electrochemical performances

    Science.gov (United States)

    Li, Xiaomin; Zai, Jiantao; Liu, Yuanyuan; He, Xiaobo; Xiang, Shijie; Ma, Zifeng; Qian, Xuefeng

    2016-09-01

    LDHs in atomic thickness (mono-/bi-layers) usually exhibit novel physicochemical properties, especially in surface-dependent energy storage and catalysis areas. However, the thickness of the commonly reported 2D LDHs is in nanoscale and the bottom-up synthesis of atomically thin LDHs is rarely reported. Herein, high-quality atomically thin layered NiFe-LDHs assembled 3D microspheres were synthesized via a rational designed reaction system, where the formation of atomically thin building blocks was controlled by the synergetic effects of released carbonate anions and butanol. Furthermore, the complexant and solvents played important effects on the process of coprecipitation and the assembling of LDHs. Due to the nature of atomically thin LDHs nanosheets and unique 3D hierarchical structures, the obtained microspheres exhibited excellent electrocatalytic oxygen evolution reaction (OER) activity in alkaline medium with an onset overpotential (0.435 V, which is lower than that of common LDHs) and good durability. The as-prepared 3D NiFe-LDHs microspheres were also firstly used as supercapacitor materials and displayed a high specific capacitance of 1061 F g-1 at the current density of 1 A g-1.

  18. Retention of heavy metals on layered double hydroxides thin films deposited by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Vlad, A., E-mail: angela.vlad@gmail.com [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 76900 Bucharest-Magurele (Romania); Birjega, R.; Matei, A.; Luculescu, C.; Mitu, B.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 76900 Bucharest-Magurele (Romania); Zavoianu, R.; Pavel, O.D. [University of Bucharest, Faculty of Chemistry, Department of Chemical Technology and Catalysis, 4-12 Regina Elisabeta Bd., Bucharest (Romania)

    2014-05-01

    Heavy metals are toxic and hazardous pollutants in the environment due to their nonbiodegradability and persistence, which can pose serious threats to living organisms. The ability of Mg–Al based layered double hydroxides (LDHs) thin films to retain heavy metals from aqueous solutions at different concentrations is a novel topic with prospects of attractive applications, such as detection of heavy metals. We report on the ability of a series of Mg–Al based layered double hydroxides thin films to detect Ni and Co cations in aqueous solutions. Uptake of heavy metals ions such as Ni{sup 2+}, Co{sup 2+} from aqueous solutions was studied as function of contact time at a standard metal ion concentration. The LDHs thin films were deposited using pulsed laser deposition (PLD). The different adsorption mechanisms were studied in connection with different heavy metals used as probe cations. X-ray diffraction, atomic force microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, Fourier transform infra-red spectroscopy were the techniques used for the investigation of as deposited and after heavy metals retention thin films.

  19. Low-temperature atomic layer deposition of TiO2 thin layers for the processing of memristive devices

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) represents one of the most fundamental techniques capable of satisfying the strict technological requirements imposed by the rapidly evolving electronic components industry. The actual scaling trend is rapidly leading to the fabrication of nanoscaled devices able to overcome limits of the present microelectronic technology, of which the memristor is one of the principal candidates. Since their development in 2008, TiO2 thin film memristors have been identified as the future technology for resistive random access memories because of their numerous advantages in producing dense, low power-consuming, three-dimensional memory stacks. The typical features of ALD, such as self-limiting and conformal deposition without line-of-sight requirements, are strong assets for fabricating these nanosized devices. This work focuses on the realization of memristors based on low-temperature ALD TiO2 thin films. In this process, the oxide layer was directly grown on a polymeric photoresist, thus simplifying the fabrication procedure with a direct liftoff patterning instead of a complex dry etching process. The TiO2 thin films deposited in a temperature range of 120–230 °C were characterized via Raman spectroscopy and x-ray photoelectron spectroscopy, and electrical current–voltage measurements taken in voltage sweep mode were employed to confirm the existence of resistive switching behaviors typical of memristors. These measurements showed that these low-temperature devices exhibit an ON/OFF ratio comparable to that of a high-temperature memristor, thus exhibiting similar performances with respect to memory applications

  20. Low-temperature atomic layer deposition of TiO{sub 2} thin layers for the processing of memristive devices

    Energy Technology Data Exchange (ETDEWEB)

    Porro, Samuele, E-mail: samuele.porro@polito.it; Conti, Daniele; Guastella, Salvatore; Ricciardi, Carlo [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Jasmin, Alladin; Pirri, Candido F. [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy and Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, C.so Trento 21, 10129 Torino (Italy); Bejtka, Katarzyna; Perrone, Denis; Chiolerio, Alessandro [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, C.so Trento 21, 10129 Torino (Italy)

    2016-01-15

    Atomic layer deposition (ALD) represents one of the most fundamental techniques capable of satisfying the strict technological requirements imposed by the rapidly evolving electronic components industry. The actual scaling trend is rapidly leading to the fabrication of nanoscaled devices able to overcome limits of the present microelectronic technology, of which the memristor is one of the principal candidates. Since their development in 2008, TiO{sub 2} thin film memristors have been identified as the future technology for resistive random access memories because of their numerous advantages in producing dense, low power-consuming, three-dimensional memory stacks. The typical features of ALD, such as self-limiting and conformal deposition without line-of-sight requirements, are strong assets for fabricating these nanosized devices. This work focuses on the realization of memristors based on low-temperature ALD TiO{sub 2} thin films. In this process, the oxide layer was directly grown on a polymeric photoresist, thus simplifying the fabrication procedure with a direct liftoff patterning instead of a complex dry etching process. The TiO{sub 2} thin films deposited in a temperature range of 120–230 °C were characterized via Raman spectroscopy and x-ray photoelectron spectroscopy, and electrical current–voltage measurements taken in voltage sweep mode were employed to confirm the existence of resistive switching behaviors typical of memristors. These measurements showed that these low-temperature devices exhibit an ON/OFF ratio comparable to that of a high-temperature memristor, thus exhibiting similar performances with respect to memory applications.

  1. Thin layer drying model for gas-fired infrared drying of paddy

    OpenAIRE

    Juckamas Laohavanich; Seree Wongpichet

    2008-01-01

    Wet Paddy (KDML 105 variety) was dried under different process conditions applying a pilot scale experimental gas-fired infrared dryer. The infrared radiation is expressed in terms of peak wavelength of infrared emitter, and the initialmoisture content of paddy were varied to study the drying behavior. Five existing mathematical models describing thin layer drying have been investigated. The experimental results were compared considering their goodness of fit in terms of coefficientof determi...

  2. Electrochemical investigations on crevice corrosion of a martensitic stainless steel in a thin-layer cell

    OpenAIRE

    Marcelin, Sabrina; Pébère, Nadine; Régnier, Sophie

    2015-01-01

    International audience; This paper focuses on crevice corrosion resistance of a martensitic stainless steel. First, electrochemical measurements were performed in deaerated bulk electrolytes for different chloride concentrations and different values of the pH to determine the critical parameters leading to dissolution or breakdown of the passive film. Then, a thin-layer cell was designed to confine the electrolyte between two parallel stainless steel planes. Impedance measurements obtained fo...

  3. Deposition and optimization of thin lead layers for superconducting accelerator photocathodes

    CERN Document Server

    Lorkiewicz, J; Barlak, M; Mirowski, R; Bartnik, A; Kostecki, J; Sekutowicz, J; Malinowska, A; Kneisel, P; Witkowski, J

    2014-01-01

    A combination of a ultra high vacuum arc deposition system and a recrystallization method was used to optimize the smoothness and thickness of thin-layer lead cathodes for superconducting niobium electron injectors. A non-filtered arc system was chosen to deposit Pb films on niobium. The films then underwent melting and recrystallization by treating them with pulsed argon ion beams in a rod plasma injector.

  4. Laser ultrasonics and guided waves for the thickness estimation of thin layers

    OpenAIRE

    Lefèvre, Fabien; Jenot, Frédéric; Ouaftouh, Mohammadi; Duquennoy, Marc; Ourak, Mohamed

    2010-01-01

    The dispersion of guided waves has been probed to estimate the thickness of a thin gold layer deposited on a two inches silicon wafer. Ultrasonic waves were generated and detected in a non-destructive and non-contact way using a laser ultrasonic setup. The guided waves dispersion curves were experimentally obtained with a two-dimensional Fourier transform, revealing the propagation of several modes. The development and the study of an analytical model allowed the determination of the most sen...

  5. Imaging ultra thin layers with helium ion microscopy: Utilizing the channeling contrast mechanism

    Directory of Open Access Journals (Sweden)

    Gregor Hlawacek

    2012-07-01

    Full Text Available Background: Helium ion microscopy is a new high-performance alternative to classical scanning electron microscopy. It provides superior resolution and high surface sensitivity by using secondary electrons.Results: We report on a new contrast mechanism that extends the high surface sensitivity that is usually achieved in secondary electron images, to backscattered helium images. We demonstrate how thin organic and inorganic layers as well as self-assembled monolayers can be visualized on heavier element substrates by changes in the backscatter yield. Thin layers of light elements on heavy substrates should have a negligible direct influence on backscatter yields. However, using simple geometric calculations of the opaque crystal fraction, the contrast that is observed in the images can be interpreted in terms of changes in the channeling probability.Conclusion: The suppression of ion channeling into crystalline matter by adsorbed thin films provides a new contrast mechanism for HIM. This dechanneling contrast is particularly well suited for the visualization of ultrathin layers of light elements on heavier substrates. Our results also highlight the importance of proper vacuum conditions for channeling-based experimental methods.

