Photoresist laminate

DOEpatents

Andrade, A.D.; Galbraith, L.K.

1979-10-01

The disclosure relates to a laminated negative dry-film photoresist for the production of thick, as well as thin, patterns with vertical sidewalls. Uniform depthwise exposure in a photoresist layer is effected by the use of an ultraviolet filtering top layer.

Mathematical models and qualities of shredded Thai-style instant rice under a combined gas-fired infrared and air convection drying

NASA Astrophysics Data System (ADS)

Nachaisin, Mali; Teeta, Suminya; Deejing, Konlayut; Pharanat, Wanida

2017-09-01

Instant food is a product produced for convenience for consumer. Qualities are an important attribute of food materials reflecting consumer acceptance. The most problem of instant rice is casehardening during drying process resulted in the longer rehydration time. The objective of this research was to study the qualities of shredded Thai-style instant rice under a combined gas-fired infrared and air convection drying. Additionally, the mathematical models for gas-fired infrared assisted thin-layer drying of shredded Thai-style rice for traditional was investigated. The thin-layer drying of shredded Thai-style rice was carried out under gas-fired infrared intensities of 1000W/m2, air temperatures of 70°C and air velocities of 1 m/s. The drying occurred in the falling rate of drying period. The Page model was found to satisfactorily describe the drying behavior of shredded Thai-style rice, providing the highest R2 (0.997) and the lowest MBE and RMSE (0.01 and 0.18) respectively. A 9 point hedonic test showed in softness and color, but odor and overall acceptance were very similar.

Effect of drying conditions on drying kinetics and quality of aromatic Pandanus amaryllifolius leaves.

PubMed

Rayaguru, Kalpana; Routray, Winny

2010-12-01

Pandanus amaryllifolius is a plant with aromatic leaves, which impart the characteristic flavour of aromatic rice. The quality of aromatic Pandanus leaves dried at low temperature (35 °C) and low RH (27%) in a heat pump dryer was evaluated and compared with those obtained from hot air drying at 45 °C. Thin-layer drying kinetics has been studied for both the conditions. To determine the kinetic parameters, the drying data were fitted to various semi-theoretical models. The goodness of fit was determined using the coefficient of determination, reduced chi square, and root mean square error. Aroma, colour, and overall acceptability determination of fresh and dried leaves were made using sensory evaluation. Drying of leaves took place mainly under the falling-rate period. The Page equation was found to be best among the proposed models to describe the thin-layer drying of Pandanus leaves with higher coefficient of determination. The effective moisture diffusivity values were also determined. The effect of low RH was prominent during the initial drying when the product was moist. The effect of temperature was prominent in the later part of drying, which acted as a driving force for moisture diffusion and hence the total drying time was reduced. Retention of aromatic compound 2-acetyl-1-pyrroline content was more in low temperature dried samples with higher sensory scores.

Effect of Hot Water Blanching Time and Drying Temperature on the Thin Layer Drying Kinetics of and Anthocyanin Degradation in Black Carrot (Daucus carota L.) Shreds.

PubMed

Garba, Umar; Kaur, Sawinder; Gurumayum, Sushma; Rasane, Prasad

2015-09-01

This study was conducted to investigate the effect of blanching treatment (98 °C for 3 and 6 min) and air drying temperature of 40, 50 and 60 °C on the thin layer drying characteristics such as drying time, drying rate constant, effective moisture diffusivity and activation energy, as well as on anthocyanin content of black carrot shreds. It was observed that drying temperature affected the drying rate but blanching did not have an effect on drying time. Three thin layer drying models, i.e. Page, Lewis and Henderson-Pabis were evaluated. The goodness of these models was evaluated based on the coefficient of determination (R 2 ), root mean square error, reduced chi square (χ 2 ) and standard error. Page model showed the best fit to the drying data. The effective diffusivity ranges of 1.4·10 -9 to 2.6·10 -9 m 2 /s, 1.3·10 -9 to 2.1·10 -9 m 2 /s and 1.5·10 -9 to 2.2·10 -9 m 2 /s after 3 or 6 min of blanching and control samples respectively were calculated using Fick's second law. The activation energy of 37.5, 26.0 and 34.6 kJ/(mol·K) of the control samples and samples blanched for 3 or 6 min respectively was determined from the Arrhenius plot. The blanching treatment affected the anthocyanin content to a great extent. The anthocyanin content of (231.7±2.9) and (278.8±7.8) mg per 100 g was recorded in samples blanched for 3 and 6 min and then dried at 60 °C, and (153.0±4.3) and (247.0±5.5) mg per 100 g was recorded at 40 °C as compared to the control of (580.1±1.3) at 60 °C and (466.7±1.1) mg per 100 g at 40 °C.

Thin layer convective air drying of wild edible plant (Allium roseum) leaves: experimental kinetics, modeling and quality.

PubMed

Ben Haj Said, Leila; Najjaa, Hanen; Farhat, Abdelhamid; Neffati, Mohamed; Bellagha, Sihem

2015-06-01

The present study deals with the valorization of an edible spontaneous plant of the Tunisian arid areas: Allium roseum. This plant is traditionally used for therapeutic and culinary uses. Thin-layer drying behavior of Allium roseum leaves was investigated at 40, 50 and 60 °C drying air temperatures and 1 and l.5 m/s air velocity, in a convective dryer. The increase in air temperature significantly affected the moisture loss and reduced the drying time while air velocity was an insignificant factor during drying of Allium roseum leaves. Five models selected from the literature were found to satisfactorily describe drying kinetics of Allium roseum leaves for all tested drying conditions. Drying data were analyzed to obtain moisture diffusivity values. During the falling rate-drying period, moisture transfer from Allium roseum leaves was described by applying the Fick's diffusion model. Moisture diffusivity varied from 2.55 × 10(-12) to 8.83 × 10(-12) m(2)/s and increased with air temperature. Activation energy during convective drying was calculated using an exponential expression based on Arrhenius equation and ranged between 46.80 and 52.68 kJ/mol. All sulfur compounds detected in the fresh leaves were detected in the dried leaves. Convective air drying preserved the sulfur compounds potential formation.

Evaluation of the mass transfer process on thin layer drying of papaya seeds from the perspective of diffusive models

NASA Astrophysics Data System (ADS)

Dotto, Guilherme Luiz; Meili, Lucas; Tanabe, Eduardo Hiromitsu; Chielle, Daniel Padoin; Moreira, Marcos Flávio Pinto

2018-02-01

The mass transfer process that occurs in the thin layer drying of papaya seeds was studied under different conditions. The external mass transfer resistance and the dependence of effective diffusivity ( D EFF ) in relation to the moisture ratio ( \\overline{MR} ) and temperature ( T) were investigated from the perspective of diffusive models. It was verified that the effective diffusivity was affected by the moisture content and temperature. A new correlation was proposed for drying of papaya seeds in order to describe these influences. Regarding the use of diffusive models, the results showed that, at conditions of low drying rates ( T ≤ 70 °C), the external mass transfer resistance, as well as the dependence of the effective diffusivity with respect to the temperature and moisture content should be considered. At high drying rates ( T > 90 °C), the dependence of the effective diffusivity with respect to the temperature and moisture content can be neglected, but the external mass transfer resistance was still considerable in the range of air velocities used in this work.

Fluidized bed drying characteristics and modeling of ginger ( zingiber officinale) slices

NASA Astrophysics Data System (ADS)

Parlak, Nezaket

2015-08-01

In this study fluidized bed drying characteristics of ginger have been investigated. The effects of the fluidizing air temperature, velocity, humidity and bed height on the drying performance of ginger slices have been found. The experimental moisture loss data of ginger slices has been fitted to the eight thin layer drying models. Two-term model drying model has shown a better fit to the experimental data with R2 of 0.998 as compared to others.

Densitometric thin-layer chromatographic determination of aescin in a herbal medicinal product containing Aesculus and Vitis dry extracts.

PubMed

Apers, Sandra; Naessens, Tania; Pieters, Luc; Vlietinck, Arnold

2006-04-21

A thin-layer chromatographic (TLC) method is developed to analyze the total saponin content, also referred to as the aescin content, in a herbal medicinal product (HMP) containing two dry extracts in capsules. The capsules contain 250 mg of Aesculus hippocastanum dry extract, 120 mg of Vitis vinifera dry extract and 50mg of excipients. After a purification step using C(18) solid phase extraction (SPE) cartridges, the samples are analyzed on a silica-gel HPTLC plate with the upper layer of a mixture of acetic acid/water/butanol (10/40/50 v/v/v) as the mobile phase. Spots are visualized by spraying with anisaldehyde reagent and heating the plate for 5-10 min (100-105 degrees C) and measured at a wavelength of 535 nm. This method, applicable for the quality control and stability investigation of both the Aesculus dry extract and HMP capsules thereof containing Vitis dry extract in combination with the Aesculus dry extract, is validated according to the International Conference on Harmonization (ICH) guidelines. The proposed assay method is specific for aescin in the presence of Vitis dry extract and formulation excipients. Analysis of stressed samples in forced degradation tests proves the method to be applicable for stability evaluation. The standard aescin curve is linear (r > 0.99) over a concentration range of 0.16-0.80 microg/spot. Recovery from the HMP capsules is statistically equal to 100%. The precision of the method with respect to time and concentration is acceptable, with relative standard deviation (RSD) values of 1.28 and 1.49%, respectively.

Bi-layer Channel AZO/ZnO Thin Film Transistors Fabricated by Atomic Layer Deposition Technique

NASA Astrophysics Data System (ADS)

Li, Huijin; Han, Dedong; Liu, Liqiao; Dong, Junchen; Cui, Guodong; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2017-03-01

This letter demonstrates bi-layer channel Al-doped ZnO/ZnO thin film transistors (AZO/ZnO TFTs) via atomic layer deposition process at a relatively low temperature. The effects of annealing in oxygen atmosphere at different temperatures have also been investigated. The ALD bi-layer channel AZO/ZnO TFTs annealed in dry O2 at 300 °C exhibit a low leakage current of 2.5 × 10-13A, I on/ I off ratio of 1.4 × 107, subthreshold swing (SS) of 0.23 V/decade, and high transmittance. The enhanced performance obtained from the bi-layer channel AZO/ZnO TFT devices is explained by the inserted AZO front channel layer playing the role of the mobility booster.

Polygonal crack patterns by drying thin films under quasi-two-dimensional confinement

NASA Astrophysics Data System (ADS)

Ma, Xiaolei; Lowensohn, Janna; Burton, Justin

Cracks patterns such as T/Y junction cracks in dried mud are ubiquitous in nature. Although the conditions for cracking in solids is well-known, cracks in colloidal and granular systems are more complex. Here we report the formations of polygonal cracks by drying thin films of corn starch ( 10 μm in diameter) under quasi-2D confinement. We find there are two drying stages before the films are completely dried. Initially, a compaction front invades throughout the film. Then, a second drying stage ''percolates'' throughout the film with a characteristic branching pattern, leading to a dense packing of particles connected by liquid capillary bridges. Finally, polygonal cracks appear as the remaining liquid dries. The same drying kinetics occur for films with different thickness, h, except that fractal-like fracture patterns form in thin films, where the thickness is comparable to the particle size, while polygons form in thick films with many layers of particles. We also find that the average area of the polygons, A, in fully dried films scales with the thickness, A hβ , where β 1 . 5 , and the prefactor depends on the initial packing fraction of the suspension. This form is consistent with a simple energy balance criterion for crack formation.

Irradiation of industrial enzyme preparations. II. Characterization of fungal pectinase by thin-layer isoelectric focusing and gel filtration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delincee, H.

1978-01-01

Industrial dry fungal pectinase from A. niger was irradiated with doses (up to 1 Mrad) of /sup 60/Co-..gamma..rays effective in reducing microbial contamination. The pectinase was characterized by thin-layer isoelectric focusing and gel filtration in order to detect possible radiation-induced structural alterations. Thin-layer isoelectric focusing revealed at least fifteen multiple forms with pectin-depolymerizing activity, with isoelectric points in the range pH 4.5 to 7. Heterogeneity of pectinesterase was also demonstrated, the main band occurring around pH 4. By thin-layer gel filtration the molecular weight of the pectin-depolymerase was estimated as being about 36,000, and that of pectinesterase as about 33,000.more » Radiation-induced changes of the charge properties or molecular size of the irradiated pectinase preparation were not observed. The feasibility of using ionizing radiation for the reduction of microbial contamination of industrial enzyme preparations looks promising.« less

Defect-free ultrahigh flux asymmetric membranes

DOEpatents

Pinnau, Ingo; Koros, William J.

1990-01-01

Defect-free, ultrahigh flux integrally-skinned asymmetric membranes having extremely thin surface layers (<0.2 .mu.m) comprised of glassy polymers are disclosed. The membranes are formed by casting an appropriate drope followed by forced convective evaporation of solvent to obtain a dry phase separated asymmetrical structure. The structure is then washed in a precipitation liquid and dried.

Bi-layer Channel AZO/ZnO Thin Film Transistors Fabricated by Atomic Layer Deposition Technique.

PubMed

Li, Huijin; Han, Dedong; Liu, Liqiao; Dong, Junchen; Cui, Guodong; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2017-12-01

This letter demonstrates bi-layer channel Al-doped ZnO/ZnO thin film transistors (AZO/ZnO TFTs) via atomic layer deposition process at a relatively low temperature. The effects of annealing in oxygen atmosphere at different temperatures have also been investigated. The ALD bi-layer channel AZO/ZnO TFTs annealed in dry O 2 at 300 °C exhibit a low leakage current of 2.5 × 10 -13 A, I on /I off ratio of 1.4 × 10 7 , subthreshold swing (SS) of 0.23 V/decade, and high transmittance. The enhanced performance obtained from the bi-layer channel AZO/ZnO TFT devices is explained by the inserted AZO front channel layer playing the role of the mobility booster.

Ultrasonic shear wave couplant

DOEpatents

Kupperman, David S.; Lanham, Ronald N.

1985-01-01

Ultrasonically testing of an article at high temperatures is accomplished by the use of a compact layer of a dry ceramic powder as a couplant in a method which involves providing an ultrasonic transducer as a probe capable of transmitting shear waves, coupling the probe to the article through a thin compact layer of a dry ceramic powder, propagating a shear wave from the probe through the ceramic powder and into the article to develop echo signals, and analyzing the echo signals to determine at least one physical characteristic of the article.

Ultrasonic shear wave couplant

DOEpatents

Kupperman, D.S.; Lanham, R.N.

1984-04-11

Ultrasonically testing of an article at high temperatures is accomplished by the use of a compact layer of a dry ceramic powder as a couplant in a method which involves providing an ultrasonic transducer as a probe capable of transmitting shear waves, coupling the probe to the article through a thin compact layer of a dry ceramic powder, propagating a shear wave from the probe through the ceramic powder and into the article to develop echo signals, and analyzing the echo signals to determine at least one physical characteristic of the article.

Investigation of Selective Laser Melting Surface Alloyed Aluminium Metal Matrix Dispersive Reinforced Layers

NASA Astrophysics Data System (ADS)

Kamburov, V. V.; Dimitrova, R. B.; Kandeva, M. K.; Sofronov, Y. P.

2018-01-01

The aim of the paper is to investigate the improvement of mechanical properties and in particular wear resistance of laser surface alloyed dispersive reinforced thin layers produced by selective laser melting (SLM) technology. The wear resistance investigation of aluminium matrix composite layers in the conditions of dry friction surface with abrasive particles and nanoindentation tests were carried out. The process parameters (as scan speed) and their impact on the wear resistant layers have been evaluated. The alloyed layers containing metalized SiC particles were studied by Optical and Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray microanalysis (EDX). The obtained experimental results of the laser alloyed thin layers show significant development of their wear resistance and nanohardness due to the incorporated reinforced phase of electroless nickel coated SiC particles.

"Dry-column" chromatography of plant pigments

NASA Technical Reports Server (NTRS)

Woeller, F. H.; Lehwalt, M. F.; Oyama, V. I.

1973-01-01

Separation of plant pigments which can be accomplished on thin-layer silica plates with mixture of petroleum ether, halocarbon, acetone, and polar solvent can be readily translated into dry-column technique that yields reproducible chromatograms after elution in fashion of liquid chromatography with fluorimeter as detector. Best solvent system was found to be mixture of petroleum ether, dichloromethane, acetone, and ethyl acetate.

21 CFR 347.50 - Labeling of skin protectant drug products.

Code of Federal Regulations, 2010 CFR

2010-04-01

... states “dries the oozing and weeping of poison: [bullet] ivy [bullet] oak [bullet] sumac”. (4) For...) “When using this product [bullet] do not get into eyes”. (3) “Stop use and ask a doctor if [bullet... doctor [bullet] pat dry (do not rub) to keep a thin layer on the skin”. (B) For products used as a...

ELECTRON MICROSCOPIC OBSERVATION OF SPECIMENS UNDER CONTROLLED GAS PRESSURE

PubMed Central

Heide, Hans Gunther

1962-01-01

A technique for encasing specimens in a thin gas layer during their observation in the Siemens Elmiskop I is described. All gases can be employed at pressures up to one atmosphere. Destruction of specimens can occur in the beam; all organic specimens are particularly liable to decompose. The conditions under which this can be avoided are given. A useful application of the technique allows one to prevent specimens from drying out, as they normally do in vacuum. A further application uses the controlled removal of carbon for thinning organic layers and for selective etching of organic materials. PMID:13905967

Mathematical modelling of thin layer hot air drying of apricot with combined heat and power dryer.

PubMed

Faal, Saeed; Tavakoli, Teymor; Ghobadian, Barat

2015-05-01

In this study thermal energy of an engine was used to dry apricot. For this purpose, experiments were conducted on thin layer drying apricot with combined heat and power dryer, in a laboratory dryer. The drying experiments were carried out for four levels of engine output power (25 %, 50 %, 75 % and full load), producing temperatures of 50, 60, 70, and 80 ° C in drying chamber respectively. The air velocity in drying chamber was about 0.5 ± 0.05 m/s. Different mathematical models were evaluated to predict the behavior of apricot drying in a combined heat and power dryer. Conventional statistical equations namely modeling efficiency (EF), Root mean square error (RMSE) and chi-square (χ2) were also used to determine the most suitable model. Assessments indicated that the Logarithmic model considering the values of EF = 0.998746, χ 2 = 0.000120 and RMSE = 0.004772, shows the best treatment of drying apricot with combined heat and power dryer among eleven models were used in this study. The average values of effective diffusivity ranged 1.6260 × 10(-9) to 4.3612 × 10(-9) m2/s for drying apricot at air temperatures between 50 and 80 °C and at the air flow rate of 0.5 ± 0.05 m/s; the values of Deff increased with the increase of drying temperature the effective diffusivities in the second falling rate period were about eight times greater than that in the first falling rate period.

Dewetting and deposition of thin films with insoluble surfactants from curved silicone hydrogel substrates.

PubMed

Bhamla, M Saad; Balemans, Caroline; Fuller, Gerald G

2015-07-01

We investigate the stabilizing effect of insoluble surfactant monolayers on thin aqueous films. We first describe an experimental platform that enables the formation of aqueous films laden with dipalmitoylphosphatidylcholine (DPPC) monolayers on curved silicone hydrogel (SiHy) substrates. We show that these surfactant layers extend the lifetime of the aqueous films. The films eventually "dewet" by the nucleation and growth of dry areas and the onset of this dewetting can be controlled by the surface rheology of the DPPC layer. We thus demonstrate that increasing the interfacial rheology of the DPPC layer leads to stable films that delay dewetting. We also show that dewetting can be exploited to controllably pattern the underlying curved SiHy substrates with DPPC layers. Copyright © 2015 Elsevier Inc. All rights reserved.

Cumulative ventilation air drying potential as an indication of dry mass content in wastewater sludge in a thin-layer solar drying facility

NASA Astrophysics Data System (ADS)

Krawczyk, Piotr

2013-12-01

Controlling low-temperature drying facilities which utilise nonprepared air is quite difficult, due to very large variability of ventilation air parameters - both in daily and seasonal cycles. The paper defines the concept of cumulative drying potential of ventilation air and presents experimental evidence that there is a relation between this parameter and condition of the dried matter (sewage sludge). Knowledge on current dry mass content in the dried matter (sewage sludge) provides new possibilities for controlling such systems. Experimental data analysed in the paper was collected in early 2012 during operation of a test solar drying facility in a sewage treatment plant in Błonie near Warsaw, Poland.

Long-Wavelength Instability in Marangoni Convection

NASA Technical Reports Server (NTRS)

VanHook, Stephen J.; Schatz, Michael F.; Swift, Jack B.; McCormick, W. D.; Swinney, Harry L.

1996-01-01

Our experiments in thin liquid layers (approximately 0.1 mm thick) heated from below reveal a well-defined long-wavelength instability: at a critical temperature difference across the layer, the depth of the layer in the center of the cell spontaneously decreases until the liquid-air interface ruptures and a dry spot forms. The onset of this critical instability occurs at a temperature difference across the liquid layer that is 35% smaller than that predicted in earlier theoretical studies of a single layer model. Our analysis of a two-layer model yields predictions in accord with the observations for liquid layer depths greater than or equal to 0.15 mm, but for smaller depths there is an increasing difference between our predictions and observations (the difference is 25% for a layer 0.06 mm thick). In microgravity environments the long-wavelength instability observed in our terrestrial experiments is expected to replace cellular convection as the primary instability in thick as well as thin liquid layers heated quasistatically from below.

Evaluation on the air-borne ultrasound-assisted hot air convection thin-layer drying performance of municipal sewage sludge.

PubMed

Sun, G Y; Chen, M Q; Huang, Y W

2017-01-01

The thin-layer drying behavior of the municipal sewage sludge in a laboratory-scale hot air forced convective dryer assisted with air-borne ultrasound was investigated in between 70 and 130°C hot air temperatures. The drying kinetics in the convective process alone were compared to that for ultrasound-assist process at three ultrasound powers (30, 90, 150W). The average drying rates within whole drying temperature range at ultrasound powers of 30, 90 and 150W increased by about 22.6%, 27.8% and 32.2% compared with the convective drying alone (without ultrasound). As the temperature increasing from 70°C to 130°C, there were maximum increasing ratios for the effective moisture diffusivities of the sewage sludge in both falling rate periods at ultrasonic power of 30W in comparison with other two high powers. In between the ultrasound powers of 0 and 30W, the effect of the power on the drying rate was significant, while its effect was not obvious over 30W. Therefore, the low ultrasonic power can be just set in the drying process. The values of the apparent activation energy in the first falling rate period were down from 13.52 to 12.78kJmol -1 , and from 17.21 to 15.10kJmol -1 for the second falling rate period with increasing the ultrasonic power from 30 to 150W. The values of the apparent activation energy in two falling rate periods with the ultrasound-assist were less than that for the hot air convective drying alone. Copyright © 2016 Elsevier B.V. All rights reserved.

Mass transfer, physical, and mechanical characteristics of terebinth fruit (Pistacia atlantica L.) under convective infrared microwave drying

NASA Astrophysics Data System (ADS)

Kaveh, Mohammad; Abbaspour-Gilandeh, Yousef; Chayjan, Reza Amiri; Taghinezhad, Ebrahim; Mohammadigol, Reza

2018-01-01

This research was investigated to the thin-layer drying of terebinth fruit under convective infrared microwave (CIM) conditions with initial moisture content about 4.28% (g water/g dry matter). The effects of drying different conditions were studied on the effective moisture diffusivity, activation energy, specific energy, shrinkage, color, and mechanical properties of terebinth. Experiments were conducted at three air temperatures (45, 60, and 70 °C), three infrared power (500, 1000, and 1500 W) and three microwave power (270, 450 and 630 W). All these experiments were carried out under air velocity of 0.9 m/s. The effective moisture diffusivity of terebinth was obtained as 1.79 × 10-9 to 15.77 × 10-9 m2/s during drying. The activation energy of terebinth samples was measured to be 12.70 to 32.28 kJ/mol. To estimate the drying kinetic of terebinth, seven mathematical models were used to fit the experimental data of thin-layer drying. Results showed that the Midilli et al. model withR 2 = 0.9999, χ 2 = 0.0001 andRMSE = 0.0099 had the best performance in prediction of moisture content. Specific energy consumption was within the range of 127.62 to 678.90 MJ/kg. The maximum shrinkage during drying was calculated 69.88% at the air temperature 75 °C, infrared power of 1500 W, and microwave power 630 W. Moreover, the maximum values of the ΔL ∗ (15.89), Δa ∗ (12.28), Δb ∗(-0.12), and total color difference (ΔE= 17.44) were calculated in this work. Also, the maximum rupture force and energy for dried terebinth were calculated to be 149.2 N and 2845.4 N.mm, respectively.

Mass transfer, physical, and mechanical characteristics of terebinth fruit ( Pistacia atlantica L.) under convective infrared microwave drying

NASA Astrophysics Data System (ADS)

Kaveh, Mohammad; Abbaspour-Gilandeh, Yousef; Chayjan, Reza Amiri; Taghinezhad, Ebrahim; Mohammadigol, Reza

2018-07-01

This research was investigated to the thin-layer drying of terebinth fruit under convective infrared microwave (CIM) conditions with initial moisture content about 4.28% (g water/g dry matter). The effects of drying different conditions were studied on the effective moisture diffusivity, activation energy, specific energy, shrinkage, color, and mechanical properties of terebinth. Experiments were conducted at three air temperatures (45, 60, and 70 °C), three infrared power (500, 1000, and 1500 W) and three microwave power (270, 450 and 630 W). All these experiments were carried out under air velocity of 0.9 m/s. The effective moisture diffusivity of terebinth was obtained as 1.79 × 10-9 to 15.77 × 10-9 m2/s during drying. The activation energy of terebinth samples was measured to be 12.70 to 32.28 kJ/mol. To estimate the drying kinetic of terebinth, seven mathematical models were used to fit the experimental data of thin-layer drying. Results showed that the Midilli et al. model with R 2 = 0.9999, χ 2 = 0.0001 and RMSE = 0.0099 had the best performance in prediction of moisture content. Specific energy consumption was within the range of 127.62 to 678.90 MJ/kg. The maximum shrinkage during drying was calculated 69.88% at the air temperature 75 °C, infrared power of 1500 W, and microwave power 630 W. Moreover, the maximum values of the Δ L ∗ (15.89), Δ a ∗ (12.28), Δ b ∗(-0.12), and total color difference (Δ E= 17.44) were calculated in this work. Also, the maximum rupture force and energy for dried terebinth were calculated to be 149.2 N and 2845.4 N.mm, respectively.

Preparation and characterization of titania-deposited silica composite hollow fiber membranes with high hydrothermal stability.

PubMed

Kwon, Young-Nam; Kim, In-Chul

2013-11-01

Hydrothermal stability of a porous nickel-supported silica membrane was successfully improved by deposition of titania multilayers on colloidal silica particles embedded in the porous nickel fiber support. Porous nickel-supported silica membranes were prepared by means of a dipping-freezing-fast drying (DFF) method. The titania layers were deposited on colloidal silica particles by repeating hydrolysis and condensation reactions of titanium isopropoxide on the silica particle surfaces. The deposition of thin titania layers on the nickel-supported silica membrane was verified by various analytical tools. The water flux and the solute rejection of the porous Ni fiber-supported silica membranes did not change after titania layer deposition, indicating that thickness of titania layers deposited on silica surface is enough thin not to affect the membrane performance. Moreover, improvement of the hydrothermal stability in the titania-deposited silica membranes was confirmed by stability tests, indicating that thin titania layers deposited on silica surface played an important role as a diffusion barrier against 90 degrees C water into silica particles.

Method of fabrication of electrodes and electrolytes

DOEpatents

Jankowski, Alan F.; Morse, Jeffrey D.

2004-01-06

Fuel cell stacks contain an electrolyte layer surrounded on top and bottom by an electrode layer. Porous electrodes are prepared which enable fuel and oxidant to easily flow to the respective electrode-electrolyte interface without the need for high temperatures or pressures to assist the flow. Rigid, inert microspheres in combination with thin-film metal deposition techniques are used to fabricate porous anodes, cathodes, and electrolytes. Microshperes contained in a liquid are randomly dispersed onto a host structure and dried such that the microsperes remain in position. A thin-film deposition technique is subsequently employed to deposit a metal layer onto the microsperes. After such metal layer deposition, the microspheres are removed leaving voids, i.e. pores, in the metal layer, thus forming a porous electrode. Successive repetitions of the fabrication process result in the formation of a continuous fuel cell stack. Such stacks may produce power outputs ranging from about 0.1 Watt to about 50 Watts.

Controlling the crack formation in inkjet-printed silver nanoparticle thin-films for high resolution patterning using intense pulsed light treatment

NASA Astrophysics Data System (ADS)

Gokhale, Pritesh; Mitra, Dana; Sowade, Enrico; Yoti Mitra, Kalyan; Leonel Gomes, Henrique; Ramon, Eloi; Al-Hamry, Ammar; Kanoun, Olfa; Baumann, Reinhard R.

2017-12-01

During the last years, intense pulsed light (IPL) processing has been employed and studied intensively for the drying and sintering of metal nanoparticle layers deposited by means of printing methods on flexible polymer substrates. IPL was found to be a very fast and substrate-gentle approach qualified for the field of flexible and large-area printed electronics, i.e. manufactured via roll-to-roll processing. In this contribution, IPL is used for the fine-patterning of printed silver nanoparticle layers. The patterning is obtained by induced and controlled crack formation in the thin silver layer due to the intense exposure of IPL. The crack formation is controlled by selection of the substrate material, the fine-tuning of the morphology of the silver layer and an application of a dielectric layer on top of the silver layer that acts as a stress concentrator. Careful optimization of the IPL parameters allowed to adjust the lateral width of the crack. This novel approach turned out to be a fast and reproducible high-resolution patterning process for multiple applications, e.g. to pattern the source-drain electrodes for all-inkjet-printed thin-film transistors.