  6. Mathematical Model on Thin Layer Drying of Finger Millet (Eluesine coracana

    Directory of Open Access Journals (Sweden)

    G.B. Radhika

    2011-04-01

    Full Text Available Thin layer drying characteristics of the finger millet (Eluesine coracana samples with an Initial Moisture Content (IMC of 38.5%, on dry basis (db were studied. The drying experiments were carried out in a conventional tray dryer at temperatures of 50, 70 and 80ºC. The drying data were fitted to nine thin layer models and a thin layer model for the finger millet was developed by regressing the coefficients of the best fit. The logarithmic model was found to satisfactorily describe the drying kinetics of the millet. The drying constants were found to vary linearly with temperature. Also, effective diffusivity was evaluated by using Fick’s law, which varied from 1.526x10-10 to 2.85x10-10 m2/s. Temperature dependence of diffusivity was found by Arrhenius type of relationship and the activation energy for the diffusion of the moisture associated with the millet was found to be 35.37 kJ/gmol.

  7. Thin layered drawing media probed by THz time-domain spectroscopy

    CERN Document Server

    Tasseva, J; Bartolini, P; Striova, J; Fontana, R; Torre, R

    2016-01-01

    Dry and wet drawing materials were investigated by THz time-domain spectroscopy in transmission mode. Carbon-based and iron-gall inks have been studied, some prepared following ancient recipes and others using current synthetic materials; a commercial ink was studied as well. We measured the THz signals on thin film of liquid inks deposited on polyethylene pellicles, comparing the results with the thick pellets of dried inks blended with polyethylene powder. This study required the implementation of a new experimental method and data analysis procedure able to provide a reliable extraction of the material transmission parameters from a structured sample composed of thin layers, down to thickness of few tens of micrometers. THz measurements on thin ink layers enabled the determination of both the absorption and the refractive index in an absolute scale in the 0.1 - 3 THz range, as well as the layer thickness. THz spectroscopic features of a paper sheet dyed by one of the iron-gall inks were also investigated. ...

  8. Time-Domain reflection field analysis for evaluation of thin layered medium

    International Nuclear Information System (INIS)

    In the conventional ultrasonic testing of a thin layer with the thickness less than wavelength, successive echo signals become inseparable and to 'see' directly the time interval between them become impossible. Also, frequency domain techniques such as frequency spectroscopy is not applicable in high frequency region beyond about twice of frequency band width of a ultrasonic transducer. Recently, a new time-domain analysis technique to determine the thickness(or the wave velocity) of a thin plate and through-transmission experiments were reported. We have studied to know the validity of the technique and applicability to contact testing under a reflection system which is easier to access and more generally used. We drived a reconstructed reflection field equation. We performed experiments in reflection field system using contact type transducers of center frequency 1, 2.25, and 5 MHz with water layers of thickness ranging from 0.055 mm to 1.44 mm(0.037) larger than about 0.4, 3% for h*/λ larger than 0.8, and 1% for h*/λ larger than 2. High frequency elastic wave was effective for more accurate measurement of thickness or wave velocity in our reflection system. The time domain technique was applicable to evaluation of a thin layered medium under reflection system using contact type transducers.

  9. Molecular Orientation of Hydroquinone Adsorbed at a Platinum(111) Thin-Layer Electrode.

    Science.gov (United States)

    Ren; Hubbard

    1999-01-15

    Reported are new findings regarding the molecular orientation of hydroquinone (HQ) adsorbed on Pt surfaces. The packing density of hydroquinone adsorbed from 1 M HClO4 supporting electrolyte has been measured by use of a Pt(111) thin-layer electrode. The packing-density-vs-concentration profiles for hydroquinone, measured by a differential thin-layer electrode method at an ordered Pt(111) surface and at an electrochemically disordered Pt(111) surface, are identical within an experimental error of about 8%. The profiles from this study are similar to the ones obtained previously at an ordered Pt(111) surface by Auger spectroscopy, but they are significantly different from those reported previously for polycrystalline Pt thin-layer electrodes. A procedure based upon displacement of HQ by thiocyanate has been developed as an alternative method for determining the packing density of adsorbed HQ. Both methods afford information regarding the molecular state of HQ adsorbed at the Pt(111) surface. Copyright 1999 Academic Press. PMID:9885274

  10. Electrical characterization of graphene oxide and organic dielectric layers based on thin film transistor

    International Nuclear Information System (INIS)

    Highlights: • We report the synthesis of graphene oxide nanosheets and electrical characterization of graphene oxide based thin film transistor. • Graphene oxide (GO) nanosheets were prepared by using modified Hummers method. • We used insulator layers which are polymethylmethacrylate (PMMA) and polyvinyl phenol (PVP) for graphene oxide based thin flim transistor. - Abstract: We have studied the electrical characteristics of graphene oxide based thin flim transistor with the polymer insulators such as polymethyl methacrylate (PMMA) and poly-4-vinylphenol (PVP). Graphene oxide (GO) nanosheets were prepared by using modified Hummers method. The structural properties of GO nanosheets were characterized with Ultraviolet Visible (UV–vis), FT-IR spectroscopy and X-rays diffraction (XRD). Graphene oxide based thin flim transistor (GO-TFT) was prepared by a spin-coating and thermal evaporation technique. The electrical characterization of GO-TFT was analyzed by output and transfer characteristics by using Keithley-4200 semiconductor characterization system (SCS). The graphene oxide based thin flim transistor devices show p-type semiconducting behavior. The mobility, threshold voltage, sub-threshold swing value and Ion/Ioff of GO-TFT were found to be 0.105 cm2 V−1 s−1, −8.7 V, 4.03 V/decade and 10, respectively

  11. Semiconductor thin film transfer by wafer bonding and advanced ion implantation layer splitting technologies

    Science.gov (United States)

    Lee, Tien-Hsi

    Wafer bonding is an attractive technology for modern semiconductor and microelectronic industry due to its variability in allowing combination of materials. Initially, the bonding of wafers of the same material, such as silicon-silicon wafer bonding has been major interest. In the meantime, research interest has shifted to the bonding of dissimilar materials such as silicon to quartz or to sapphire. Thermal stress coming from the different expansion coefficients usually is a barrier to the success of dissimilar material bonding. Thermal stress may cause debonding, sliding, cracking, thermal misfit dislocations, or film wrinkle to impair the quality of the transferred layer. This dissertation presents several effective approaches to solve the thermal stress problem. These approaches concern bonding processes (low vacuum bonding and storage), thinning (advanced ion implantation layer splitting), and annealing processes (accumulative effect of blister generation) and are combined to design the best heat-treatment cycle. For this propose the concept of hot bonding is used in order to effectively minimize the thermal mismatch of dissimilar material bonding during the bonding and thinning procedures. During the initial bonding and bond strengthening phase, the difference in the temperature between bonding and annealing processes should be decreased as much as possible to avoid excessive thermal stresses. This concept can be realized either by increasing the bonding temperature or by decreasing the annealing temperature. A thinning technique has to employed that can thin the device wafer before debonding occurs due to the thermal stress generated either from the cooling-down process in the first case or by the annealing process itself in the late case. The ion implantation layer splitting method, also known as the Smart-cutsp°ler process, developed by Bruel at LEIT in France is a practical thinning technique which satisfies the above requirement. In the study, an

  12. Growth of polycrystalline CdS and CdTe thin layers for high efficiency thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Romeo, N.; Bosio, A.; Tedeschi, R.; Canevari, V. [Parma Univ. (Italy). Dipartimento di Fisica

    2000-10-16

    Recently, conversion efficiencies close to 16% for thin film solar cells based on the CdS/CdTe heterojunction have been reported. These relevant results, however, have not yet solved the problems which arise when industrial production is undertaken as the demand for low cost imposes constraints which considerably limit the final efficiency of the cells. In this paper, we will show that very high conversion efficiencies can still be achieved even making use of low cost soda-lime glass as substrate. In fact, the Na contained in this kind of glass diffuses during the fabrication of the cell into the active layers of the device causing a substantial decrease of the fill factor and consequently of the efficiency of the cell. In particular, we will describe the methods and the magnetron sputtering techniques used to grow a polycrystalline CdS thin film with a controlled Na content. We will also describe the details of the growth via the close-spaced sublimation (CSS) technique of the CdTe polycrystalline film, which are crucial for the heterojunction and the back contact which has been fabricated exploiting the characteristics of Sb{sub 2}Te{sub 3} which is a low gap p-type semiconductor with a high conductivity. (orig.)

  13. Boundary layer correctors and generalized polarization tensor for periodic rough thin layers. A review for the conductivity problem

    Directory of Open Access Journals (Sweden)

    Poignard Clair

    2012-09-01

    Full Text Available We study the behaviour of the steady-state voltage potential in a material composed of a two-dimensional object surrounded by a rough thin layer and embedded in an ambient medium. The roughness of the layer is supposed to be εα–periodic, ε being the magnitude of the mean thickness of the layer, and α a positive parameter describing the degree of roughness. For ε tending to zero, we determine the appropriate boundary layer correctors which lead to approximate transmission conditions equivalent to the effect of the rough thin layer. We also provide an explicit characterization of the polarization tensor as defined by Capdeboscq and Vogelius in [9]. The present paper revisits the previous works of the author [11, 13, 16, 17], and it also provides new results for the very rough case α > 1. Dans cet article, nous considérons le problème de conduction dans un domaine bidimensionnel composé d’une fine membrane rugueuse entourant un domaine conducteur, le tout plongé dans un milieu ambiant de conductivité différente. La rugosité de la membrane est supposée εα–périodique, ε étant l’épaisseur moyenne de la membrane, et α un paramètre positif décrivant le degré de rugosité. Nous déterminons des correcteurs de couche limite conduisant à la construction de conditions de transmission approchées lorsque le paramètre ε tend vers zero. Nous donnons aussi une caractérisation explicite du tenseur de polarisation défini par Capdeboscq and Vogelius dans [9]. Cet article revisite des résultats précédents de l’auteur obtenus dans [11, 13, 16, 17], et présente de nouveaux résultats pour le cas très rugueux α > 1.