Modelling of nectarine drying under near infrared - Vacuum conditions.

PubMed

Alaei, Behnam; Chayjan, Reza Amiri

2015-01-01

Drying of nectarine slices was performed to determine the thermal and physical properties in order to reduce product deterioration due to chemical reactions, facilitate storage and lower transportation costs. Because nectarine slices are sensitive to heat with long drying period, the selection of a suitable drying approach is a challenging task. Infrared-vacuum drying can be used as an appropriate method for susceptible materials with high moisture content such as nectarine slices. Modelling of nectarine slices drying was carried out in a thin layer near infraredvacuum conditions. Drying of the samples was implemented at the absolute pressures of 20, 40 and 60 kPa and drying temperatures of 50, 60 and 70°C. Drying behaviour of nectarine slices, as well as the effect of drying conditions on moisture loss trend, drying rate, effective diffusion coefficient, activation energy, shrinkage, colour and energy consumption of nectarine slices, dried in near infrared-vacuum dryer are discussed in this study. Six mathematical models were used to predict the moisture ratio of the samples in thin layer drying. The Midilli model had supremacy in prediction of nectarine slices drying behaviour. The maximum drying rates of the samples were between 0.014-0.047 gwater/gdry material·min. Effective moisture diffusivity of the samples was estimated in the ranges of 2.46·10-10 to 6.48·10-10 m2/s. Activation energy were computed between 31.28 and 35.23 kJ/mol. Minimum shrinkage (48.4%) and total colour difference (15.1) were achieved at temperature of 50°C and absolute pressure of 20 kPa. Energy consumption of the tests was estimated in the ranges of 0.129 to 0.247 kWh. Effective moisture diffusivity was increased with decrease of vacuum pressure and increase of drying temperature but effect of drying temperature on effective moisture diffusivity of nectarine slices was more than vacuum pressure. Activation energy was decreased with decrease in absolute pressure. Total colour difference and shrinkage of nectarine slices on near infrared-vacuum drying was decreased with decrease of vacuum pressure and decrease of drying temperature.

Optical interference probe of biofilm hydrology: label-free characterization of the dynamic hydration behavior of native biofilms

NASA Astrophysics Data System (ADS)

McDonough, Richard T.; Zheng, Hewen; Alila, Mercy A.; Goodisman, Jerry; Chaiken, Joseph

2017-03-01

Biofilm produced by Escherichia coli (E. coli) or Pseudomonas aeruginosa (P. aeruginosa) on quartz or polystyrene is removed from the culture medium and drained. Observed optical interference fringes indicate the presence of a layer of uniform thickness with refractive index different from air-dried biofilm. Fringe wavelengths indicate that layer optical thickness is <20 μm or 1 to 2 orders of magnitude thinner than the biofilm as measured by confocal Raman microscopy or fluorescence imaging of the bacteria. Raman shows that films have an alginate-like carbohydrate composition. Fringe amplitudes indicate that the refractive index of the interfering layer is higher than dry alginate. Drying and rehydration nondestructively thins and restores the interfering layer. The strength of the 1451-nm near infrared water absorption varies in unison with thickness. Absorption and layer thickness are proportional for films with different bacteria, substrates, and growth conditions. Formation of the interfering layer is general, possibly depending more on the chemical nature of alginate-like materials than bacterial processes. Films grown during the exponential growth phase produce no observable interference fringes, indicating requirements for layer formation are not met, possibly reflecting bacterial activities at that stage. The interfering layer might provide a protective environment for bacteria when water is scarce.

Development of a compact freeze vacuum drying for jelly fish (Schypomedusae)

NASA Astrophysics Data System (ADS)

Alhamid, M. Idrus; Yulianto, M.; Nasruddin

2012-06-01

A new design of a freeze vacuum drying with internal cooling and heater from condenser's heat loss was built and tested. The dryer was used to dry jelly fish (schypomedusae), to study the effect of drying parameters such as the temperature within the drying chamber on mass losses (evaporation) during the freezing stage and the moisture ratio at the end of the drying process. The midili thin layer mathematical drying model was used to estimate and predict the moisture ratio curve based on different drying chamber temperatures. This experiment shows that decreasing the drying chamber temperature with constant pressure results in less mass loss during the freezing stage Drying time was reduced with an increase in drying temperature. Decreasing the drying chamber temperature results in lower pressure saturation of the material has no effect of drying chamber pressure on mass transfer.

Influence of Si wafer thinning processes on (sub)surface defects

NASA Astrophysics Data System (ADS)

Inoue, Fumihiro; Jourdain, Anne; Peng, Lan; Phommahaxay, Alain; De Vos, Joeri; Rebibis, Kenneth June; Miller, Andy; Sleeckx, Erik; Beyne, Eric; Uedono, Akira

2017-05-01

Wafer-to-wafer three-dimensional (3D) integration with minimal Si thickness can produce interacting multiple devices with significantly scaled vertical interconnections. Realizing such a thin 3D structure, however, depends critically on the surface and subsurface of the remaining backside Si after the thinning processes. The Si (sub)surface after mechanical grinding has already been characterized fruitfully for a range of few dozen of μm. Here, we expand the characterization of Si (sub)surface to 5 μm thickness after thinning process on dielectric bonded wafers. The subsurface defects and damage layer were investigated after grinding, chemical mechanical polishing (CMP), wet etching and plasma dry etching. The (sub)surface defects were characterized using transmission microscopy, atomic force microscopy, and positron annihilation spectroscopy. Although grinding provides the fastest removal rate of Si, the surface roughness was not compatible with subsequent processing. Furthermore, mechanical damage such as dislocations and amorphous Si cannot be reduced regardless of Si thickness and thin wafer handling systems. The CMP after grinding showed excellent performance to remove this grinding damage, even though the removal amount is 1 μm. For the case of Si thinning towards 5 μm using grinding and CMP, the (sub)surface is atomic scale of roughness without vacancy. For the case of grinding + dry etch, vacancy defects were detected in subsurface around 0.5-2 μm. The finished surface after wet etch remains in the nm scale in the strain region. By inserting a CMP step in between grinding and dry etch it is possible to significantly reduce not only the roughness, but also the remaining vacancies at the subsurface. The surface of grinding + CMP + dry etching gives an equivalent mono vacancy result as to that of grinding + CMP. This combination of thinning processes allows development of extremely thin 3D integration devices with minimal roughness and vacancy surface.

Particle-based Nano-Antennas at the Vis-NIR regime

DTIC Science & Technology

2013-11-01

PSS (poly(3,4-ethylenedioxythiophene) :poly(styrene sulfonate) is then spin coated and dried at 110oC to form a 50nm buffer layer partially covering...dominant effect is that during the spin coating of the 50nm PEDOT buffer a residual very thin layer coated also the top 50nm part of the Au disks...antennas, capacitive versus conductive coupling, on-demand design (termed ‘popcorn’ antennas), broadband plasmonic metamaterials, and light

Directional optical transmission through a sand layer: a preliminary laboratory experiment

NASA Astrophysics Data System (ADS)

Tian, Jia; Philpot, William D.

2017-10-01

Given the importance of penetration of light in the soil for seed germination, soil warming, and the photolytic degradation of pesticides, directional transmission of thin sand samples are studied in this paper under both dry and saturated conditions. The detector views upward through a glass-bottom sample holder, filled to 3 or 4 mm with a coarse, translucent, quartz sand sample. Transmission through the samples was measured as the illumination zenith angle moved from 0 to 70° in 5° intervals. In the most cases, transmission decreased monotonically, but slowly with increasing illumination angle at all wavelengths. A peak in transmission only appeared at 0° illumination for the low bulk density, dry sample at 3 mm depth. The 0° peak disappeared when the sample was wetted, when the bulk density increased, or when the depth of the sample increased, which indicates that the radiation transmitting through a sand layer can be diffused thoroughly with a millimeters-thin sand layer. For the saturated samples, water influences light transmission in contrasting ways in shorter and longer wavelength. Transmission increased in the VNIR when saturated relative to dry, while transmission decreased sharply after 1300 nm, with spectral absorption features characteristic of water absorption. In VNIR region, water absorption is low and the low relative index of refraction enhanced transmission through sand sample. In contrast, water absorption became dominant at longer wavelengths region leading to the strongly reduced transmission.

Optimization of the Automated Spray Layer-by-Layer Technique for Thin Film Deposition

DTIC Science & Technology

2010-06-01

pieces. All silicon was cleaned with ethanol and Milli-Q water to hydroxylate the surface. Quartz Crystal Microbalance Si02 coated sensors (Q-sense...was deposited onto a SiO2 coated QCM crystal using the automated dipping process described earlier. Once the film was deposited, it was dried over...night, and then placed in the QCM -D device. An additional layer of PAH was deposited onto the crystal in the QCM -D chamber at a flow rate of 1pL/minute

Studies on convective drying of `Ameclyae' Opuntia ficus-indica seeds and its effect on the quality of extracted oil based on its α-tocopherol content

NASA Astrophysics Data System (ADS)

Hassini, Lamine; Bettaieb, Emna; Motri, Samia; Desmorieux, Hélène

2018-02-01

The aim of this work is to model the thin layer convective drying kinetics of `Ameclyae' prickly pear seed variety and to evaluate the effects of drying conditions on the quality of extracted seed oil, specifically α-tocopherol content. Drying experiments were carried on following a full 23 factorial design using a vertical drying tunnel. The study is restricted to a particular particle size and a particular seed bed of height 0.5 cm, of effective porosity around 0.4 and of initial moisture content on dry basis equal to 1.2 (± 0.01) kg/kg. The temperature range was 45 to 70 °C, relative humidity range was 15-30% and air velocity was 1 and 2 m/s. The experimental drying curves were fitted to different semi-theoretical drying models proposed in the literature. The Midilli-Kucuk model was found with satisfaction describing the seed air drying curves with a correlation coefficient of 0.999 and a standard error of 0.01. For each drying condition, the extraction of fixed oil seeds was performed at cold using liquid/solid separation method. The oil quality was evaluated on the basis of the α-tocopherol content. The α-tocopherol was identified and quantified by high-performance liquid chromatography (HPLC-UV). According to the experimental results, it was found that drying air velocity is the most important factor influencing the concentration of α-tocopherol, whereas the effects of temperature and relative humidity were lower. The increase of the velocity from 1 m/s to 2 m/s reduced the α-tocopherol concentration by about 25%. The convective drying of thin layer of seeds at soft air conditions, drying temperature of 45 °C, relative humidity of 15% and air velocity of 1 m/s give the optimal quality of extracted oil in terms of α-tocopherol content. Characterization of the morphologic structure of seeds was also performed by SEM.

A thermal microprobe fabricated with wafer-stage processing

NASA Astrophysics Data System (ADS)

Zhang, Yongxia; Zhang, Yanwei; Blaser, Juliana; Sriram, T. S.; Enver, Ahsan; Marcus, R. B.

1998-05-01

A thermal microprobe has been designed and built for high resolution temperature sensing. The thermal sensor is a thin-film thermocouple junction at the tip of an atomic force microprobe (AFM) silicon probe needle. Only wafer-stage processing steps are used for the fabrication. For high resolution temperature sensing it is essential that the junction be confined to a short distance at the AFM tip. This confinement is achieved by a controlled photoresist coating process. Experiment prototypes have been made with an Au/Pd junction confined to within 0.5 μm of the tip, with the two metals separated elsewhere by a thin insulating oxide layer. Processing begins with double-polished, n-type, 4 in. diameter, 300-μm-thick silicon wafers. Atomically sharp probe tips are formed by a combination of dry and wet chemical etching, and oxidation sharpening. The metal layers are sputtering deposited and the cantilevers are released by a combination of KOH and dry etching. A resistively heated calibration device was made for temperature calibration of the thermal microprobe over the temperature range 25-110 °C. Over this range the thermal outputs of two microprobes are 4.5 and 5.6 μV/K and is linear. Thermal and topographical images are also obtained from a heated tungsten thin film fuse.

Drying Characteristics and Water-soluble Polysaccharides Evaluation of Kidney Shape Ganoderma lucidum Drying in Air Circulation System

NASA Astrophysics Data System (ADS)

Prasetyo, D. J.; Jatmiko, T. H.; Poeloengasih, C. D.; Kismurtono, M.

2017-12-01

In this project, drying kinetic of kidney shape Ganoderma lucidum fruiting body in air circulation system was studied. The drying experiments were conducted at 40, 50 and 60°C with air flow rate of 1.3 ms-1. Samples were weighted periodically until no change in sample weight was recorded, and then the samples were analyzed for its moisture content. Four different thin-layer mathematical models (Newton, Page, Two-term, Midilli) were used and compare to evaluate the drying curves of kidney shape G. lucidum. The water-soluble polysaccharides were evaluated in order to find the best drying temperature condition. The results indicates that Midilli model was the fittest model to describe the characteristic of kidney shape G. lucidum in the air circulation drying system and temperature of 50°C was the best drying condition to get highest value of water-soluble polysaccharides.

[Investigation on Spray Drying Technology of Auricularia auricular Extract].

PubMed

Zhou, Rong; Chen, Hui; Xie, Yuan; Chen, Peng; Wang, Luo-lin

2015-07-01

To investigate the feasibility of spray drying technology of Auricularia auricular extract and its optimum process. On the basis of single factor test, with the yield of dry extract and the content of polysaccharide as indexes, orthogonal test method was used to optimize the spray drying technology on the inlet air temperature, injection speed and crude drug content. Using ultraviolet spectrophotometry, thin layer chromatography(TLC) and pharmacodynamics as indicators, extracts prepared by traditional alcohol precipitation drying process and spray drying process were compared. Compared with the traditional preparation method, the extract prepared by spray drying had little differences from the polysaccharide content, TLC and the function of reducing TG and TC, and its optimum technology condition were as follows: The inlet air temperature was 180 °C, injection speed was 10 ml/min and crude drugs content was 0. 4 g/mL. Auricularia auricular extract by spray drying technology is stable and feasible with high economic benefit.

Dry texturing of solar cells

DOEpatents

Sopori, B.L.

1994-10-25

A textured backside of a semiconductor device for increasing light scattering and absorption in a semiconductor substrate is accomplished by applying infrared radiation to the front side of a semiconductor substrate that has a metal layer deposited on its backside in a time-energy profile that first produces pits in the backside surface and then produces a thin, highly reflective, low resistivity, epitaxial alloy layer over the entire area of the interface between the semiconductor substrate and a metal contact layer. The time-energy profile includes ramping up to a first energy level and holding for a period of time to create the desired pit size and density and then rapidly increasing the energy to a second level in which the entire interface area is melted and alloyed quickly. After holding the second energy level for a sufficient time to develop the thin alloy layer over the entire interface area, the energy is ramped down to allow epitaxial crystal growth in the alloy layer. The result is a textured backside on an optically reflective, low resistivity alloy interface between the semiconductor substrate and the metal electrical contact layer. 9 figs.

Dry texturing of solar cells

DOEpatents

Sopori, Bhushan L.

1994-01-01

A textured backside of a semiconductor device for increasing light scattering and absorption in a semiconductor substrate is accomplished by applying infrared radiation to the front side of a semiconductor substrate that has a metal layer deposited on its backside in a time-energy profile that first produces pits in the backside surface and then produces a thin, highly reflective, low resistivity, epitaxial alloy layer over the entire area of the interface between the semiconductor substrate and a metal contact layer. The time-energy profile includes ramping up to a first energy level and holding for a period of time to create the desired pit size and density and then rapidly increasing the energy to a second level in which the entire interface area is melted and alloyed quickly. After holding the second energy level for a sufficient time to develop the thin alloy layer over the entire interface area, the energy is ramped down to allow epitaxial crystal growth in the alloy layer. The result is a textured backside an optically reflective, low resistivity alloy interface between the semiconductor substrate and the metal electrical contact layer.

Investigation of drying kinetics of tomato slices dried by using a closed loop heat pump dryer

NASA Astrophysics Data System (ADS)

Coşkun, Salih; Doymaz, İbrahim; Tunçkal, Cüneyt; Erdoğan, Seçil

2017-06-01

In this study, tomato slices were dried at three different drying air temperatures (35, 40 and 45 °C) and at 1 m/s air velocities by using a closed loop heat pump dryer (HPD). To explain the drying characteristics of tomato slices, ten thin-layer drying models were applied. The drying of tomato slices at each temperature occurred in falling-rate period; no constant-rate period of drying was observed. The drying rate was significantly influenced by drying temperature. The effective moisture diffusivity varied between 8.28 × 10-11 and 1.41 × 10-10 m2/s, the activation energy was found to be 43.12 kJ/mol. Besides, at the end of drying process, the highest mean specific moisture extraction ratio and coefficient of performance of HPD system were obtained as 0.324 kg/kWh and 2.71, respectively, at the highest drying air temperature (45 °C).

Endolithic microbial life in extreme cold climate: snow is required, but perhaps less is more.

PubMed

Sun, Henry J

2013-04-03

Cyanobacteria and lichens living under sandstone surfaces in the McMurdo Dry Valleys require snow for moisture. Snow accumulated beyond a thin layer, however, is counterproductive, interfering with rock insolation, snow melting, and photosynthetic access to light. With this in mind, the facts that rock slope and direction control colonization, and that climate change results in regional extinctions, can be explained. Vertical cliffs, which lack snow cover and are perpetually dry, are devoid of organisms. Boulder tops and edges can trap snow, but gravity and wind prevent excessive buildup. There, the organisms flourish. In places where snow-thinning cannot occur and snow drifts collect, rocks may contain living or dead communities. In light of these observations, the possibility of finding extraterrestrial endolithic communities on Mars cannot be eliminated.

Facile preparation of optically transparent and hydrophobic cellulose nanofibril composite films

Treesearch

Yan Qing; Zhiyong Cai; Yiqiang Wu; Chunhua Yao; Qinglin Wu; Xianjun Li

2015-01-01

Cellulose nanofibril (CNF) and epoxy nanocomposites with high visible light transmittance and low watersensitivity were manufactured by laminating thin layers of epoxy resin onto CNF films prepared through,pressurized filtration in combination with oven drying. Scanning Electron Microscopy (SEM) studiessuggest that the resin component bonded to the CNF substrate well....

A process for preparing an ultra-thin, adhesiveless, multi-layered, patterned polymer substrate

NASA Technical Reports Server (NTRS)

Bryant, Robert G. (Inventor); Kruse, Nancy H. M. (Inventor); Fox, Robert L. (Inventor); Tran, Sang Q. (Inventor)

1995-01-01

A process for preparing an ultra-thin, adhesiveless, multi-layered, patterned polymer substrate is disclosed. The process may be used to prepare both rigid and flexible cables and circuit boards. A substrate is provided and a polymeric solution comprising a self-bonding, soluble polymer and a solvent is applied to the substrate. Next, the polymer solution is dried to form a polymer coated substrate. The polymer coated substrate is metallized and patterned. At least one additional coating of the polymeric solution is applied to the metallized, patterned, polymer coated substrate and the steps of metallizing and patterning are repeated. Lastly, a cover coat is applied. When preparing a flexible cable and flexible circuit board, the polymer coating is removed from the substrate.

Deliquescence and efflorescence of small particles.

PubMed

McGraw, Robert; Lewis, Ernie R

2009-11-21

We examine size-dependent deliquescence/efflorescence phase transformation for particles down to several nanometers in size. Thermodynamic properties of inorganic salt particles, coated with aqueous solution layers of varying thickness and surrounded by vapor, are analyzed. A thin layer criterion (TLC) is introduced to define a limiting deliquescence relative humidity (RH(D)) for small particles. This requires: (1) equality of chemical potentials between salt in an undissolved core, and thin adsorbed solution layer, and (2) equality of chemical potentials between water in the thin layer and vapor phase. The usual bulk deliquescence conditions are recovered in the limit of large dry particle size. Nanosize particles are found to deliquesce at relative humidity just below the RH(D) on crossing a nucleation barrier, located at a critical solution layer thickness. This barrier vanishes precisely at the RH(D) defined by the TLC. Concepts and methods from nucleation theory including the kinetic potential, self-consistent nucleation theory, nucleation theorems, and the Gibbs dividing surface provide theoretical foundation and point to unifying features of small particle deliquescence/efflorescence processes. These include common thermodynamic area constructions, useful for interpretation of small particle water uptake measurements, and a common free-energy surface, with constant RH cross sections describing deliquescence and efflorescence related through the nucleation theorem.

Electron beam-induced radiation damage: the bubbling response in amorphous dried sodium phosphate buffer.

PubMed

Massover, William H

2010-06-01

Irradiation of an amorphous layer of dried sodium phosphate buffer (pH = 7.0) by transmission electron microscopy (100-120 kV) causes rapid formation of numerous small spherical bubbles [10-100 A (= 1-10 nm)] containing an unknown gas. Bubbling is detected even with the first low-dose exposure. In a thin layer (ca. 100-150 A), bubbling typically goes through nucleation, growth, possible fusion, and end-state, after which further changes are not apparent; co-irradiated adjacent areas having a slightly smaller thickness never develop bubbles. In moderately thicker regions (ca. over 200 A), there is no end-state. Instead, a complex sequence of microstructural changes is elicited during continued intermittent high-dose irradiation: nucleation, growth, early simple fusions, a second round of extensive multiple fusions, general reduction of matrix thickness (producing flattening and expansion of larger bubbles, occasional bubble fission, and formation of very large irregularly-shaped bubbles by a third round of compound fusion events), and slow shrinkage of all bubbles. The ongoing lighter appearance of bubble lumens, maintenance of their rounded shape, and extensive changes in size and form indicate that gas content continues throughout their surprisingly long lifetime; the thin dense boundary layer surrounding all bubbles is proposed to be the main mechanism for their long lifetime.

Drying bacterial biosaline patterns capable of vital reanimation upon rehydration: novel hibernating biomineralogical life formations.

PubMed

Gómez Gómez, José María; Medina, Jesús; Hochberg, David; Mateo-Martí, Eva; Martínez-Frías, Jesús; Rull, Fernando

2014-07-01

Water is the fundamental molecule for life on Earth. Thus, the search for hibernating life-forms in waterless environments is an important research topic for astrobiology. To date, however, the organizational patterns containing microbial life in extremely dry places, such as the deserts of Earth, the Dry Valleys of Antarctica, or Mars analog regolith, have been poorly characterized. Here, we report on the formation of bacterial biosaline self-organized drying patterns formed over plastic surfaces. These emerge during the evaporation of sessile droplets of aqueous NaCl salt 0.15 M solutions containing Escherichia coli cells. In the present study, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) analyses indicated that the bacterial cells and the NaCl in these biosaline formations are organized in a two-layered characteristic 3-D architectural morphology. A thin filmlike top layer formed by NaCl conjugated to, and intermingled with, "mineralized" bacterial cells covers a bottom layer constructed by the bulk of the nonmineralized bacterial cells; both layers have the same morphological pattern. In addition, optical microscopic time-lapsed movies show that the formation of these patterns is a kinetically fast process that requires the coupled interaction between the salt and the bacterial cells. Apparently, this mutual interaction drives the generative process of self-assembly that underlies the drying pattern formation. Most notably, the bacterial cells inside these drying self-assembled patterns enter into a quiescent suspended anhydrobiotic state resistant to complete desiccation and capable of vital reanimation upon rehydration. We propose that these E. coli biosaline drying patterns represent an excellent experimental model for understanding different aspects of anhydrobiosis phenomena in bacteria as well as for revealing the mechanisms of bacterially induced biomineralization, both highly relevant topics for the search of life in extraterrestrial locations.

Generation of gas-phase ions from charged clusters: an important ionization step causing suppression of matrix and analyte ions in matrix-assisted laser desorption/ionization mass spectrometry.

PubMed

Lou, Xianwen; van Dongen, Joost L J; Milroy, Lech-Gustav; Meijer, E W

2016-12-30

Ionization in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a very complicated process. It has been reported that quaternary ammonium salts show extremely strong matrix and analyte suppression effects which cannot satisfactorily be explained by charge transfer reactions. Further investigation of the reasons causing these effects can be useful to improve our understanding of the MALDI process. The dried-droplet and modified thin-layer methods were used as sample preparation methods. In the dried-droplet method, analytes were co-crystallized with matrix, whereas in the modified thin-layer method analytes were deposited on the surface of matrix crystals. Model compounds, tetrabutylammonium iodide ([N(Bu) 4 ]I), cesium iodide (CsI), trihexylamine (THA) and polyethylene glycol 600 (PEG 600), were selected as the test analytes given their ability to generate exclusively pre-formed ions, protonated ions and metal ion adducts respectively in MALDI. The strong matrix suppression effect (MSE) observed using the dried-droplet method might disappear using the modified thin-layer method, which suggests that the incorporation of analytes in matrix crystals contributes to the MSE. By depositing analytes on the matrix surface instead of incorporating in the matrix crystals, the competition for evaporation/ionization from charged matrix/analyte clusters could be weakened resulting in reduced MSE. Further supporting evidence for this inference was found by studying the analyte suppression effect using the same two sample deposition methods. By comparing differences between the mass spectra obtained via the two sample preparation methods, we present evidence suggesting that the generation of gas-phase ions from charged matrix/analyte clusters may induce significant suppression of matrix and analyte ions. The results suggest that the generation of gas-phase ions from charged matrix/analyte clusters is an important ionization step in MALDI-MS. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Electrical responses of artificial DNA nanostructures on solution-processed In-Ga-Zn-O thin-film transistors with multistacked active layers.

PubMed

Jung, Joohye; Kim, Si Joon; Yoon, Doo Hyun; Kim, Byeonghoon; Park, Sung Ha; Kim, Hyun Jae

2013-01-01

We propose solution-processed In-Ga-Zn-O (IGZO) thin-film transistors (TFTs) with multistacked active layers for detecting artificial deoxyribonucleic acid (DNA). Enhanced sensing ability and stable electrical performance of TFTs were achieved through use of multistacked active layers. Our IGZO TFT had a turn-on voltage (V(on)) of -0.8 V and a subthreshold swing (SS) value of 0.48 V/decade. A dry-wet method was adopted to immobilize double-crossover DNA on the IGZO surface, after which an anomalous hump effect accompanying a significant decrease in V(on) (-13.6 V) and degradation of SS (1.29 V/decade) was observed. This sensing behavior was attributed to the middle interfaces of the multistacked active layers and the negatively charged phosphate groups on the DNA backbone, which generated a parasitic path in the TFT device. These results compared favorably with those reported for conventional field-effect transistor-based DNA sensors with remarkable sensitivity and stability.

Colloidal transport phenomena of milk components during convective droplet drying.

PubMed

Fu, Nan; Woo, Meng Wai; Chen, Xiao Dong

2011-10-15

Material segregation has been reported for industrial spray-dried milk powders, which indicates potential material migration during drying process. The relevant colloidal transport phenomenon and the underlying mechanism are still under debate. This study extended the glass-filament single droplet drying technique to observe not only the drying behaviour but also the dissolution behaviour of the correspondingly dried single particle. At progressively longer drying stage, a solvent droplet (water or ethanol) was attached to the semi-dried milk particle and the interaction between the solvent and the particle was video-recorded. Based on the different dissolution and wetting behaviours observed, material migration during milk drying was studied. Fresh skim milk and fresh whole milk were investigated using water and ethanol as solvents. Fat started to accumulate on the surface as soon as drying was started. At the initial stage of drying, the fat layer remained thin and the solubility of the semi-dried milk particle was much affected by lactose and protein present underneath the fat layer. Fat kept accumulating at the surface as drying progressed and the accumulation was completed by the middle stage of drying. The results from drying of model milk materials (pure sodium caseinate solution and lactose/sodium caseinate mixed solution) supported the colloidal transport phenomena observed for the milk drying. When mixed with lactose, sodium caseinate did not form an apparent solvent-resistant protein shell during drying. The extended technique of glass-filament single droplet approach provides a powerful tool in examining the solubility of individual particle after drying. Copyright © 2011 Elsevier B.V. All rights reserved.

TiO2 brookite nanostructured thin layer on magneto-optical surface plasmon resonance transductor for gas sensing applications

NASA Astrophysics Data System (ADS)

Manera, M. G.; Colombelli, A.; Rella, R.; Caricato, A.; Cozzoli, P. D.; Martino, M.; Vasanelli, L.

2012-09-01

The sensing performance comparisons presented in this work were carried out by exploiting a suitable magneto-plasmonic sensor in both the traditional surface plasmon resonance configuration and the innovative magneto-optic surface plasmon resonance one. The particular multilayer transducer was functionalized with TiO2 Brookite nanorods layers deposited by matrix assisted pulsed laser evaporation, and its sensing capabilities were monitored in a controlled atmosphere towards different concentrations of volatile organic compounds mixed in dry air.

Resistivity profiling for mapping gravel layers that may control contaminant migration at the Amargosa Desert Research Site, Nevada

USGS Publications Warehouse

Lucius, Jeffrey E.; Abraham, Jared D.; Burton, Bethany L.