  14. White organic light-emitting diodes with an ultra-thin premixed emitting layer

    CERN Document Server

    Jeon, T; Tondelier, Denis; Bonnassieux, Yvan; Forget, Sebastien; Chenais, Sebastien; Ishow, Elena

    2014-01-01

    We described an approach to achieve fine color control of fluorescent White Organic Light-Emitting Diodes (OLED), based on an Ultra-thin Premixed emitting Layer (UPL). The UPL consists of a mixture of two dyes (red-emitting 4-di(4'-tert-butylbiphenyl-4-yl)amino-4'-dicyanovinylbenzene or fvin and green-emitting 4-di(4'-tert-butylbiphenyl-4-yl)aminobenzaldehyde or fcho) premixed in a single evaporation cell: since these two molecules have comparable structures and similar melting temperatures, a blend can be evaporated, giving rise to thin films of identical and reproducible composition compared to those of the pre-mixture. The principle of fine color tuning is demonstrated by evaporating a 1-nm-thick layer of this blend within the hole-transport layer (4,4'-bis[N-(1-naphtyl)-N-phenylamino]biphenyl (\\alpha-NPB)) of a standard fluorescent OLED structure. Upon playing on the position of the UPL inside the hole-transport layer, as well as on the premix composition, two independent parameters are available to finel...

  15. Sound transmission through finite lightweight multilayered structures with thin air layers.

    Science.gov (United States)

    Dijckmans, A; Vermeir, G; Lauriks, W

    2010-12-01

    The sound transmission loss (STL) of finite lightweight multilayered structures with thin air layers is studied in this paper. Two types of models are used to describe the vibro-acoustic behavior of these structures. Standard transfer matrix method assumes infinite layers and represents the plane wave propagation in the layers. A wave based model describes the direct sound transmission through a rectangular structure placed between two reverberant rooms. Full vibro-acoustic coupling between rooms, plates, and air cavities is taken into account. Comparison with double glazing measurements shows that this effect of vibro-acoustic coupling is important in lightweight double walls. For infinite structures, structural damping has no significant influence on STL below the coincidence frequency. In this frequency region, the non-resonant transmission or so-called mass-law behavior dominates sound transmission. Modal simulations suggest a large influence of structural damping on STL. This is confirmed by experiments with double fiberboard partitions and sandwich structures. The results show that for thin air layers, the damping induced by friction and viscous effects at the air gap surfaces can largely influence and improve the sound transmission characteristics. PMID:21218884

  16. Electrochemical Examination of the Structure of Thin Hydrogel Layers Anchored to Regular and Microelectrode Surfaces.

    Science.gov (United States)

    Kaniewska, Klaudia; Karbarz, Marcin; Ziach, Krzysztof; Siennicka, Alicja; Stojek, Zbigniew; Hyk, Wojciech

    2016-09-01

    For the examination of hydrogel structure, thin layers of thermoresponsive gels based on poly(N-isopropylacrylamide) (pNIPA) and copolymer poly(N-isopropylacrylamide-co-sodium acrylate) (p(NIPA-co-AS)) were successfully anchored to microelectrode and regular electrode surfaces using the electrochemically induced free radical polymerization. The obtained layers were stable and covered the entire surface of the electrodes. Electroactive probes 1,1'-ferrocenedimethanol (Fc(CH2OH)2) and synthesized derivatives of ferrocene modified with polyethylene glycol units (Fc-PEGn) of various length (n = 4, 9, 75, and 135) were employed for studying the volume phase transition of the thin hydrogel layers and for the determination of their structural parameters. The quantitative information on the structural parameters of the hydrogel layers was derived from the obstruction model for diffusion using the voltammetrically determined diffusion coefficients for the model redox probe Fc(CH2OH)2. An approach to the determination of the effective radii of the gel openings (channels) for pNIPA and p(NIPA-co-AS) microlayers was developed. The obtained results were matched with the experimental results and allowed derivation of quantitative conclusions. The voltammograms obtained with modified electrodes in solutions containing Fc-PEG4, Fc-PEG9, and Fc-PEG75 were well defined and of appropriate height. However, the voltammograms recorded for Fc-PEG135, the hydrodynamic radius of which exceeded the size of the gel channels, were at the baseline level. PMID:27518807

  17. Electrochemical Examination of the Structure of Thin Hydrogel Layers Anchored to Regular and Microelectrode Surfaces.

    Science.gov (United States)

    Kaniewska, Klaudia; Karbarz, Marcin; Ziach, Krzysztof; Siennicka, Alicja; Stojek, Zbigniew; Hyk, Wojciech

    2016-09-01

    For the examination of hydrogel structure, thin layers of thermoresponsive gels based on poly(N-isopropylacrylamide) (pNIPA) and copolymer poly(N-isopropylacrylamide-co-sodium acrylate) (p(NIPA-co-AS)) were successfully anchored to microelectrode and regular electrode surfaces using the electrochemically induced free radical polymerization. The obtained layers were stable and covered the entire surface of the electrodes. Electroactive probes 1,1'-ferrocenedimethanol (Fc(CH2OH)2) and synthesized derivatives of ferrocene modified with polyethylene glycol units (Fc-PEGn) of various length (n = 4, 9, 75, and 135) were employed for studying the volume phase transition of the thin hydrogel layers and for the determination of their structural parameters. The quantitative information on the structural parameters of the hydrogel layers was derived from the obstruction model for diffusion using the voltammetrically determined diffusion coefficients for the model redox probe Fc(CH2OH)2. An approach to the determination of the effective radii of the gel openings (channels) for pNIPA and p(NIPA-co-AS) microlayers was developed. The obtained results were matched with the experimental results and allowed derivation of quantitative conclusions. The voltammograms obtained with modified electrodes in solutions containing Fc-PEG4, Fc-PEG9, and Fc-PEG75 were well defined and of appropriate height. However, the voltammograms recorded for Fc-PEG135, the hydrodynamic radius of which exceeded the size of the gel channels, were at the baseline level.

  18. Molecular Layer-seeded Ultra-thin Top-gate Dielectrics for High Transconductance Graphene Transistors

    Science.gov (United States)

    Sangwan, Vinod; Jariwala, Deep; Karmel, Hunter; Alaboson, Justice; Lauhon, Lincoln; Marks, Tobin; Hersam, Mark

    2012-02-01

    The potential of graphene in integrated analog and digital circuits can only be fully realized through incorporation of ultra-thin gate dielectrics to enable large-scale small-channel graphene field-effect transistors (GFETs). Atomic-layer deposition (ALD) is a viable technique to fabricate gate-dielectrics, however, it requires a seeding layer on otherwise inert graphene. Here, we demonstrate a single molecule thick perylene-3,4,9,10-tetracarboxylic dianhydride overlayer as an effective seeding layer to grow high-κ Al2O3 on mechanically exfoliated graphene for high-performance GFETs. Using an ultra-thin (films (5-10 nm), we demonstrate fabrication of the thinnest ALD-grown gate-dielectric (4 nm) reported to date in top-gated GFETs. This yields high performance GFETs with the intrinsic transconductance parameter approaching 2.4 mS and the field-effect mobility ˜3000 cm^2/Vs. We also demonstrate generalization of this molecular layer seeded-ALD growth method to higher- κ gate dielectrics, yielding further enhanced GFET transconductance for possible application to radio-frequency circuits.

  19. Organic and inorganic-organic thin film structures by molecular layer deposition: A review.

    Science.gov (United States)

    Sundberg, Pia; Karppinen, Maarit

    2014-01-01

    The possibility to deposit purely organic and hybrid inorganic-organic materials in a way parallel to the state-of-the-art gas-phase deposition method of inorganic thin films, i.e., atomic layer deposition (ALD), is currently experiencing a strongly growing interest. Like ALD in case of the inorganics, the emerging molecular layer deposition (MLD) technique for organic constituents can be employed to fabricate high-quality thin films and coatings with thickness and composition control on the molecular scale, even on complex three-dimensional structures. Moreover, by combining the two techniques, ALD and MLD, fundamentally new types of inorganic-organic hybrid materials can be produced. In this review article, we first describe the basic concepts regarding the MLD and ALD/MLD processes, followed by a comprehensive review of the various precursors and precursor pairs so far employed in these processes. Finally, we discuss the first proof-of-concept experiments in which the newly developed MLD and ALD/MLD processes are exploited to fabricate novel multilayer and nanostructure architectures by combining different inorganic, organic and hybrid material layers into on-demand designed mixtures, superlattices and nanolaminates, and employing new innovative nanotemplates or post-deposition treatments to, e.g., selectively decompose parts of the structure. Such layer-engineered and/or nanostructured hybrid materials with exciting combinations of functional properties hold great promise for high-end technological applications. PMID:25161845

  20. Understanding geometric instabilities in thin films via a multi-layer model.

    Science.gov (United States)

    Lejeune, Emma; Javili, Ali; Linder, Christian

    2016-01-21

    When a thin stiff film adhered to a compliant substrate is subject to compressive stresses, the film will experience a geometric instability and buckle out of plane. For high film/substrate stiffness ratios with relatively low levels of strain, the primary mode of instability will either be wrinkling or buckling delamination depending on the material and geometric properties of the system. Previous works approach these systems by treating the film and substrate as homogenous layers, either consistently perfectly attached, or perfectly unattached at interfacial flaws. However, this approach neglects systems where the film and substrate are uniformly weakly attached or where interfacial layers due to surface modifications in either the film or substrate are present. Here we demonstrate a method for accounting for these additional thin surface layers via an analytical solution verified by numerical results. The main outcome of this work is an improved understanding of how these layers influence global behavior. We demonstrate the utility of our model with applications ranging from buckling based metrology in ultrathin films, to an improved understanding of the formation of a novel surface in carbon nanotube bio-interface films. Moving forward, this model can be used to interpret experimental results, particularly for systems which deviate from traditional behavior, and aid in the evaluation and design of future film/substrate systems.