2008-01-01

Gaseous contaminants, including CFC 113, chloroform, and tritiated compounds, move preferentially in unsaturated subsurface gravel layers away from disposal trenches at a closed low-level radioactive waste-disposal facility in the Amargosa Desert about 17 kilometers south of Beatty, Nevada. Two distinct gravel layers are involved in contaminant transport: a thin, shallow layer between about 0.5 and 2.2 meters below the surface and a layer of variable thickness between about 15 and 30 meters below land surface. From 2003 to 2005, the U.S. Geological Survey used multielectrode DC and AC resistivity surveys to map these gravel layers. Previous core sampling indicates the fine-grained sediments generally have higher water content than the gravel layers or the sediments near the surface. The relatively higher electrical resistivity of the dry gravel layers, compared to that of the surrounding finer sediments, makes the gravel readily mappable using electrical resistivity profiling. The upper gravel layer is not easily distinguished from the very dry, fine-grained deposits at the surface. Two-dimensional resistivity models, however, clearly identify the resistive lower gravel layer, which is continuous near the facility except to the southeast. Multielectrode resistivity surveys provide a practical noninvasive method to image hydrogeologic features in the arid environment of the Amargosa Desert.

Modification of Indirect Solar Dryer for Simplicia Production

NASA Astrophysics Data System (ADS)

Purnomo, C. W.; Indarti, S.

2018-03-01

Simplicia is natural ingredient for herbal medicine that has been subjected to drying only. This study aims to develop an appropriate drying equipment to produce dried leaves of sambung nyawa (Gynura procumbens (Lour.) Merr.) or also called “longevity spinach”. Typical indirect solar drier was modified to be able to process more fresh leaves in order to speed up the production. The modification was done using double solar collector and wind powered ventilation. The double solar collector was applied in order to collect more solar energy for larger dimension of drying chamber, while the wind-ventilator was installed to provide forced convection of hot air flow inside the dryer. The drying kinetic including the drying constants were investigated using three common thin layer drying equations to model the drying behavior of the leaves. The moisture ratio (MR) depletion with respect to the drying time (t) of the leaves can be well represented by equation of MR=1.1732exp(-0.0993.t)-0.1732exp(-17.3871.t).

Endolithic Microbial Life in Extreme Cold Climate: Snow Is Required, but Perhaps Less Is More

PubMed Central

Sun, Henry J.

2013-01-01

Cyanobacteria and lichens living under sandstone surfaces in the McMurdo Dry Valleys require snow for moisture. Snow accumulated beyond a thin layer, however, is counterproductive, interfering with rock insolation, snow melting, and photosynthetic access to light. With this in mind, the facts that rock slope and direction control colonization, and that climate change results in regional extinctions, can be explained. Vertical cliffs, which lack snow cover and are perpetually dry, are devoid of organisms. Boulder tops and edges can trap snow, but gravity and wind prevent excessive buildup. There, the organisms flourish. In places where snow-thinning cannot occur and snow drifts collect, rocks may contain living or dead communities. In light of these observations, the possibility of finding extraterrestrial endolithic communities on Mars cannot be eliminated. PMID:24832803

Recent Advances in Doping of Molybdenum Disulfide: Industrial Applications and Future Prospects.

PubMed

Pham, Viet Phuong; Yeom, Geun Young

2016-11-01

Owing to their excellent physical properties, atomically thin layers of molybdenum disulfide (MoS 2 ) have recently attracted much attention due to their nonzero-gap property, exceptionally high electrical conductivity, good thermal stability, and excellent mechanical strength, etc. MoS 2 -based devices exhibit great potential for applications in optoelectronics and energy harvesting. Here, a comprehensive review of various doping strategies is presented, including wet doping and dry doping of atomically crystalline MoS 2 thin layers, and the progress made so far for their doping-based prospective applications is also discussed. Finally, several significant research issues for the prospects of doped-MoS 2 in industry, as a guide for 2D material community, are also provided. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tree thinning as an option to increase herbaceous yield of an encroached semi-arid savanna in South Africa

PubMed Central

Smit, Gert N

2005-01-01

Background The investigation was conducted in a savanna area covered by what was considered an undesirably dense stand of Colophospermum mopane trees, mainly because such a dense stand of trees often results in the suppression of herbaceous plants. The objectives of this study were to determine the influence of intensity of tree thinning on the dry matter yield of herbaceous plants (notably grasses) and to investigate differences in herbaceous species composition between defined subhabitats (under tree canopies, between tree canopies and where trees have been removed). Seven plots (65 × 180 m) were subjected to different intensities of tree thinning, ranging from a totally cleared plot (0 %) to plots thinned to the equivalent of 10 %, 20%, 35 %, 50% and 75 % of the leaf biomass of a control plot (100 %) with a tree density of 2711 plants ha-1. The establishment of herbaceous plants (grasses and forbs) in response to reduced competition from the woody plants was measured during three full growing seasons following the thinning treatments. Results The grass component reacted positively to the tree thinning in terms of total dry matter (DM) yield, but forbs were negatively influenced. Rainfall interacted with tree density and the differences between grass DM yields in thinned plots during years of below average rainfall were substantially higher than those of the control. At high tree densities, yields differed little between seasons of varying rainfall. The relation between grass DM yield and tree biomass was curvilinear, best described by the exponential regression equation. Subhabitat differentiation by C. mopane trees did provide some qualitative benefits, with certain desirable grass species showing a preference for the subhabitat under tree canopies. Conclusion While it can be concluded from this study that high tree densities suppress herbaceous production, the decision to clear/thin the C. mopane trees should include additional considerations. Thinning of C. mopane with the exclusive objective of increasing productivity of the grass layer would thus invariably involve a compromise situation where some trees should be left for the sake of the qualitative benefits on the herbaceous layer, soil enrichment, provision of browse and stability of the ecosystem. PMID:15921528

Long-wavelength Instability in Surface-tension-driven Bénard Convection

NASA Astrophysics Data System (ADS)

van Hook, Stephen J.

1997-03-01

Laboratory experiments and numerical simulations reveal that a liquid layer heated from below and possessing a free upper surface can undergo a long-wavelength deformational instability that causes rupture of the interface.(S. J. VanHook, M. F. Schatz, W. D. McCormick, J. B. Swift, and H. L. Swinney, Phys. Rev. Lett.) 75, 4397 (1995). Depending on the depth and thermal conductivity of the liquid and the overlying gas layer, the interface can rupture downwards and form a dry spot or rupture upwards and form a high spot. This long-wavelength instability competes with the formation of Bénard hexagons for thin or viscous liquid layers, or for liquid layers in microgravity.

Duplex Tear Film Evaporation Analysis.

PubMed

Stapf, M R; Braun, R J; King-Smith, P E

2017-12-01

Tear film thinning, hyperosmolarity, and breakup can cause irritation and damage to the human eye, and these form an area of active investigation for dry eye syndrome research. Recent research demonstrates that deficiencies in the lipid layer may cause locally increased evaporation, inducing conditions for breakup. In this paper, we explore the conditions for tear film breakup by considering a model for tear film dynamics with two mobile fluid layers, the aqueous and lipid layers. In addition, we include the effects of osmosis, evaporation as modified by the lipid, and the polar portion of the lipid layer. We solve the system numerically for reasonable parameter values and initial conditions and analyze how shifts in these cause changes to the system's dynamics.

Stretchable metal oxide thin film transistors on engineered substrate for electronic skin applications.

PubMed

Romeo, Alessia; Lacour, Stphanie P

2015-08-01

Electronic skins aim at providing distributed sensing and computation in a large-area and elastic membrane. Control and addressing of high-density soft sensors will be achieved when thin film transistor matrices are also integrated in the soft carrier substrate. Here, we report on the design, manufacturing and characterization of metal oxide thin film transistors on these stretchable substrates. The TFTs are integrated onto an engineered silicone substrate with embedded strain relief to protect the devices from catastrophic cracking. The TFT stack is composed of an amorphous In-Ga-Zn-O active layer, a hybrid AlxOy/Parylene dielectric film, gold electrodes and interconnects. All layers are prepared and patterned with planar, low temperature and dry processing. We demonstrate the interconnected IGZO TFTs sustain applied tensile strain up to 20% without electrical degradation and mechanical fracture. Active devices are critical for distributed sensing. The compatibility of IGZO TFTs with soft and biocompatible substrates is an encouraging step towards wearable electronic skins.

Quantification of Quercetin Obtained from Allium cepa Lam. Leaves and its Effects on Streptozotocin-induced Diabetic Neuropathy.

PubMed

Dureshahwar, Khan; Mubashir, Mohammed; Une, Hemant Devidas

2017-01-01

Antioxidant potential has protective effects in diabetic neuropathy (DN); hence, the present study was designed with an objective to quantify quercetin from shade-dried leaves of Allium cepa Lam. and to study its effects on streptozotocin (STZ)-induced chronic DN. The shade-dried leaves of A. cepa Lam. were extracted with methanol and then fractionated using ethyl acetate (ACEA). The quantification of quercetin in ACEA was evaluated by high-performance thin layer chromatography (HPTLC). The STZ (40 mg/kg) was administered to Sprague-Dawley rats (180-250 g) maintained at normal housing conditions. The STZ was administered once a day for 3 consecutive days. The elevation in blood glucose was monitored for 3 weeks periodically using flavin adenine dinucleotide-glucose dehydrogenase method by Contour TS glucometer. Rats showing blood glucose above 250 mg/dl were selected for the study. Animals were divided into eight groups. ACEA (25, 50, and 100 mg/kg), quercetin (40 mg/kg), metformin (120 mg/kg), and gabapentin (100 mg/kg) were given orally once a day for 2 weeks. The blood glucose level was again measured at the end of treatment to assess DN. Thermal hyperalgesia, cold allodynia, motor incoordination, and neurotoxicity were studied initially and at the end of 2-week treatment. Biochemical parameters were also evaluated after 2-week drug treatment. The quercetin present in ACEA was 4.82% by HPTLC. All the ACEA treatment reduces blood glucose level at the end of the 2-week study and shows a significant neuroprotective effect in STZ-induced DN in the above experimental models. The quercetin present in ACEA proved protective effect in STZ-induced DN. High-performance thin layer chromatography reveals the presence of 4.82% quercetin in Allium cepa ethyl acetate. (ACEA). Its investigation against various diabetic neuropathy biomarkers has proved that ACEA has significant blood glucose reducing action shown neuroprotective action in thermal hyperalgesia, motor incoordination, and biochemical parameters. Abbreviations Used : HPTLC: High-performance thin layer chromatography, TLC: Thin layer chromatography, UV: Ultraviolet, ACEA: Allium cepa ethyl acetate, STZ: Streptozotocin, LDL: Low-density lipids, HDL: High-density lipids.

Turbulent transport across an interface between dry and humid air in a stratified environment

NASA Astrophysics Data System (ADS)

Gallana, Luca; de Santi, Francesca; di Savino, Silvio; Iovieno, Michele; Ricchiardone, Renzo; Tordella, Daniela

2014-11-01

The transport of energy and water vapor across a thin layer which separates two decaying isotropic turbulent flows with different kinetic energy and humidity is considered. The interface is placed in a shearless stratified environment in temporal decay. This system reproduces a few aspects of small scale turbulent transport across a dry air/moist air interface in an atmospheric like context. In our incompressible DNS at Reλ = 250 , Boussinesq's approximation is used for momentum and energy transport while the vapor is modeled as a passive scalar (Kumar, Schumacher & Shaw 2014). We investigated different stratification levels with an initial Fr between 0.8 and 8 in presence of a kinetic energy ratio equal to 7. As the buoyancy term becomes of the same order of the inertial ones, a spatial redistribution of kinetic energy, dissipation and vapor concentration is observed. This eventually leads to the onset of a well of kinetic energy in the low energy side of the mixing layer which blocks the entrainment of dry air. Results are discussed and compared with laboratory and numerical experiments. A posteriori estimates of the eventual compression/expansion of fluid particles inside the interfacial mixing layer are given (Nance & Durran 1994).

Producing air-stable monolayers of phosphorene and their defect engineering

PubMed Central

Pei, Jiajie; Gai, Xin; Yang, Jiong; Wang, Xibin; Yu, Zongfu; Choi, Duk-Yong; Luther-Davies, Barry; Lu, Yuerui

2016-01-01

It has been a long-standing challenge to produce air-stable few- or monolayer samples of phosphorene because thin phosphorene films degrade rapidly in ambient conditions. Here we demonstrate a new highly controllable method for fabricating high quality, air-stable phosphorene films with a designated number of layers ranging from a few down to monolayer. Our approach involves the use of oxygen plasma dry etching to thin down thick-exfoliated phosphorene flakes, layer by layer with atomic precision. Moreover, in a stabilized phosphorene monolayer, we were able to precisely engineer defects for the first time, which led to efficient emission of photons at new frequencies in the near infrared at room temperature. In addition, we demonstrate the use of an electrostatic gate to tune the photon emission from the defects in a monolayer phosphorene. This could lead to new electronic and optoelectronic devices, such as electrically tunable, broadband near infrared lighting devices operating at room temperature. PMID:26794866

Biopolymer Green Lubricant for Sustainable Manufacturing

PubMed Central

Shi, Shih-Chen; Lu, Fu-I

2016-01-01

We report on the preparation of a biopolymer thin film by hydroxypropyl methylcellulose (HPMC), which can be used as a dry green lubricant in sustainable manufacturing. The thin films were characterized through scanning electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy; the films showed desirable levels of thickness, controllability, and uniformity. Tribology tests also showed desirable tribological and antiwear behaviors, caused by the formation of transfer layers. Zebrafish embryo toxicity studies showed that HPMC has excellent solubility and biocompatibility, which may show outstanding potential for applications as a green lubricant. The results of the present study show that these techniques for biopolymer HPMC provide an ecologically responsible and convenient method for preparing functional thin films, which is particularly applicable to sustainable manufacturing. PMID:28773462

Durable superhydrophobic paper enabled by surface sizing of starch-based composite films

NASA Astrophysics Data System (ADS)

Chen, Gang; Zhu, Penghui; Kuang, Yudi; Liu, Yu; Lin, Donghan; Peng, Congxing; Wen, Zhicheng; Fang, Zhiqiang

2017-07-01

Superhydrophobic paper with remarkable durability is of considerable interest for its practical applications. In this study, a scalable, inexpensive, and universal surface sizing technique was implemented to prepare superhydrophobic paper with enhanced durability. A thin layer of starch-based composite, acting as a bio-binder, was first coated onto the paper surface by a sophisticated manufacturing technique called surface sizing, immediately followed by a spray coating of hexamethyl disilazane treated silica nanoparticles (HMDS-SiNPs) dispersed in ethanol on the surface of the wet starch-coated sheet, and the dual layers dried at the same time. Consequently, durable superhydrophobic paper with bi-layer structure was obtained after air drying. The as-prepared superhydrophobic paper not only exhibited a self-cleaning behavior, but also presented an enhanced durability against scratching, bending/deformation, as well as moisture. The universal surface sizing of starch-based composites may pave the way for the up-scaled and cost-effective production of durable superhydrophobic paper.

The thin-layer drying characteristics of sewage sludge by the appropriate foaming pretreatment.