  1. Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles

    Indian Academy of Sciences (India)

    MAGDALENA BARWIOLEK; ROBERT SZCZĘSNY; EDWARD SZŁYK

    2016-07-01

    Cu(II) complexes with Schiff bases derived from ethylenediamine (en) and 2-pyridinecarboxaldehyde (pyca), 2,5-dimethoxybenzaldehyde (dmbaH) or 4-imidazolecarboxaldehyde (4Him) were obtained and studied by elemental analysis, UV-VIS and IR spectra. Zinc oxide was synthesized using a simple homogeneous precipitation method with zinc acetate as a starting material. Thin layers of the studied Cu(II) complexes were deposited on Si(111) or ZnO/Si(111) substrates by a spin coating method and characterized with a scanningelectron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectroscopy. For Cu(II) layers the most intensive fluorescence bands due to intra-ligand transitions were observed between 462 and 503 nm. The fluorescence intensity of thin layers was corelated to the rotation speed. In the case of the [Cu(II)(en(4Him)₂)Cl₂](2a)/ZnO/Si and [Cu(en(dmbaH)₂)Cl₂](3a)/ZnO/Si layers the quenching of the emission band from ZnO at 440 nm (λex = 330 nm) associated with various intrinsic or extrinsic lattice defects was noted.

  2. Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H., E-mail: ted.sargent@utoronto.ca [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); Kinge, Sachin [Advanced Technology, Materials and Research, Research and Development, Hoge Wei 33- Toyota Technical Centre, B-1930 Zaventem (Belgium)

    2015-10-12

    Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO{sub 2} layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10{sup −2} A W{sup −1} and a shot-derived specific detectivity of 3 × 10{sup 9} Jones at 1530 nm wavelength.

  3. Organic and inorganic–organic thin film structures by molecular layer deposition: A review

    Directory of Open Access Journals (Sweden)

    Pia Sundberg

    2014-07-01

    Full Text Available The possibility to deposit purely organic and hybrid inorganic–organic materials in a way parallel to the state-of-the-art gas-phase deposition method of inorganic thin films, i.e., atomic layer deposition (ALD, is currently experiencing a strongly growing interest. Like ALD in case of the inorganics, the emerging molecular layer deposition (MLD technique for organic constituents can be employed to fabricate high-quality thin films and coatings with thickness and composition control on the molecular scale, even on complex three-dimensional structures. Moreover, by combining the two techniques, ALD and MLD, fundamentally new types of inorganic–organic hybrid materials can be produced. In this review article, we first describe the basic concepts regarding the MLD and ALD/MLD processes, followed by a comprehensive review of the various precursors and precursor pairs so far employed in these processes. Finally, we discuss the first proof-of-concept experiments in which the newly developed MLD and ALD/MLD processes are exploited to fabricate novel multilayer and nanostructure architectures by combining different inorganic, organic and hybrid material layers into on-demand designed mixtures, superlattices and nanolaminates, and employing new innovative nanotemplates or post-deposition treatments to, e.g., selectively decompose parts of the structure. Such layer-engineered and/or nanostructured hybrid materials with exciting combinations of functional properties hold great promise for high-end technological applications.

  4. Growth of b-axis oriented VO2 thin films on glass substrates using ZnO buffer layer

    International Nuclear Information System (INIS)

    VO2 thin films are grown on glass substrates by pulsed laser deposition using vanadium metal as a target. In this study, a ZnO thin film was used as a buffer layer for the growth of VO2 thin films on glass substrates. X-ray diffraction studies showed that the VO2 thin film had b-axis preferential orientation on a c-axis oriented ZnO buffer layer. The thickness of the ZnO buffer layer and the oxygen pressure during VO2 deposition were optimized to grow highly b-axis oriented VO2 thin films. The metal-insulator transition properties of the VO2 film samples were investigated in terms of infrared reflectance and electrical resistance with varying temperatures.

  5. Assessment of doses caused by electrons in thin layers of tissue-equivalent materials, using MCNP.

    Science.gov (United States)

    Heide, Bernd

    2013-10-01

    Absorbed doses caused by electron irradiation were calculated with Monte Carlo N-Particle transport code (MCNP) for thin layers of tissue-equivalent materials. The layers were so thin that the calculation of energy deposition was on the border of the scope of MCNP. Therefore, in this article application of three different methods of calculation of energy deposition is discussed. This was done by means of two scenarios: in the first one, electrons were emitted from the centre of a sphere of water and also recorded in that sphere; and in the second, an irradiation with the PTB Secondary Standard BSS2 was modelled, where electrons were emitted from an (90)Sr/(90)Y area source and recorded inside a cuboid phantom made of tissue-equivalent material. The speed and accuracy of the different methods were of interest. While a significant difference in accuracy was visible for one method in the first scenario, the difference in accuracy of the three methods was insignificant for the second one. Considerable differences in speed were found for both scenarios. In order to demonstrate the need for calculating the dose in thin small zones, a third scenario was constructed and simulated as well. The third scenario was nearly equal to the second one, but a pike of lead was assumed to be inside the phantom in addition. A dose enhancement (caused by the pike of lead) of ∼113 % was recorded for a thin hollow cylinder at a depth of 0.007 cm, which the basal-skin layer is referred to in particular. Dose enhancements between 68 and 88 % were found for a slab with a radius of 0.09 cm for all depths. All dose enhancements were hardly noticeable for a slab with a cross-sectional area of 1 cm(2), which is usually applied to operational radiation protection.

  6. Fabrication of (110)-one-axis-oriented perovskite-type oxide thin films and their application to buffer layer

    Science.gov (United States)

    Sato, Tomoya; Ichinose, Daichi; Kimura, Junichi; Inoue, Takaaki; Mimura, Takanori; Funakubo, Hiroshi; Uchiyama, Kiyoshi

    2016-10-01

    BaCe0.9Y0.1O3-δ (BCYO) and SrZr0.8Y0.2O3-δ (SZYO) thin films of perovskite-type oxides were deposited on (111)Pt/TiO x /SiO2/(100)Si substrates. X-ray diffraction patterns showed that the (110)-oriented BCYO and SZYO thin films were grown on (111)Pt/Si substrates directly without using any buffer layers. Thin films of SrRuO3 (SRO), a conductive perovskite-type oxide, were also deposited on those films and highly (110)-oriented SRO thin films were obtained. We believe that this (110)-oriented SRO works as a buffer layer to deposit (110)-oriented perovskite-type ferroelectric oxide thin films as well as a bottom electrode and can modify the ferroelectric properties of the oxide thin films by controlling their crystallographic orientations.

  7. Mass Transport in a Thin Layer of Bi-Viscous Mud Under Surface Waves

    Institute of Scientific and Technical Information of China (English)

    NG Chiu-on; FU Sau-chung; BAI Yu-chuan(白玉川)

    2002-01-01

    The mass transport in a thin layer of non-Newtonian bed mud under surface waves is examined with a two-fluidStokes boundary layer model. The mud is assumed to be a bi-viscous fluid, which tends to resist motion for small-appliedstresses, but flows readily when the yield stress is exceeded. Asymptotic expansions suitable for shallow fluid layers areapplied, and the second-order solutions for the mass transport induced by surface progressive waves are obtained numeri-cally. It is found that the stronger the non-Newtonian behavior of the mud, the more pronounced intermittency of theflow. Consequently, the mass transport velocity is diminished in magnitude, and can even become negative (i. e., oppo-site to wave propagation) for a certain range of yield stress.

  8. Epitaxial TiN(001) wetting layer for growth of thin single-crystal Cu(001)

    Energy Technology Data Exchange (ETDEWEB)

    Chawla, J. S.; Zhang, X. Y.; Gall, D. [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2011-08-15

    Single-crystal Cu(001) layers, 4-1400 nm thick, were deposited on MgO(001) with and without a 2.5-nm-thick TiN(001) buffer layer. X-ray diffraction and reflection indicate that the TiN(001) surface suppresses Cu-dewetting, yielding a 4 x lower defect density and a 9 x smaller surface roughness than if grown on MgO(001) at 25 deg. C. In situ and low temperature electron transport measurements indicate that ultra-thin (4 nm) Cu(001) remains continuous and exhibits partial specular scattering at the Cu-vacuum boundary with a Fuchs-Sondheimer specularity parameter p = 0.6 {+-} 0.2, suggesting that the use of epitaxial wetting layers is a promising approach to create low-resistivity single-crystal Cu nanoelectronic interconnects.

  9. Significant Improvement of Organic Thin-Film Transistor Mobility Utilizing an Organic Heterojunction Buffer Layer

    Institute of Scientific and Technical Information of China (English)

    PAN Feng; QIAN Xian-Rui; HUANG Li-Zhen; WANG Hai-Bo; YAN Dong-Hang

    2011-01-01

    High-mobility vanadyl phthalocyanine (VOPc)/5,5″′-bis(4-fluorophenyl)-2,2′:5′,2″:5″,2″′-quaterthiophene (F2-P4T) thin-film transistors are demonstrated by employing a copper hexadecafluorophthalocyanine (F16 CuPc)/copper phthalocyanine (CuPc) heterojunction unit,which are fabricated at different substrate temperatures,as a buffer layer. The highest mobility of 4.08cm2/Vs is achieved using a F16CuPc/CuPc organic heterojunction buffer layer fabricated at high substrate temperature.Compared with the random small grain-like morphology of the room-temperature buffer layer,the high-temperature organic heterojunction presents a large-sized fiber-like film morphology,resulting in an enhanced conductivity.Thus the contact resistance of the transistor is significantly reduced and an obvious improvement in device mobility is obtained.

  10. Evolution of thin protecting Si-layer on Mn{sub 0.5}Si{sub 0.5} layer at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Yuanmin; Wu, Shan [Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433 (China); Collaborative Innovation Center of Microstructures, Nanjing 210093 (China); Zhang, Zhi; Zou, Jin [Materials Engineering and Centre for Microscopy and Microanalysis, The University of Queensland, QLD 4072 (Australia); Jiang, Zuimin, E-mail: zmjiang@fudan.edu.cn [Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433 (China); Collaborative Innovation Center of Microstructures, Nanjing 210093 (China)

    2015-04-01

    Highlights: • Evolution of 2-nm-thick protecting Si-layer on Mn{sub 0.5}Si{sub 0.5} film was studied by CAFM. • Many SiO{sub 2} islands were found to form on the surface at 300 °C. • Si cap layer first oxidized and then agglomerated into SiO{sub 2} islands. • Protection capability of Si cap layer degraded after agglomeration of thin SiO{sub 2} layer. • Mechanism of agglomeration of thin SiO{sub 2} layer is discussed. - Abstract: Evolution of 2-nm-thick protecting Si-layer on amorphous Mn{sub 0.5}Si{sub 0.5} films at elevated temperatures was investigated by using conductive atom force microscopy (CAFM) and other structure and composition characterization methods. At a temperature of 300 °C, a dramatic change was observed in surface morphology with many islands forming on the surface. Those islands were SiO{sub 2} islands rather than Si ones. Further studies showed that those islands formed via first oxidation of the Si cap layer followed by the agglomeration of this SiO{sub 2} layer. Because Si cap layer has widely been used as protecting materials to prevent the surface from oxidizing and contamination, this study provides an insight on the effectiveness of thin protecting Si-layer at low temperatures.

  11. Large-Area Growth of Uniform Single-Layer MoS2 Thin Films by Chemical Vapor Deposition.

    Science.gov (United States)

    Baek, Seung Hyun; Choi, Yura; Choi, Woong

    2015-12-01

    We report the largest-size thin films of uniform single-layer MoS2 on sapphire substrates grown by chemical vapor deposition based on the reaction of gaseous MoO3 and S evaporated from solid sources. The as-grown thin films of single-layer MoS2 were continuous and uniform in thickness for more than 4 cm without the existence of triangular-shaped MoS2 clusters. Compared to mechanically exfoliated crystals, the as-grown single-layer MoS2 thin films possessed consistent chemical valence states and crystal structure along with strong photoluminescence emission and optical absorbance at high energy. These results demonstrate that it is possible to scale up the growth of uniform single-layer MoS2 thin films, providing potentially important implications on realizing high-performance MoS2 devices.

  12. Recent Methods for the Automatic Evaluation of Thin-Layer and Paper Chromatograms of Labelled Substances

    International Nuclear Information System (INIS)

    The development and results obtained with a new instrument for the automatic scanning of thin-layer and paper chromatograms of labelled substances is described. Using a novel type of gas-flow detector, it is possible to measure all beta-emitters, including 3H, without contact with the probe. Essentially the apparatus consists of a detector and a transport mechanism passing the chromatogram below the detector diaphragm. In view of the small half-value layer of beta-particles in air (approx. 0.3 mm) a strong dependence on distance between detector and chromatogram would be expected. However, there is practically no dependence between 0.5 and 2 mm distance. The explanation presented is that because of the special counter parameters the electrical field extends through the opening of the diaphragm into the space between counter and chromatogram, thereby pulling negative charge carriers produced by ionizing radiation even outside the counter volume into the region of gas amplification around the anode wire. Therefore, the instrument allows fast, direct and non-destructive measurement of thin-layer plates even for 3H, as opposed to the common practice of scraping off small areas of the thin layer and measuring the radioactivity in a liquid scintillation counter. The transport mechanism in its most recent version allows two-dimensional automatic scanning, with continuous or stepwise advance, and correspondingly analogous or digital registration. A ''dot'' recording allows simple visualization of the chromatogram, similar to an autoradiograph, however, in a much shorter time. Small available diaphragm openings down to 0.2 x 2 mm make the instrument useful also for histological preparations and small animal scanning. The instrument is also used for evaluating doubly-labelled chromatograms, for instance separate measurement of 3H and 14C activity in one chromatogram. (author)

  13. Double-layer indium doped zinc oxide for silicon thin-film solar cell prepared by ultrasonic spray pyrolysis

    Institute of Scientific and Technical Information of China (English)

    Jiao Bao-Chen; Zhang Xiao-Dan; Wei Chang-Chun; Sun Jian; Ni Jian; Zhao Ying

    2011-01-01

    Indium doped zinc oxide (ZnO:In) thin films were prepared by ultrasonic spray pyrolysis on corning eagle 2000 glass substrate. 1 and 2 at.% indium doped single-layer ZnO:In thin films with different amounts of acetic acid added in the initial solution were fabricated. The 1 at.% indium doped single-layers have triangle grains. The 2 at.% indium doped single-layer with 0.18 acetic acid adding has the resistivity of 6.82 × 10-3 Ω· cm and particle grains. The double-layers structure is designed to fabricate the ZnO:In thin film with low resistivity (2.58×10-3 Ω· cm) and good surface morphology. It is found that the surface morphology of the double-layer ZnO:In film strongly depends on the substrate-layer, and the second-layer plays a large part in the resistivity of the double-layer ZnO:In thin film. Both total and direct transmittances of the double-layer ZnO:In film are above 80% in the visible light region. Single junction a-Si:H solar cell based on the double-layer ZnO:In as front electrode is also investigated.

  14. Indium sulfide thin films as window layer in chemically deposited solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lugo-Loredo, S. [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico); Peña-Méndez, Y., E-mail: yolapm@gmail.com [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico); Calixto-Rodriguez, M. [Universidad Tecnológica Emiliano Zapata del Estado de Morelos, Av. Universidad Tecnológica No. 1, C.P. 62760 Emiliano Zapata, Morelos (Mexico); Messina-Fernández, S. [Universidad Autónoma de Nayarit, Ciudad de la Cultura “Amado Nervo” S/N, C.P. 63190 Tepic, Nayarit (Mexico); Alvarez-Gallegos, A. [Universidad Autónoma del Estado de Morelos, Centro de Investigación en Ingeniería y Ciencias Aplicadas, Av. Universidad 1001, C.P. 62209, Cuernavaca Morelos (Mexico); Vázquez-Dimas, A.; Hernández-García, T. [Universidad Autónoma de Nuevo León, UANL, Fac. de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria San Nicolás de Los Garza Nuevo León, C.P. 66451 (Mexico)

    2014-01-01

    Indium sulfide (In{sub 2}S{sub 3}) thin films have been synthesized by chemical bath deposition technique onto glass substrates using In(NO{sub 3}){sub 3} as indium precursor and thioacetamide as sulfur source. X-ray diffraction studies have shown that the crystalline state of the as-prepared and the annealed films is β-In{sub 2}S{sub 3}. Optical band gap values between 2.27 and 2.41 eV were obtained for these films. The In{sub 2}S{sub 3} thin films are photosensitive with an electrical conductivity value in the range of 10{sup −3}–10{sup −7} (Ω cm){sup −1}, depending on the film preparation conditions. We have demonstrated that the In{sub 2}S{sub 3} thin films obtained in this work are suitable candidates to be used as window layer in thin film solar cells. These films were integrated in SnO{sub 2}:F/In{sub 2}S{sub 3}/Sb{sub 2}S{sub 3}/PbS/C–Ag solar cell structures, which showed an open circuit voltage of 630 mV and a short circuit current density of 0.6 mA/cm{sup 2}. - Highlights: • In{sub 2}S{sub 3} thin films were deposited using the Chemical Bath Deposition technique. • A direct energy band gap between 2.41 to 2.27 eV was evaluated for the In{sub 2}S{sub 3} films. • We made chemically deposited solar cells using the In{sub 2}S{sub 3} thin films.