PubMed

Wang, Hui-Ling; Yang, Zhao-Hui; Huang, Jing; Wang, Li-Ke; Gou, Cheng-Liu; Yan, Jing-Wu; Yang, Jian

2014-01-01

As dewatered sludge is highly viscous and sticky, the combination of foaming pretreatment and drying process seems to be an alternative method to improve the drying performance of dewatered sludge. In this study, CaO addition followed by mechanical whipping was employed for foaming the dewatered sludge. It was found that the foams were stable and the diameters of bubbles mainly ranged from 0.1 to 0.3 mm. The drying experiments were carried out in a drying oven in the convective mode. The results indicated that foamed sludge at 0.70 g/cm(3) had the best drying performance at each level of temperature, which could save 35-45% drying time to reach 20% moisture content compared with the non-foamed sludge. The drying rate of foamed sludge at 0.70 g/cm(3) was improved with the increasing of drying temperature. The impact of sample thickness on drying rate was not obvious when the sample thickness increased from 2 to 8 mm. Different mathematical models were used for the simulation of foamed sludge drying curves. The Wang and Singh model represented the drying characteristics better than other models with coefficient of determination values over 0.99.

Vis-NIR hyperspectral imaging in visualizing moisture distribution of mango slices during microwave-vacuum drying.

PubMed

Pu, Yuan-Yuan; Sun, Da-Wen

2015-12-01

Mango slices were dried by microwave-vacuum drying using a domestic microwave oven equipped with a vacuum desiccator inside. Two lab-scale hyperspectral imaging (HSI) systems were employed for moisture prediction. The Page and the Two-term thin-layer drying models were suitable to describe the current drying process with a fitting goodness of R(2)=0.978. Partial least square (PLS) was applied to correlate the mean spectrum of each slice and reference moisture content. With three waveband selection strategies, optimal wavebands corresponding to moisture prediction were identified. The best model RC-PLS-2 (Rp(2)=0.972 and RMSEP=4.611%) was implemented into the moisture visualization procedure. Moisture distribution map clearly showed that the moisture content in the central part of the mango slices was lower than that of other parts. The present study demonstrated that hyperspectral imaging was a useful tool for non-destructively and rapidly measuring and visualizing the moisture content during drying process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of pre-drying treatments on solution-coated organic thin films for active-matrix organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Shin, Dongkyun; Hong, Ki-Young; Park, Jongwoon

2017-12-01

Due to capillary rise, organic thin films fabricated by solution coating exhibit the concave thickness profile. It is found that the thickness and emission uniformities within pixels vary depending sensitively on the pre-drying treatment that has been done before hard bake. We investigate its effect on the film quality by varying the temperature, time, pressure, fluid flow-related solute concentration, and evaporation-related solvent. To this end, we carry out spin coatings of a non-aqueous poly(N-vinylcarbazole) (PVK) for a hole transporting blanket layer. With a low-boiling-point (BP) organic solvent, the pre-drying makes no significant impact on the thickness profiles. With a high-BP organic solvent, the PVK films pre-dried in a vacuum for a sufficient time exhibit very uniform light emission in the central region, but non-emission phenomenon near the perimeter of pixels. It is addressed that such a non-emission phenomenon can be suppressed to some extent by decreasing the vacuum pressure. However, the rapid evaporation by heat conduction during the pre-drying degrades the thickness uniformity due to a rapid microflow of solute from the edge to the center. No further enhancement in the thickness uniformity is obtained by varying the solute concentration and using a mixture of low- and high-BP solvents.

Mass production of the large-sized nuclear plate for J-PARC E07

NASA Astrophysics Data System (ADS)

Ito, Hiroki; Nakazama, Kazuma; Hoshino, Kaoru; Yoshida, Jyunya; Tint, Khin Than; Soe, Mint Kyaw; Kinbara, Shinji; Mishina, Akihiro; Endo, Yoko; Kobayashi, Hidetaka; J-PARC E07 Collaboration

2014-09-01

In J-PARC E07, about 102 double lambda hypernuclei will be detected, which is 10 times or more than that of the KEK PS-E373 experiment. Therefore, it is necessary for large-scale emulsion plates to avoid time-consuming job for exchange emulsion stack in beam exposure. We also use huge amount of emulsion gel with weight of 2.1 t, which is about 3 times' quantity used for E373. Nuclear emulsion plate is made of photographic emulsion gel as a dry film. Melted gel in 40°C is poured on a thin polystyrene film in the size of 710 × 700 mm2. These sheets were dried slowly for two days in drying cabinet under 28°C and RH. 75%. After drying, the surface was coated by thin gelatin layer with 0.3 μm thickness. Regarding the 2nd face, it was poured and coated in the same manner. Finally we dry it well under 25°C and RH. 60% and cut into four 350 × 345 mm2 plates. We evaluated the performance about these plates. The length of upper, lower, right-hand and left-hand side are 345.08 +/- 0.05 mm, 345.23 +/- 0.13 mm, 350.03 +/- 0.04 mm, and 350.80 +/- 0.05 mm, respectively. The density is 3.676 +/- 0.032 g/cm3, enough quality for the experiment.

Low-temperature atomic layer deposition of TiO{sub 2} thin layers for the processing of memristive devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porro, Samuele, E-mail: samuele.porro@polito.it; Conti, Daniele; Guastella, Salvatore

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 asmore » 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.« less

Drying kinetics and characteristics of combined infrared-vacuum drying of button mushroom slices

NASA Astrophysics Data System (ADS)

Salehi, Fakhreddin; Kashaninejad, Mahdi; Jafarianlari, Ali

2017-05-01

Infrared-vacuum drying characteristics of button mushroom ( Agaricus bisporus) were evaluated in a combined dryer system. The effects of drying parameters, including infrared radiation power (150-375 W), system pressure (5-15 kPa) and time (0-160 min) on the drying kinetics and characteristics of button mushroom slices were investigated. Both the infrared lamp power and vacuum pressure influenced the drying time of button mushroom slices. The rate constants of the nine different kinetic's models for thin layer drying were established by nonlinear regression analysis of the experimental data which were found to be affected mainly by the infrared power level while system pressure had a little effect on the moisture ratios. The regression results showed that the Page model satisfactorily described the drying behavior of button mushroom slices with highest R value and lowest SE values. The effective moisture diffusivity increases as power increases and range between 0.83 and 2.33 × 10-9 m2/s. The rise in infrared power has a negative effect on the ΔE and with increasing in infrared radiation power it was increased.

Dry-spray deposition of TiO2 for a flexible dye-sensitized solar cell (DSSC) using a nanoparticle deposition system (NPDS).

PubMed

Kim, Min-Saeng; Chun, Doo-Man; Choi, Jung-Oh; Lee, Jong-Cheon; Kim, Yang Hee; Kim, Kwang-Su; Lee, Caroline Sunyong; Ahn, Sung-Hoon

2012-04-01

TiO2 powders were deposited on indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates for application to the photoelectrode of a dye-sensitized solar cell (DSSC). In the conventional DSSC manufacturing process, a semiconductor oxide such as TiO2 powder requires a sintering process at higher temperature than the glass transition temperature (T(g)) of polymers, and thus utilization of flexible polymer substrates in DSSC research has been constrained. To overcome this restriction related to sintering, we used a nanoparticle deposition system (NPDS) that could produce a thin coating layer through a dry-spray method under atmospheric pressure at room temperature. The powder was sprayed through a slit-type nozzle having a 0.4 x 10 mm2 rectangular outlet. In order to determine the deposited TiO2 thickness, five kinds of TiO2 layered specimens were prepared, where the specimens have single and double layer structures. Deposited powders on the ITO coated PET substrates were observed using FE-SEM and a scan profiler The thicker TiO2 photoelectrode with a DSSC having a double layer structure showed higher energy efficiency than the single layer case. The highest fabricated flexible DSSC displayed a short circuit current density J(sc) = 1.99 mA cm(-2), open circuit voltage V(oc) = 0.71 V, and energy efficiency eta = 0.94%. These results demonstrate the possibility of utilizing the dry-spray method to fabricate a TiO2 layer on flexible polymer substrates at room temperature under atmospheric pressure.

Effect of ultrasound pre-treatment on the drying kinetics of brown seaweed Ascophyllum nodosum.

PubMed

Kadam, Shekhar U; Tiwari, Brijesh K; O'Donnell, Colm P

2015-03-01

The effect of ultrasound pre-treatment on the drying kinetics of brown seaweed Ascophyllum nodosum under hot-air convective drying was investigated. Pretreatments were carried out at ultrasound intensity levels ranging from 7.00 to 75.78 Wcm(-2) for 10 min using an ultrasonic probe system. It was observed that ultrasound pre-treatments reduced the drying time required. The shortest drying times were obtained from samples pre-treated at 75.78 Wcm(-2). The fit quality of 6 thin-layer drying models was also evaluated using the determination of coefficient (R(2)), root means square error (RMSE), AIC (Akaike information criterion) and BIC (Bayesian information criterion). Drying kinetics were modelled using the Newton, Henderson and Pabis, Page, Wang and Singh, Midilli et al. and Weibull models. The Newton, Wang and Singh, and Midilli et al. models showed the best fit to the experimental drying data. Color of ultrasound pretreated dried seaweed samples were lighter compared to control samples. It was concluded that ultrasound pretreatment can be effectively used to reduce the energy cost and drying time for drying of A. nodosum. Copyright © 2014 Elsevier B.V. All rights reserved.

Imbibition with swelling: Capillary rise in thin deformable porous media

NASA Astrophysics Data System (ADS)

Kvick, Mathias; Martinez, D. Mark; Hewitt, Duncan R.; Balmforth, Neil J.

2017-07-01

The imbibition of a liquid into a thin deformable porous substrate driven by capillary suction is considered. The substrate is initially dry and has uniform porosity and thickness. Two-phase flow theory is used to describe how the liquid flows through the pore space behind the wetting front when out-of-plane deformation of the solid matrix is considered. Neglecting gravity and evaporation, standard shallow-layer scalings are used to construct a reduced model of the dynamics. The model predicts convergence to a self-similar behavior in all regions except near the wetting front, where a boundary layer arises whose structure narrows with the advance of the front. Over time, the rise height approaches the similarity scaling of t1 /2, as in the classical Washburn or BCLW law. The results are compared with a series of laboratory experiments using cellulose paper sheets, which provide qualitative agreement.

Fire severity is more sensitive to low fuel moisture content on Calluna heathlands than on peat bogs.

PubMed

Grau-Andrés, Roger; Davies, G Matt; Gray, Alan; Scott, E Marian; Waldron, Susan

2018-03-01

Moorland habitats dominated by the dwarf shrub Calluna vulgaris provide important ecosystem services. Drought is projected to intensify throughout their range, potentially leading to increased fire severity as moisture is a key control on severity. We studied the effect of low fuel moisture content (FMC) on fire severity by using 2×2m rain-out shelters prior to completing 19 experimental fires in two sites in Scotland (UK): a dry heath with thin organic soils and a raised bog with deep, saturated peat, both dominated by Calluna vulgaris. Reduced FMC of the moss and litter (M/L) layer at both sites, and the soil moisture of the dry heath, increased fire-induced consumption of the M/L layer and soil heating at both sites. Increase in fire severity was greater at the dry heath than at the raised bog, e.g. average maximum temperatures at the soil surface increased from 31°C to 189°C at the dry heath, but only from 10°C to 15°C at the raised bog. Substantial M/L layer consumption was observed when its FMC was below 150%. This led to larger seasonal and daily soil temperature fluctuation, particularly at the dry heath during warm months. The results suggest that low FMC following predicted changes in climate are likely to increase wildfire severity and that the impact on vegetation composition and carbon stores may be greater at heathlands than at peatlands. Managed burning aiming to minimise fire severity (e.g. ignition of the M/L layer and exposure to lethal temperatures of ericoid seeds) should be carried out when the FMC of the M/L layer is above 150% and the FMC of the soil is above 200-300%. Copyright © 2017 Elsevier B.V. All rights reserved.

Long-Wavelength Rupturing Instability in Surface-Tension-Driven Benard Convection

NASA Technical Reports Server (NTRS)

Swift, J. B.; Hook, Stephen J. Van; Becerril, Ricardo; McCormick, W. D.; Swinney, H. L.; Schatz, Michael F.

1999-01-01

A liquid layer with a free upper surface and heated from below is subject to thermocapillary-induced convective instabilities. We use very thin liquid layers (0.01 cm) to significantly reduce buoyancy effects and simulate Marangoni convection in microgravity. We observe thermocapillary-driven convection in two qualitatively different modes, short-wavelength Benard hexagonal convection cells and a long-wavelength interfacial rupturing mode. We focus on the long-wavelength mode and present experimental observations and theoretical analyses of the long-wavelength instability. Depending on the depths and thermal conductivities of the liquid and the gas above it, the interface can rupture downwards and form a dry spot or rupture upwards and form a high spot. Linear stability theory gives good agreement to the experimental measurements of onset as long as sidewall effects are taken into account. Nonlinear theory correctly predicts the subcritical nature of the bifurcation and the selection between the dry spot and high spots.

Method for making conductors for ferrite memory arrays. [from pre-formed metal conductors

NASA Technical Reports Server (NTRS)

Heckler, C. H.; Baba, P. D.; Bhiwandker, N. C. (Inventor)

1974-01-01

The ferrite memory arrays are made from pre-formed metal conductors for the ferrite arrays. The conductors are made by forming a thin sheet of a metallizing paste of metal alloy powder, drying the paste layer, bisque firing the dried sheet at a first temperature, and then punching the conductors from the fired sheet. During the bisque firing, the conductor sheet shrinks to 58 percent of its pre-fired volume and the alloy particles sinter together. The conductors are embedded in ferrite sheet material and finally fired at a second higher temperature during which firing the conductors shrink approximately the same degree as the ferrite material.

Study of cultivation and growth rate kinetic for mixed cultures of local microalgae as third generation (G-3) bioethanol feedstock in thin layer photobioreactor

NASA Astrophysics Data System (ADS)

Prihastuti Yuarrina, Wahyu; Surya Pradana, Yano; Budiman, Arief; Majid, Akmal Irfan; Indarto; Agus Suyono, Eko

2018-05-01

The increasing use of fossil fuels causes the depletion in supply and contributes to climate change by GHG emissions into the atmosphere. Microalgae indicate as renewable and sustainable energy sources as they have a high potential for producing large amounts of biomass for third-generation biofuels (bioethanol and biodiesel) feedstock. However, there are several parameters which should be considered for microalgae cultivation, such as environmental conditions, medium composition and microalgae species. The aim of this research was to study cultivation of mixed microalgae cultures (Glagah consortium and Arthrospira maxima) in a thin layer photobioreactor. Farmpion medium, Bold’s Basal Medium (BBM) and Thoriq Eko Arief (TEA) medium were investigated as cultivation medium for bioethanol feedstock for 7 days. The results showed that the highest dry weight concentration of microalgae was in Farmpion medium (0.35 mg/ml) and the highest carbohydrate concentration of microalgae was in BBM (0.14 mg/ml). Thus, the optimum medium of microalgae cultivation for bioethanol feedstock was BBM because of the highest carbohydrate-dry weight ratio (0.88). In addition, mathematical approach by using Contois model was used to find out the growth rate of microalgae cultivation in each medium.

Thin Layer Drying Kinetics of By-Products from Olive Oil Processing

PubMed Central

Montero, Irene; Miranda, Teresa; Arranz, Jose Ignacio; Rojas, Carmen Victoria

2011-01-01

The thin-layer behavior of by-products from olive oil production was determined in a solar dryer in passive and active operation modes for a temperature range of 20–50 °C. The increase in the air temperature reduced the drying time of olive pomace, sludge and olive mill wastewater. Moisture ratio was analyzed to obtain effective diffusivity values, varying in the oil mill by-products from 9.136 × 10−11 to 1.406 × 10−9 m2/s in forced convection (ma = 0.22 kg/s), and from 9.296 × 10−11 to 6.277 × 10−10 m2/s in natural convection (ma = 0.042 kg/s). Diffusivity values at each temperature were obtained using the Fick’s diffusion model and, regardless of the convection, they increased with the air temperature. The temperature dependence on the effective diffusivity was determined by an Arrhenius type relationship. The activation energies were found to be 38.64 kJ/mol, 30.44 kJ/mol and 47.64 kJ/mol for the olive pomace, the sludge and the olive mill wastewater in active mode, respectively, and 91.35 kJ/mol, 14.04 kJ/mol and 77.15 kJ/mol in natural mode, in that order. PMID:22174639

A simple analytical platform based on thin-layer chromatography coupled with paper-based analytical device for determination of total capsaicinoids in chilli samples.

PubMed

Dawan, Phanphruk; Satarpai, Thiphol; Tuchinda, Patoomratana; Shiowatana, Juwadee; Siripinyanond, Atitaya

2017-01-01

A new analytical platform based on the use of thin-layer chromatography (TLC) coupled with paper-based analytical device (PAD) was developed for the determination of total capsaicinoids in chilli samples. This newly developed TLC-PAD is simple and low-cost without any requirement of special instrument or skillful person. The analysis consisted of two steps, i.e., extraction of capsaicinoids from chilli samples by using ethanol as solvent and separation of capsaicinoids by thin-layer chromatography (TLC) and elution of capsaicinoids from the TLC plate with in situ colorimetric detection of capsaicinoids on the PAD. For colorimetric detection, Folin-Ciocalteu reagent was used to detect phenolic functional group of capsaicinoids yielding the blue color. The blue color on the PAD was imaged by a scanner followed by evaluation of its grayscale intensity value by ImageJ program. This newly developed TLC-PAD method provided a linear range from 50 to 1000mgL -1 capsaicinoids with the limit of detection as low as 50mgL -1 capsaicinoids. The proposed method was applied to determine capsaicinoids in dried chilli and seasoning powder samples and the results were in good agreement with those obtained by HPLC method. Copyright © 2016 Elsevier B.V. All rights reserved.

Convective drying of hawthorn fruit (Crataegus spp.): Effect of experimental parameters on drying kinetics, color, shrinkage, and rehydration capacity.

PubMed

Aral, Serdar; Beşe, Ayşe Vildan

2016-11-01

Thin layer drying characteristics and physicochemical properties of hawthorn fruit (Crataegus spp.) were investigated using a convective dryer at air temperatures 50, 60 and 70°C and air velocities of 0.5, 0.9 and 1.3m/s. The drying process of hawthorn took place in the falling rate period, and the drying time decreased with increasing air temperature and velocity. The experimental data obtained during the drying process were fitted to eleven different mathematical models. The Midilli et al.'s model was found to be the best appropriate model for explaining the drying behavior of hawthorn fruit. Effective moisture diffusion coefficients (Deff) were calculated by Fick's diffusion model and their values varied from 2.34×10(-10)m(2)/s to 2.09×10(-9)m(2)/s. An Arrhenius-type equation was applied to determine the activation energies. While the shrinkage decreased, the rehydration ratio increased with increasing air temperature and air velocity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Method for Making a Fuel Cell from a Solid Oxide Monolithic Framework

NASA Technical Reports Server (NTRS)

Sofie, Stephen W. (Inventor); Cable, Thomas L. (Inventor)

2014-01-01

The invention is a novel solid oxide fuel cell (SOFC) stack comprising individual bi-electrode supported fuel cells in which a thin electrolyte is supported between electrodes of essentially equal thickness. Individual cell units are made from graded pore ceramic tape that has been created by the freeze cast method followed by freeze drying. Each piece of graded pore tape later becomes a graded pore electrode scaffold that subsequent to sintering, is made into either an anode or a cathode by means of appropriate solution and thermal treatment means. Each cell unit is assembled by depositing of a thin coating of ion conducting ceramic material upon the side of each of two pieces of tape surface having the smallest pore openings, and then mating the coated surfaces to create an unsintered electrode scaffold pair sandwiching an electrolyte layer. The opposing major outer exposed surfaces of each cell unit is given a thin coating of electrically conductive ceramic, and multiple cell units are stacked, or built up by stacking of individual cell layers, to create an unsintered fuel cell stack. Ceramic or glass edge seals are installed to create flow channels for fuel and air. The cell stack with edge sealants is then sintered into a ceramic monolithic framework. Said solution and thermal treatments means convert the electrode scaffolds into anodes and cathodes. The thin layers of electrically conductive ceramic become the interconnects in the assembled stack.

Ultra-thin resin embedding method for scanning electron microscopy of individual cells on high and low aspect ratio 3D nanostructures.

PubMed

Belu, A; Schnitker, J; Bertazzo, S; Neumann, E; Mayer, D; Offenhäusser, A; Santoro, F

2016-07-01

The preparation of biological cells for either scanning or transmission electron microscopy requires a complex process of fixation, dehydration and drying. Critical point drying is commonly used for samples investigated with a scanning electron beam, whereas resin-infiltration is typically used for transmission electron microscopy. Critical point drying may cause cracks at the cellular surface and a sponge-like morphology of nondistinguishable intracellular compartments. Resin-infiltrated biological samples result in a solid block of resin, which can be further processed by mechanical sectioning, however that does not allow a top view examination of small cell-cell and cell-surface contacts. Here, we propose a method for removing resin excess on biological samples before effective polymerization. In this way the cells result to be embedded in an ultra-thin layer of epoxy resin. This novel method highlights in contrast to standard methods the imaging of individual cells not only on nanostructured planar surfaces but also on topologically challenging substrates with high aspect ratio three-dimensional features by scanning electron microscopy. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Nanoscale pillar arrays for separations

DOE PAGES

Kirchner, Teresa; Strickhouser, Rachel; Hatab, Nahla; ...

2015-04-01

The work presented herein evaluates silicon nano-pillar arrays for use in planar chromatography. Electron beam lithography and metal thermal dewetting protocols were used to create nano-thin layer chromatography platforms. With these fabrication methods we are able to reduce the size of the characteristic features in a separation medium below that used in ultra-thin layer chromatography; i.e. pillar heights are 1-2μm and pillar diameters are typically in the 200- 400nm range. In addition to the intrinsic nanoscale aspects of the systems, it is shown they can be further functionalized with nanoporous layers and traditional stationary phases for chromatography; hence exhibit broad-rangingmore » lab-on-a-chip and point-of-care potential. Because of an inherent high permeability and very small effective mass transfer distance between pillars, chromatographic efficiency can be very high but is enhanced herein by stacking during development and focusing while drying, yielding plate heights in the nm range separated band volumes. Practical separations of fluorescent dyes, fluorescently derivatized amines, and anti-tumor drugs are illustrated.« less

Highly reliable photosensitive organic-inorganic hybrid passivation layers for a-InGaZnO thin-film transistors

NASA Astrophysics Data System (ADS)

Bermundo, Juan Paolo; Ishikawa, Yasuaki; Yamazaki, Haruka; Nonaka, Toshiaki; Fujii, Mami N.; Uraoka, Yukiharu

2015-07-01

We report the fabrication of a photosensitive hybrid passivation material on amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) that greatly enhance its stability and improve its electrical characteristics. The hybrid passivation based on polysilsesquioxane is transparent and fabricated using a simple solution process. Because the passivation is photosensitive, dry etching was never performed during TFT fabrication. TFTs passivated with this material had a small threshold voltage shift of 0.5 V during positive bias stress, 0.5 V during negative bias stress, and -2.5 V during negative bias illumination stress. Furthermore, TFTs passivated by this layer were stable after being subjected to high relative humidity stress — confirming the superb barrier ability of the passivation. Analysis of secondary ion mass spectrometry showed that a large amount of hydrogen, carbon, and fluorine can be found in the channel region. We show that both hydrogen and fluorine reduced oxygen vacancies and that fluorine stabilized weak oxygen and hydroxide bonds. These results demonstrate the large potential of photosensitive hybrid passivation layers as effective passivation materials.

Artificial twin-layer configurations of Zn(O,S) films by radio frequency sputtering in all dry processed eco-friendly Cu(In,Ga)Se2 solar cells

NASA Astrophysics Data System (ADS)

Liu, Wei; Fan, Yu; Li, Xiaodong; Lin, Shuping; Liu, Yang; Shi, Sihan; Wang, He; Zhou, Zhiqiang; Zhang, Yi; Sun, Yun

2018-03-01

Cu(In,Ga)Se2 thin film solar cells are of great interest for research and industrial applications with their high conversion efficiencies, long-term stability and significant lifetimes. Such a solar cell of a p-n junction consists of p-type Cu(In,Ga)Se2 films as a light absorber and n-type CdS as a buffer layer, which often emerges with intrinsic ZnO. Aimed at eco-friendly fabrication protocols, a large number of strategies have been investigated to fabricate a Cd-free n-type buffer layer such as Zn(O,S) in Cu(In,Ga)Se2 solar cells. Also, if the Zn(O,S) films are prepared by coevaporation or sputtering, it will offer high compatibility with the preferred mass production. Here, we propose and optimize a dry method for Zn(O,S) deposition in a radio frequency sputtering. In particular, the strategy for the twin-layer configurations of Zn(O,S) films not only greatly improve their electrical conductance and suppress charge carrier recombination, but also avoid degradation of the Zn(O,S)/Cu(In,Ga)Se2 interfaces. Indeed, the high quality of such twin Zn(O,S) layers have been reflected in the similar conversion efficiencies of the complete solar cells as well as the large short-circuit current density, which exceeds the CdS reference device. In addition, Zn(O,S) twin layers have reduced the production time and materials by replacing the CdS/i-ZnO layers, which removes two fabrication steps in the multilayered thin film solar cells. Furthermore, the device physics for such improvements have been fully unveiled with both experimental current-voltage and capacitance-voltage spectroscopies and device simulations via wxAMPS program. Finally, the proposed twin-layer Zn(O,S)/Cu(In,Ga)Se2 interfaces account for the broadening of the depletion region of photogenerated charge carriers, which greatly suppress the carrier recombination at the space charge region, and eventually lead to the more efficient collection of charge carriers at both electrodes.

Explosive Testing of Class 1.3 Rocket Booster Propellant

DTIC Science & Technology

1994-08-01

molds were lined with 0.025 mm (0.001 in.) Velostat conductive plastic sheet and sprayed with a mold release that dried leaving fine Teflon powder... Velostat sheet (0.03 in.) was wrapped around the sample and grounded for improved electrostatic safety. Similar to previous cylinder tests, the...layer of thin Velostat plastic sheet, its contribution to camera viewing distortion of the flame front is not known. Overall, an average velocity over

Time dependence of carbon film deposition on SnO{sub 2}/Si using DC unbalanced magnetron sputtering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alfiadi, H., E-mail: yudi@fi.itb.ac.id; Aji, A. S., E-mail: yudi@fi.itb.ac.id; Darma, Y., E-mail: yudi@fi.itb.ac.id

Carbon deposition on SnO{sub 2} layer has been demonstrated at low temperature using DC unbalanced magnetron-sputtering technique for various time depositions. Before carbon sputtering process, SnO{sub 2} thin layer is grown on silicon substrate by thermal evaporation method using high purity Sn wire and then fully oxidizes by dry O{sub 2} at 225°C. Carbon sputtering process was carried out at pressure of 4.6×10{sup −2} Torr by keeping the substrate temperature of 300 °C for sputtering deposition time of 1 to 4 hours. The properties of SnO{sub 2}/Si structure and carbon thin film on SnO{sub 2} is characterized using SEM, EDAX,more » XRD, FTIR, and Raman Spectra. SEM images and XRD spectra show that SnO2 thin film has uniformly growth on Si substrate and affected by annealing temperature. Raman and FTIR results confirm the formation of carbon-rich thin film on SnO{sub 2}. In addition, XRD spectra indicate that some structural change occur by increasing sputtering deposition time. Furthermore, the change of atomic structure due to the thermal annealing is analized by XRD spectra and Raman spectroscopy.« less

Nanocrystalline SnO2:F thin films for liquid petroleum gas sensors.

PubMed

Chaisitsak, Sutichai

2011-01-01

This paper reports the improvement in the sensing performance of nanocrystalline SnO(2)-based liquid petroleum gas (LPG) sensors by doping with fluorine (F). Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. The effect of F concentration on the structural, surface morphological and LPG sensing properties of the SnO(2) films was investigated. Atomic Force Microscopy (AFM) and X-ray diffraction pattern measurements showed that the obtained thin films are nanocrystalline SnO(2) with nanoscale-textured surfaces. Gas sensing characteristics (sensor response and response/recovery time) of the SnO(2):F sensors based on a planar interdigital structure were investigated at different operating temperatures and at different LPG concentrations. The addition of fluorine to SnO(2) was found to be advantageous for efficient detection of LPG gases, e.g., F-doped sensors are more stable at a low operating temperature (300 °C) with higher sensor response and faster response/recovery time, compared to un-doped sensor materials. The sensors based on SnO(2):F films could detect LPG even at a low level of 25% LEL, showing the possibility of using this transparent material for LPG leak detection.

Evaporator fouling tendencies of thin stillage and concentrates from the dry grind process

USDA-ARS?s Scientific Manuscript database

In the US, more than 200 maize processing plants use multiple effect evaporators to remove water from thin stillage and steepwater during dry grind and wet milling processes, respectively. During the dry grind process, unfermentables are centrifuged and the liquid fraction, thin stillage, is concen...

Effect of elastic excitations on the surface structure of hadfield steel under friction

NASA Astrophysics Data System (ADS)

Kolubaev, A. V.; Ivanov, Yu. F.; Sizova, O. V.; Kolubaev, E. A.; Aleshina, E. A.; Gromov, V. E.

2008-02-01

The structure of the Hadfield steel (H13) surface layer forming under dry friction is examined. The deformation of the material under the friction surface is studied at a low slip velocity and a low pressure (much smaller than the yields stress of H13 steel). The phase composition and defect substructure on the friction surface are studied using scanning, optical, and diffraction electron microscopy methods. It is shown that a thin highly deformed nanocrystalline layer arises near the friction surface that transforms into a polycrystalline layer containing deformation twins and dislocations. The nanocrystalline structure and the presence of oxides in the surface layer and friction zone indicate a high temperature and high plastic strains responsible for the formation of the layer. It is suggested that the deformation of the material observed far from the surface is due to elastic wave generation at friction.