  15. Temperature stability of ultra-thin mixed BaSr-oxide layers and their transformation.

    Science.gov (United States)

    Müller-Sajak, D; Islam, S; Pfnür, H; Hofmann, K R

    2012-08-01

    In the context of investigations of physical, chemical and electrical properties of ultra-thin layers of epitaxial and monocrystalline Sr(0.3)Ba(0.7)O on Si(100), we also investigated their thermal stability with x-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS), and low energy electron diffraction (LEED). At temperatures above 400 °C, transformation into silicate layers sets in. The stoichiometry after complete transformation was determined to be close to (Ba(0.8)Sr(0.2))(2)SiO(4) except for layers of only a few monolayers, where the silicate is not stoichiometric. There are strong indications that this silicate is stable until it desorbs at temperatures above 750 °C. Crystallinity, as seen with LEED, is lost during this transformation. Although transformation into silicate is coupled with metal desorption and compactification of the layers, they seem to remain closed. In addition, traces of Ba silicide at the Si interface were detected after layer desorption. This silicide cannot be desorbed thermally. The silicate layer has a bandgap of 5.9 ± 0.2 eV already for 3 ML thickness. Upon exposure to air, carbon and oxygen containing species, but no hydroxide, are formed irreversibly.

  16. Deposition and characterization of (Zn,Mg)O buffer layers on CIGSSe thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hussmann, Benjamin; Erfurth, Felix; Schoell, Achim [Universitaet Wuerzburg (Germany). Experimentelle Physik II; Niesen, Thomas; Palm, Joerg [Avancis GmbH, Muenchen (Germany); Grimm, Alexander [Hahn-Meitner-Institut Berlin (Germany); Umbach, Eberhard [Universitaet Wuerzburg (Germany). Experimentelle Physik II; Forschungszentrum Karlsruhe (Germany)

    2008-07-01

    (Zn, Mg)O buffer layers on Cu(In,Ga)(S,Se){sub 2}(CIGSSe) thin film solar cells are promising alternatives to CdS buffer layers by featuring comparable efficiencies, better environmental compatibility and the possibility to implement the deposition process into a vacuum processing line. The (Zn,Mg)O buffer layers are deposited by radio frequency magnetron co-sputtering from two separate ZnO and MgO ceramic sputter targets to control the Mg-content and therefore the band gap of the buffer layer. In our experimental setup the sputter preparation chamber is connected with a UHV analysis system which allows in-situ characterization with X-ray photoelectron spectroscopy (XPS). The interface between the absorber and the buffer layer is believed to have a major influence on the cell efficiency and is thus of particular interest in this work. This interface has been investigated during layer deposition by sequentially interrupting the sputter process and performing XPS scans. We observed island growth of (Zn,Mg)O on CIGSSe and a strong oxidation of the absorber surface induced by the deposit. In order to complement the chemical and electronic information with structural data, energy dispersive X-ray analysis, X-ray diffraction, and scanning electron microscopy have been applied.

  17. Bimodal Latex Effect on Spin-Coated Thin Conductive Polymer-Single-Walled Carbon Nanotube Layers.

    Science.gov (United States)

    Moradi, Mohammad-Amin; Larrakoetxea Angoitia, Katalin; van Berkel, Stefan; Gnanasekaran, Karthikeyan; Friedrich, Heiner; Heuts, Johan P A; van der Schoot, Paul; van Herk, Alex M

    2015-11-10

    We synthesize two differently sized poly(methyl methacrylate-co-tert-butyl acrylate) latexes by emulsion polymerization and mix these with a sonicated single-walled carbon nanotube (SWCNT) dispersion, in order to prepare 3% SWCNT composite mixtures. We spin-coat these mixtures at various spin-speed rates and spin times over a glass substrate, producing a thin, transparent, solid, conductive layer. Keeping the amount of SWCNTs constant, we vary the weight fraction of our smaller 30-nm latex particles relative to the larger 70-nm-sized ones. We find a maximum in the electrical conductivity up to 370 S/m as a function of the weight fraction of smaller particles, depending on the overall solid content, the spin speed, and the spin time. This maximum occurs at 3-5% of the smaller latex particles. We also find a more than 2-fold increase in conductivity parallel to the radius of spin-coating than perpendicular to it. Atomic force microscopy points at the existence of lanes of latex particles in the spin-coated thin layer, while large-area transmission electron microscopy demonstrates that the SWCNTs are aligned over a grid fixed on the glass substrate during the spin-coating process. We extract the conductivity distribution on the surface of the thin film and translate this into the direction of the SWCNTs in it.

  18. Bimodal Latex Effect on Spin-Coated Thin Conductive Polymer-Single-Walled Carbon Nanotube Layers.

    Science.gov (United States)

    Moradi, Mohammad-Amin; Larrakoetxea Angoitia, Katalin; van Berkel, Stefan; Gnanasekaran, Karthikeyan; Friedrich, Heiner; Heuts, Johan P A; van der Schoot, Paul; van Herk, Alex M

    2015-11-10

    We synthesize two differently sized poly(methyl methacrylate-co-tert-butyl acrylate) latexes by emulsion polymerization and mix these with a sonicated single-walled carbon nanotube (SWCNT) dispersion, in order to prepare 3% SWCNT composite mixtures. We spin-coat these mixtures at various spin-speed rates and spin times over a glass substrate, producing a thin, transparent, solid, conductive layer. Keeping the amount of SWCNTs constant, we vary the weight fraction of our smaller 30-nm latex particles relative to the larger 70-nm-sized ones. We find a maximum in the electrical conductivity up to 370 S/m as a function of the weight fraction of smaller particles, depending on the overall solid content, the spin speed, and the spin time. This maximum occurs at 3-5% of the smaller latex particles. We also find a more than 2-fold increase in conductivity parallel to the radius of spin-coating than perpendicular to it. Atomic force microscopy points at the existence of lanes of latex particles in the spin-coated thin layer, while large-area transmission electron microscopy demonstrates that the SWCNTs are aligned over a grid fixed on the glass substrate during the spin-coating process. We extract the conductivity distribution on the surface of the thin film and translate this into the direction of the SWCNTs in it. PMID:26491888

  19. Long-range surface plasmon polaritons at THz frequencies in thin semiconductor layers

    Institute of Scientific and Technical Information of China (English)

    Yichen Zhang; Audrey Berrier; Jaime Gómez Rivas

    2011-01-01

    Surface plasmon polaritons (SPPs) are electromagnetic waves coupled to the free charge carriers at the interface between a metal and a dielectric[1].These waves propagate along the interface,while decaying evanescently away from it.The propagation length of SPPs is mainly limited by Ohmic losses in the metal.A possible way to lower these losses is to reduce the penetration of the electromagnetic field inside the metal,which can be achieved by coupling the SPPs at the opposite sides of a thin metallic film.These coupled SPPs are known as long-range surface plasmon polaritons (LRSPPs) and have been thoroughly investigated at optical frequencies in thin layers of noble metals[2].%We present a theoretical investigation of THz long-range surface plasmon polaritons propagating on thin layers of InSb. The metallic behavior of doped semiconductors at THz frequencies allows the excitation of surface plasmon polaritons with propagation and confinement lengths that can be actively controlled. This control is achieved by acting on the free carrier density, which can be realized by changing the temperature of InSb.

  20. Crystallization of amorphous silicon thin films using nanoenergetic intermolecular materials with buffer layers

    Science.gov (United States)

    Lee, Choong Hee; Jeong, Tae Hoon; Kim, Do Kyung; Jeong, Woong Hee; Kang, Myung-Koo; Hwang, Tae Hyung; Kim, Hyun Jae

    2009-02-01

    Optimization of the crystallization of amorphous silicon (a-Si) using a mixture of nanoenergetic materials of iron oxide/aluminum (Fe 2O 3/Al) was studied. To achieve high-quality polycrystalline Si (poly-Si) thin films, silicon oxide (SiO 2) and silver (Ag) layer were deposited on the a-Si as buffer layers to prevent the metal diffusion in a-Si during thermite reaction and to transport the thermal energy released from nanoenergetic materials, respectively. Raman measurement was used to define the crystallinity of poly-Si. For molar ratio of Al and Fe of 2 with 100-nm-thick-SiO 2, Raman measurement showed the 519.59 cm -1 of peak position and the 5.08 cm -1 of full width at half maximum with 353 MPa of low tensile stress indicating high quality poly-Si thin film. These results showed that optimized thermite reaction could be used successfully in crystallization of a-Si to high -quality poly-Si thin films.

  1. Transient Response of Thin Wire above a Layered Half-Space Using TDIE/FDTD Hybrid Method

    Directory of Open Access Journals (Sweden)

    Bing Wei

    2012-01-01

    Full Text Available The TDIE/FDTD hybrid method is applied to calculate the transient responses of thin wire above a lossy layered half-space. The time-domain reflection of the layered half space is computed by one-dimensional modified FDTD method. Then, transient response of thin wire induced by two excitation sources (the incident wave and reflected wave is calculated by TDIE method. Finally numerical results are given to illustrate the feasibility and high efficiency of the presented scheme.

  2. Separation of Caffeine from Beverages and Analysis Using Thin-Layer Chromatography and Gas Chromatography-Mass Spectrometry

    Science.gov (United States)

    Torres y Torres, Janelle L.; Hiley, Shauna L.; Lorimor, Steven P.; Rhoad, Jonathan S.; Caldwell, Benjamin D.; Zweerink, Gerald L.; Ducey, Michael

    2015-01-01

    The Characterization and Analysis of a Product (CAP) project is used to introduce first-semester general chemistry students to chemical instrumentation through the analysis of caffeine-containing beverage products. Some examples of these products have included coffee, tea, and energy drinks. Students perform at least three instrumental experiments…

  3. DETERMINATION OF NATURAL COMPOUNDS IN DASHMOOL EXTRACTS BY THIN LAYER CHROMATOGRAPHY AND HIGH-PRESSURE LIQUID CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Mittal Sandhya

    2012-12-01

    Full Text Available The determination of the natural compounds lupeol, beta sitosterol and stigmasterol in plant extracts using HPLC Shimadzu Model LC2010 AHT Auto Sampler (UV –VIS Detector is reported. The methods were applied to the analysis of lupeol, beta sitosterol and stigmasterol in petroleum ether extract originating from Dashmool. The result of TLC of Dashmool petroleum ether extract showed the presence of β- sitosterol, stigmasterol and lupeol in Dashmool plant extract at different Rf. HPLC profile of petroleum ether extract of Dashmool have characteristics peaks at retention time 2.888, 2.971, 3.135, 3.442, 4.018, 4.220, 4.406, 4.885, 5.388, 5.657, 6.083 (Stigmasterol, 7.848, 9.137, 10.012, 17.656 (Lupeol, 18.138 (β-Sitosterol and 23.096. These peaks showed that there are different compounds and characteristic fingerprints of drug to judge in a herbal formulation.

  4. A large-deformation thin plate theory with application to one-atom-thick layers

    Science.gov (United States)

    Delfani, M. R.; Shodja, H. M.

    2016-02-01

    Nowadays, two-dimensional materials due to their vast engineering and biomedical applications have been the focus of many researches. The present paper proposes a large-deformation theory for thin plates with application to one-atom-thick layers (OATLs). The deformation is formulated exactly in the mathematical framework of Lagrangian description. In particular, an exact finite strain analysis is given - in addition to the usual strain tensor associated to the middle surface, the second and third fundamental forms of the middle surface of the deformed thin plate are also maintained in the analysis. Exact closed-form solutions for a uniaxially curved thin plate due to pure bending in one case and due to a combination of vertical and horizontal loading in another are obtained. As a special case of the latter problem, the exact solution for the plane-strain bulge test of thin plates is derived. Subsequently, the approximation of Vlassak and Nix [Vlassak, J.J., Nix, W.D., 1992. J. Mater. Res., 7(12), 3242-3249] for the load-deflection equation is recovered. The given numerical results are devoted to graphene as the most well-known OATL.

  5. Transient grating studies of femtosecond processes in ultra-thin layers of PTCDA.

    Science.gov (United States)

    Karki, Khadga; Helms, Gesa; Namboodiri, Mahesh; Wagner, Veit; Fritz, Jürgen; Materny, Arnulf

    2012-02-01

    Elementary processes like energy transfer, charge transport, and exciton diffusion in thin films occur on time scales of femtoseconds. Time-resolved photo-electron spectroscopy, a technique limited to ultra-high vacuum environment and the proper choice of a substrate, has been used to study ultrafast processes in sub-nanometer thin films so far. Herein we show that a transient (population) grating created by the interference of laser pulses can be used to study ultrafast processes in such films under ambient conditions. Our investigations of exciton dynamics in 1.4±0.2 nm and 0.4±0.2 nm thin films, formed by nanocrystals of 3,4,9,10-Perylenetetracarboxylic dianhydride (PTCDA) on glass and mica, show that the dynamics differ with the crystal size, possibly due to the confinement induced changes in the electronic structure. The technique is sensitive enough to investigate the dynamics in systems, where only 20 % of the surface is covered by nano-crystals. We expect such an optical technique that is sensitive enough to study dynamics in few to sub-nanometer thin layers under ambient conditions to become important in investigating ultrafast dynamics on surfaces, interfaces, functionalized materials, organic semiconductors, and quantum phenomena in ordered structures of reduced dimensions, such as quantum dots and graphene sheets. PMID:22190482

  6. Experimental evidence of tunable space-charge-layer-induced electrical properties of nanocrystalline ceria thin films.

    Science.gov (United States)

    Lee, Kyung-Ryul; Lee, Jong-Ho; Yoo, Han-Ill

    2013-10-01

    Fully dense nanocrystalline ceria films were successfully deposited on a MgO single crystal by pulsed laser deposition (PLD). The electrical conductivity of the nanocrystalline thin film was 20 times higher than that of the bulk sample. The activation energy of bulk ceria was 2.3 eV, whereas the activation energy of the nanocrystalline sample was only 1.2 eV. After post-annealing at 1273 K in which the grain size of the nanocrystalline thin film increased to ~400 nm, the electrical conductivity and activation energy of the film were changed similar to those of bulk. These unique electrical properties of the nano-crystalline thin-film can be attributed to the grain size effect, or more specifically, to the space charge layer (SCL) effect. Furthermore, the electrical conductivity of the nanocrystalline thin film became similar to that of the bulk in an extremely reducing atmosphere because of the unusual dependence of the SCL effect on the oxygen partial pressure. PMID:23942424

  7. Visible light dynamical diffraction in a 1-D photonic crystal-based interferometer with an extremely thin spacer layer

    Science.gov (United States)

    Prudnikov, I. R.

    2016-01-01

    Properties of light diffraction in a Fabry-Pérot-like interferometer composed of two 1-D photonic crystals and a nanometer-thick spacer layer are analytically investigated. It is shown that the resonant enhancement of light wave intensity in such a layer is possible because of light dynamical diffraction from the photonic crystals of the interferometer. Numerical simulations of (i) light reflectivity and transmittance curves of the interferometer having an ultra-thin spacer layer (its thickness changes from less than 1 nm to about 10 nm) and (ii) the resonant distribution of the light wave intensity in the vicinity of the layer are performed. Based on the numerical simulations, potentialities for the determination of the structural parameters (e.g., thicknesses and refraction indexes) of ultra-thin spacer films are discussed. A difference is found to appear in resonant intensity enhancements inside the ultra-thin spacer layers between s- and p-polarized light waves.

  8. Thin and thick layers of resin-based sealer cement bonded to root dentine compared: Adhesive behaviour.

    Science.gov (United States)

    Pane, Epita S; Palamara, Joseph E A; Messer, Harold H

    2015-12-01

    This study aims to evaluate tensile and shear bond strengths of one epoxy (AH) and two methacrylate resin-based sealers (EZ and RS) in thin and thick layers bonded to root dentine. An alignment device was prepared for accurate positioning of 20 root dentine cylinders in a predefined gap of 0.1 or 1 mm. Sealer was placed in the interface. Bond strength tests were conducted. Mode of failures and representative surfaces were evaluated. Data were analysed using anova and post-hoc tests, with P layer of sealer produced higher bond strength, except for the shear bond strength of EZ. Significant differences between thin and thick layers were found only in tensile bond strengths of AH and RS. Mixed type of failure was constantly found with all sealers. Bond strengths of thick layers of resin-based sealers to root dentine tended to be higher than with thin layers.

  9. Preparation of bismuth telluride thin film by electrochemical atomic layer epitaxy(ECALE)

    Institute of Scientific and Technical Information of China (English)

    ZHU Wen; YANG Junyou; GAO Xianhui; HOU Jie; BAO Siqian; FAN Xian

    2007-01-01

    Thin-layer electrochemical studies of the underpotential deposition(UPD)of Bi and Te on cold rolled silver substrate have been performed.The voltammetric analysis of underpotential shift demonstrates that the initial Te UPD on Bi-covered Ag and Bi UPD on Te-covered Ag fitted UPD dynamics mechanism.A thin film of bismuth telluride was formed by alternately depositing Te and Bi via an automated flow deposition system.X-ray diffraction indicated the deposits of Bi2Te3.Energy Dispersive X-ray Detector quantitative analysis gave a 2:3 stoichiornetric ratio of Bi to Te,which was consistent with X-ray Diffraction results.Electron probe microanalysis of the deposits showed a network structure that results from the surface defects of the cold rolled Ag substrate and the lattice mismatch between substrate and deposit.

  10. Role of interfacial friction for flow instabilities in a thin polar-ordered active fluid layer

    Science.gov (United States)

    Sarkar, Niladri; Basu, Abhik

    2015-11-01

    We construct a generic coarse-grained dynamics of a thin inflexible planar layer of polar-ordered suspension of active particles that is frictionally coupled to an embedding isotropic passive fluid medium with a friction coefficient Γ . Being controlled by Γ , our model provides a unified framework to describe the long-wavelength behavior of a variety of thin polar-ordered systems, ranging from wet to dry active matter and free-standing active films. Investigations of the linear instabilities around a chosen orientationally ordered uniform reference state reveal generic moving and static instabilities in the system that can depend sensitively on Γ . Based on our results, we discuss estimation of bounds on Γ in experimentally accessible systems.

  11. Estimation of porosity in thin-layered reservoirs by seismic inversion

    Energy Technology Data Exchange (ETDEWEB)

    He, Nanqun; Reynolds, A.C. [Univ. of Tulsa, OK (United States)

    1995-12-31

    An effective method is presented to determine porosity distributions from seismic data for cases where the reservoir layers are thin. Porosity is determined by solving the inverse problem using a constrained generalized linear inversion (GLI) procedure. The inversion procedure estimates porosities directly rather than inverting for acoustic impedance or velocities and then estimating porosities. It is shown that sensitivity coefficients for porosity, i.e., the derivative of amplitudes with respect to porosity, can be computed analytically. Artificial interfaces are used to reduce non-uniquiness caused by lack of knowledge of thin bed reflection times. The artificial interfaces are generated by integration of seismic with log data. By using the artificial interfaces, the number of parameters to be estimated can be reduced and known formation information can be added as constraints. Inversion is done on only the seismic record associated with the reservoir instead of the whole seismic record.

  12. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    Directory of Open Access Journals (Sweden)

    Wang Lan

    2016-01-01

    Full Text Available We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

  13. Growth of α-sexithiophene nanostructures on C60 thin film layers

    International Nuclear Information System (INIS)

    Organic molecular beam grown α-sexithiophene (α-6T) forms nanostructured thin films on buckminsterfullerene (C60) thin film layers. At substrate temperatures of 300 K during growth a rough continuous film is observed, which develops to larger elongated islands and dendritic- as well as needle-like structures at temperatures around 390 K. X-ray diffractrometry reveals (100) crystalline orientation in the films grown at higher surface temperatures, which corresponds to upright oriented molecules. Rocking curves reveal the lowest mosaicity for samples grown at the highest substrate temperatures. From fluorescence polarimetry measurements the in-plane orientation within the needle like structures is determined. The polarimetry investigations together with the intensity of the fluorescence strongly indicate that the needle like structures consist of lying molecules. - Highlights: • Growth of α-sexithiophene nanostructures on buckminsterfullerene • X-ray spectrometry analysis of fabricated structures • Fluorescence polarimetry analysis of α-sexithiophene needle like structures

  14. Laser Structuring of Thin Layers for Flexible Electronics by a Shock Wave-induced Delamination Process

    Science.gov (United States)

    Lorenz, Pierre; Ehrhardt, Martin; Zimmer, Klaus

    The defect-free laser-assisted structuring of thin films on flexible substrates is a challenge for laser methods. However, solving this problem exhibits an outstanding potential for a pioneering development of flexible electronics. Thereby, the laser-assisted delamination method has a great application potential. At the delamination process: the localized removal of the layer is induced by a shock wave which is produced by a laser ablation process on the rear side of the substrate. In this study, the thin-film patterning process is investigated for different polymer substrates dependent on the material and laser parameters using a KrF excimer laser. The resultant structures were studied by optical microscopy and white light interferometry (WLI). The delamination process was tested at different samples (indium tin oxide (ITO) on polyethylene terephthalate (PET), epoxy-based negative photoresist (SU8) on polyimide (PI) and indium tin oxide/copper indium gallium selenide/molybdenum (ITO/CIGS/Mo) on PI.

  15. Electroluminescence of organic light-emitting diodes with an ultra-thin layer of dopant

    Energy Technology Data Exchange (ETDEWEB)

    Li Weizhi [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Yu Junsheng [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)], E-mail: jsyu@uestc.edu.cn; Wang, Tao [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Jiang, Yadong [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)], E-mail: jiangyd@uestc.edu.cn; Wei, Bangxiong [State Key Lab of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2008-03-15

    Conventional fluorescent dyes, i.e., 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB), 5,12-dihydro-5,12-dimethylquino [2,3-b]acridine-7,14-dione (DMQA) and 5,6,11,12-tetraphenylnaphthacene (Rubrene), were used to investigate the performance of organic light-emitting diodes (OLEDs) based on indium tin oxide (ITO)/N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB)/tris-(8-hydroxyquinolate)-aluminum (Alq{sub 3})/MgAg. The dyes were either inserted into devices as an ultra-thin film at the NPB/Alq{sub 3} interface by sequential evaporation, or doped into the Alq{sub 3} emission layer by co-evaporation with the doping ratio about 2%. Electroluminescence (EL) spectra of devices indicated that concentration quenching effect (CQE) of the dye-dopant was slightly bigger in the former than in the latter, while the degrees of CQE for three dopants are in the order of DMQA > DCJTB > Rubrene suggested by the difference in EL spectra and performances of devices. In addition, EL process of device with an ultra-thin layer of dopant is dominated by direct carrier trapping (DCT) process due to almost no holes recombine with electrons in Alq{sub 3}-host layer.

  16. Surface acoustic wave characterization of optical sol-gel thin layers.

    Science.gov (United States)

    Fall, Dame; Compoint, François; Duquennoy, Marc; Piombini, Hervé; Ouaftouh, Mohammadi; Jenot, Frédéric; Piwakowski, Bogdan; Belleville, Philippe; Ambard, Chrystel

    2016-05-01

    Controlling the thin film deposition and mechanical properties of materials is a major challenge in several fields of application. We are more particularly interested in the characterization of optical thin layers produced using sol-gel processes to reduce laser-induced damage. The mechanical properties of these coatings must be known to control and maintain optimal performance under various solicitations during their lifetime. It is therefore necessary to have means of characterization adapted to the scale and nature of the deposited materials. In this context, the dispersion of ultrasonic surface waves induced by a micrometric layer was studied on an amorphous substrate (fused silica) coated with a layer of ormosil using a sol-gel process. Our ormosil material is a silica-PDMS mixture with a variable polydimethylsiloxane (PDMS) content. The design and implementation of Surface Acoustic Wave InterDigital Transducers (SAW-IDT) have enabled quasi-monochromatic Rayleigh-type SAW to be generated and the dispersion phenomenon to be studied over a wide frequency range. Young's modulus and Poisson's ratio of coatings were estimated using an inverse method.

  17. Prediction of transmittance spectra for transparent composite electrodes with ultra-thin metal layers

    International Nuclear Information System (INIS)

    Recent interest in indium-free transparent composite-electrodes (TCEs) has motivated theoretical and experimental efforts to better understand and enhance their electrical and optical properties. Various tools have been developed to calculate the optical transmittance of multilayer thin-film structures based on the transfer-matrix method. However, the factors that affect the accuracy of these calculations have not been investigated very much. In this study, two sets of TCEs, TiO2/Au/TiO2 and TiO2/Ag/TiO2, were fabricated to study the factors that affect the accuracy of transmittance predictions. We found that the predicted transmittance can deviate significantly from measured transmittance for TCEs that have ultra-thin plasmonic metal layers. The ultrathin metal layer in the TCE is typically discontinuous. When light interacts with the metallic islands in this discontinuous layer, localized surface plasmons are generated. This causes extra light absorption, which then leads to the actual transmittance being lower than the predicted transmittance

  18. Prediction of transmittance spectra for transparent composite electrodes with ultra-thin metal layers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Alford, T. L., E-mail: TA@asu.edu [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Khorasani, Arash Elhami [ON Semiconductor Corp., Phoenix, Arizona 85005 (United States); Theodore, N. D. [CHD-Fab, Freescale Semiconductor Inc., Tempe, Arizona 85224 (United States); Dhar, A. [Intel Corp., 2501 NW 229th Ave, Hillsboro, Oregon 97124 (United States)

    2015-11-28

    Recent interest in indium-free transparent composite-electrodes (TCEs) has motivated theoretical and experimental efforts to better understand and enhance their electrical and optical properties. Various tools have been developed to calculate the optical transmittance of multilayer thin-film structures based on the transfer-matrix method. However, the factors that affect the accuracy of these calculations have not been investigated very much. In this study, two sets of TCEs, TiO{sub 2}/Au/TiO{sub 2} and TiO{sub 2}/Ag/TiO{sub 2}, were fabricated to study the factors that affect the accuracy of transmittance predictions. We found that the predicted transmittance can deviate significantly from measured transmittance for TCEs that have ultra-thin plasmonic metal layers. The ultrathin metal layer in the TCE is typically discontinuous. When light interacts with the metallic islands in this discontinuous layer, localized surface plasmons are generated. This causes extra light absorption, which then leads to the actual transmittance being lower than the predicted transmittance.

  19. Prediction of transmittance spectra for transparent composite electrodes with ultra-thin metal layers

    Science.gov (United States)

    Zhao, Zhao; Khorasani, Arash Elhami; Theodore, N. D.; Dhar, A.; Alford, T. L.

    2015-11-01

    Recent interest in indium-free transparent composite-electrodes (TCEs) has motivated theoretical and experimental efforts to better understand and enhance their electrical and optical properties. Various tools have been developed to calculate the optical transmittance of multilayer thin-film structures based on the transfer-matrix method. However, the factors that affect the accuracy of these calculations have not been investigated very much. In this study, two sets of TCEs, TiO2/Au/TiO2 and TiO2/Ag/TiO2, were fabricated to study the factors that affect the accuracy of transmittance predictions. We found that the predicted transmittance can deviate significantly from measured transmittance for TCEs that have ultra-thin plasmonic metal layers. The ultrathin metal layer in the TCE is typically discontinuous. When light interacts with the metallic islands in this discontinuous layer, localized surface plasmons are generated. This causes extra light absorption, which then leads to the actual transmittance being lower than the predicted transmittance.

  20. Metal-Organic Framework Thin Films as Stationary Phases in Microfabricated Gas-Chromatography Columns.

    Energy Technology Data Exchange (ETDEWEB)

    Read, Douglas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sillerud, Colin Halliday [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    The overarching goal of this project is to integrate Sandia's microfabricated gas-chromatography ( GC) columns with a stationary phase material that is capable of retaining high-volatility chemicals and permanent gases. The successful integration of such a material with GCs would dramatically expand the repertoire of detectable compounds for Sandia's various microanalysis systems. One such promising class of candidate materials is metal-organic frameworks (MOFs). In this report we detail our methods for controlled deposition of HKUST-1 MOF stationary phases within GC columns. We demonstrate: the chromatographic separation of natural gas; a method for determining MOF film thickness from chromatography alone; and the first-reported GC x GC separation of natural gas -- in general -- let alone for two disparate MOF stationary phases. In addition we determine the fundamental thermodynamic constant for mass sorption, the partition coefficient, for HKUST-1 and several light hydrocarbons and select toxic industrial chemicals.