Radiation treatment of herb tea for the reduction of microbial contamination (Flores chamomillae)

NASA Astrophysics Data System (ADS)

Katušin-Ražem, B.; Ražem, D.; Dvornik, I.; Matić, S.

A survey of microbiological contamination of dried chamomile flowers indicates the presence of thermophilic bacteria up to the level of 10 4 per gram. This material often contains insecticides which have been used to reduce post-harvest losses. This work was undertaken in order to study the feasibility of radiation treatment of dried chamomile flowers as the only acceptable process for reduction of microbial contamination and as an alternative to chemical treatment. The main microbial contaminants were identified and typical contamination levels established. Survival curves of the irradiated microflora were obtained as a function of gamma radiation dose. Chemical composition of chamomile oil was followed by spectroscopy, thin layer and gas chromatography. No untoward effects of radiation treatment on active components were found, which indicates the usefulness of radiation treatment of dry flowers.

Composites with improved fiber-resin interfacial adhesion

NASA Technical Reports Server (NTRS)

Cizmecioglu, Muzaffer (Inventor)

1989-01-01

The adhesion of fiber reinforcement such as high modulus graphite to a matrix resin such as polycarbonate is greatly enhanced by applying a very thin layer, suitably from 50 Angstroms to below 1000 Angstroms, to the surface of the fiber such as by immersing the fiber in a dilute solution of the matrix resin in a volatile solvent followed by draining to remove excess solution and air drying to remove the solvent. The thin layer wets the fiber surface. The very dilute solution of matrix resin is able to impregnate multifilament fibers and the solution evenly flows onto the surface of the fibers. A thin uniform layer is formed on the surface of the fiber after removal of the solvent. The matrix resin coated fiber is completely wetted by the matrix resin during formation of the composite. Increased adhesion of the resin to the fibers is observed at fracture. At least 65 percent of the surface of the graphite fiber is covered with polycarbonate resin at fracture whereas uncoated fibers have very little matrix resin adhering to their surfaces at fracture and epoxy sized graphite fibers exhibit only slightly higher coverage with matrix resin at fracture. Flexural modulus of the composite containing matrix resin coated fibers is increased by 50 percent and flexural strength by 37 percent as compared to composites made with unsized fibers.

Research on the drying kinetics of household food waste for the development and optimization of domestic waste drying technique.

PubMed

Sotiropoulos, A; Malamis, D; Michailidis, P; Krokida, M; Loizidou, M

2016-01-01

Domestic food waste drying foresees the significant reduction of household food waste mass through the hygienic removal of its moisture content at source. In this manuscript, a new approach for the development and optimization of an innovative household waste dryer for the effective dehydration of food waste at source is presented. Food waste samples were dehydrated with the use of the heated air-drying technique under different air-drying conditions, namely air temperature and air velocity, in order to investigate their drying kinetics. Different thin-layer drying models have been applied, in which the drying constant is a function of the process variables. The Midilli model demonstrated the best performance in fitting the experimental data in all tested samples, whereas it was found that food waste drying is greatly affected by temperature and to a smaller scale by air velocity. Due to the increased moisture content of food waste, an appropriate configuration of the drying process variables can lead to a total reduction of its mass by 87% w/w, thus achieving a sustainable residence time and energy consumption level. Thus, the development of a domestic waste dryer can be proved to be economically and environmentally viable in the future.

[Separation and purification of an endogenous inhibitor of sodium pump from chansu by thin-layer chromatography and reversed-phase high performance liquid chromatography].

PubMed

Li, S Q

2001-11-01

An endogenous inhibitor of the sodium pump from the Chinese medication Chansu was purified. The dry substance Chansu was extracted with methanol. The dry residue dissolved in water and filtered subsequently through membrane filters with the exclusion size of 1000 Da, 3000 Da and 10000 Da in a Filtron Pro Vario-3-System and applied to thin-layer chromatographic plate made of Silica gel 60 F254 + 366 developed with a mixture of CHCl3-MeOH-H2O(75:20:5, volume ratio). The fractions with Rf 0.55 inhibiting the sodium pump were purified on an HPLC C18-RP column using a linear H2O-methanol gradient with 220 nm and 300 nm DAD detection. The bioactivity was measured by 86Rb-uptake into human red blood cells. The results showed that a low molecular weight, water soluble compound, which inhibited the sodium pump activity in the red blood cells and had a maximum absorbance at 250 nm was isolated from the Chinese medication Chansu. Several mg of the compound in pure state could be obtained from 1 kg Chansu. It was different from ouabain and proscillaridin A in chemical structure, because ouabain and proscillaridin A show a UV maximum absorption at 220 nm and 300 nm, while the new inhibitor at 250 nm.

A micro oxygen sensor based on a nano sol-gel TiO2 thin film.

PubMed

Wang, Hairong; Chen, Lei; Wang, Jiaxin; Sun, Quantao; Zhao, Yulong

2014-09-03

An oxygen gas microsensor based on nanostructured sol-gel TiO2 thin films with a buried Pd layer was developed on a silicon substrate. The nanostructured titania thin films for O2 sensors were prepared by the sol-gel process and became anatase after heat treatment. A sandwich TiO2 square board with an area of 350 μm × 350 μm was defined by both wet etching and dry etching processes and the wet one was applied in the final process due to its advantages of easy control for the final structure. A pair of 150 nm Pt micro interdigitated electrodes with 50 nm Ti buffer layer was fabricated on the board by a lift-off process. The sensor chip was tested in a furnace with changing the O2 concentration from 1.0% to 20% by monitoring its electrical resistance. Results showed that after several testing cycles the sensor's output becomes stable, and its sensitivity is 0.054 with deviation 2.65 × 10(-4) and hysteresis is 8.5%. Due to its simple fabrication process, the sensor has potential for application in environmental monitoring, where lower power consumption and small size are required.

A primary study into graphene/polyether ether ketone (PEEK) nanocomposite for laser sintering

NASA Astrophysics Data System (ADS)

Chen, Binling; Berretta, Silvia; Evans, Ken; Smith, Kaylie; Ghita, Oana

2018-01-01

This paper proposes two methods of preparation of graphene/PEEK powders for Laser Sintering (LS) and investigates their behaviour in relation to their microstructure and their properties. Thin composite films were fabricated in an attempt to replicate the thin layer formation of the powder bed process. Both methods of composite powder preparation (wet and dry) led to enhanced mechanical performance of the composite films at 0.1 and 0.5 wt% graphene nano-platelets (GNP) concentrations. The TEM images show that the GNP act as a nucleation point in crystallisation of PEEK, being at the centre of the spherulites. The hot stage microscopy reveals a 20 s delay in the onset of GNP/PEEK nanocomposite coalescence in comparison with plain PEEK. This is a very important observation for laser sintering, as it will influence the build strategy and specific parameters (e.g. time between layers deposition, multiple exposures). The excellent electrical conductivity properties of graphene were noticeable in the nanocomposite films at concentrations above 1 wt% GNP.

Characterizing Electric Field Exposed P3HT Thin Films Using Polarized-Light Spectroscopies

DOE PAGES

Bhattacharjee, Ujjal; Elshobaki, Moneim; Santra, Kalyan; ...

2016-06-23

P3HT (poly (3-hexylthiophene)) has been widely used as a donor in the active layer in organic photovoltaic devices. Although moderately high-power conversion efficiencies have been achieved with P3HT-based devices, structural details, such as the orientation of polymer units and the extent of H- and J-aggregation are not yet fully understood; and different measures have been taken to control the ordering in the material. One such measure, which we have exploited, is to apply an electric field from a Van de Graaff generator. We used fluorescence (to measure anisotropy instead of polarization, which is more commonly measured) and Raman spectroscopy tomore » characterize the order of P3HT molecules in thin films resulting from the field. We determine preferential orientations of the units in a thin film, consistent with observed hole mobility in thin-film-transistors, and observe that the apparent H-coupling strength changes when the films are exposed to oriented electrical fields during drying.« less

Organic Light Emitting Diodes with Opal Photonic Crystal Layer and Carbon Nanotube Anode

NASA Astrophysics Data System (ADS)

Ovalle Robles, Raquel; Del Rocio Nava, Maria; Williams, Christopher; Zhang, Mei; Fang, Shaoli; Lee, Sergey; Baughman, Ray; Zakhidov, Anvar

2007-03-01

We report electroluminescence intensity and spectral changes in light emission from organic light emitting diode (OLEDs) structures, which have thin transparent films of opal photonic crystal (PC). The anode in such PC-OLED is laminated on opal layer from free standing optically transparent multiwall carbon nanotubes (T-CNT) sheets made by dry spinning from CVD grown forests. Silica and polystyrene opal films were grown on glass substrates by vertical sedimentation in colloids in thermal baths and the particle size of opal spheres ranges from 300 nm to 450 nm. The use of T-CNTs, (coated by PEDOT-PSS to avoid shorting) as hole injector, allows to eliminate the use of vacuum deposition of metals and permits to achieve tunneling hole injection regime from CNT tips into Alq^3 emission layer

Effect of oxygen, moisture and illumination on the stability and reliability of dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) OTFTs during operation and storage.

PubMed

Ding, Ziqian; Abbas, Gamal; Assender, Hazel E; Morrison, John J; Yeates, Stephen G; Patchett, Eifion R; Taylor, D Martin

2014-09-10

We report a systemic study of the stability of organic thin film transistors (OTFTs) both in storage and under operation. Apart from a thin polystyrene buffer layer spin-coated onto the gate dielectric, the constituent parts of the OTFTs were all prepared by vacuum evaporation. The OTFTs are based on the semiconducting small molecule dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) deposited onto the surface of a polystyrene-buffered in situ polymerized diacrylate gate insulator. Over a period of 9 months, no degradation of the hole mobility occurred in devices stored either in the dark in dry air or in uncontrolled air and normal laboratory fluorescent lighting conditions. In the latter case, rather than decreasing, the mobility actually increased almost 2-fold to 1.5 cm(2)/(V · s). The devices also showed good stability during repeat on/off cycles in the dark in dry air. Exposure to oxygen and light during the on/off cycles led to a positive shift of the transfer curves due to electron trapping when the DNTT was biased into depletion by the application of positive gate voltage. When operated in accumulation, negative gate voltage under the same conditions, the transfer curves were stable. When voltage cycling in moist air in the dark, the transfer curves shifted to negative voltages, thought to be due to the generation of hole traps either in the semiconductor or its interface with the dielectric layer. When subjected to gate bias stress in dry air in the dark for at least 144 h, the device characteristics remained stable.

Influence of interfacial rheology on stabilization of the tear film

NASA Astrophysics Data System (ADS)

Bhamla, M. Saad; Fuller, Gerald G.

2014-11-01

The tear film that protecting the ocular surface is a complex, thin film comprised of a collection of proteins and lipids that come together to provide a number of important functions. Of particular interest in this presentation is meibum, an insoluble layer that is spread from glands lining our eyelids. Past work has focussed on the role of this layer in reducing evaporation, although conflicting evidence on its ability to reduce evaporative loss has been published. We present here the beneficial effects that are derived through the interfacial viscoelasticity of the meibomian lipid film. This is a duplex film is comprised of a rich mixture of phospholipids, long chain fatty esters, and cholesterol esters. Using interfacial rheology measurements, meibum has been shown to be highly viscoelastic. By measuring the drainage and dewetting dynamics of thin aqueous films from hemispherical surfaces where those films are laden with insoluble layers of lipids at controlled surface pressure, we offer evidence that these layers strongly stabilize the films because of their ability to support surface shearing stresses. This alternative view of the role of meibum can help explain the origin of meibomian gland dysfunction, or dry eye disease, where improper compositions of this lipid mixture do not offer the proper mechanical resistance to breakage and dewetting of the tear film.

Complementary microanalysis of Zn, Mn and Fe in the chelicera of spiders and scorpions using scanning MeV-ion and electron microprobes

NASA Astrophysics Data System (ADS)

Schofield, Robert; Lefevre, Harlan; Shaffer, Michael

1989-04-01

Energy-loss scanning transmission ion microscopy (ELSTIM or just STIM), PIXE and electron microprobe techniques are used to investigate certain minor element accumulations in a few spiders and scorpions. STIM and PIXE are used to survey the unsectioned specimens, while electron microprobe techniques are used for higher resolution investigations of several sections of the specimens. Concentration values measured using STIM and PIXE are found to be in satisfactory agreement with those measured using electron probe microanalysis. A garden spider Araneus diadematus is found to contain high concentrations of zinc in a thin layer near the surface of its fangs (reaching 23% of dry weight), and manganese in its marginal teeth (about 5% of dry weight). A wolf spider Alopecosa kochi is found to have similar concentrations of zinc in a layer near the surface of it's fang, and concentrations of manganese reaching 1.5% in a layer beneath the zinc containing layer. A scorpion Centruroides sp. is found to contain high concentrations of iron (reaching 8%) and zinc (reaching 24%) in the tips of teeth on the cheliceral fingers, and manganese (about 5%) in the stinger. The hypothesis that these elements simply harden the cuticle does not appear to explain their segregation patterns.

Effect of Drying Temperature on Rosmarinic Acid and Sinensetin Concentration in Orthosiphon stamineus Herbal Leaves

NASA Astrophysics Data System (ADS)

Abdullah, Sriyana; Razak Shaari, Abdul; Hajar Rukunudin, Ibni; Syarhabil Ahmad, Muhammad

2018-03-01

The objective of this work was to investigate the effects of drying temperature on the concentration of O rthosiphon stamineus biomarker compounds which were rosmarinic acid (RA) and sinensetin (SEN). The thin layer drying approach was used to dry O. stamineus leaves at various temperatures of 30, 40 and 50°C using a laboratory scale hot air dryer. The dried leaves were then extracted using 60% aqueous methanol prior to quantification. The RA and SEN concentrations in the dried leaves extracts were quantified by the high performance liquid chromatography. The concentration of RA for the dried leaves at 30 and 40°C were higher as compared to that of the fresh leaves. This may due to the response of the plant cells to abiotic stress. The concentration of RA also showed a significant reduction when the temperature was increased to 50°C. In contrast, the SEN concentration in O. stamineus dried leaf extract was lower than that of the fresh samples. The concentrations of SEN depicted insignificant effects by drying at 30 and 50°C, and the highest value was obtained in the samples dried at 40°C. Results showed that the drying process was found to affect the concentration of both compounds; therefore suitable drying conditions should be adopted to enhance the medicinal values of the plant species.

Performance of a Cross-Flow Humidifier with a High Flux Water Vapor Transport Membrane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahluwalia, R. K.; Wang, X.; Johnson, W. B.

Water vapor transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flowmore » humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower pressures, but the mass transfer effectiveness is higher at higher pressures. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the gradient in RH of the wet and dry streams but is also affected by vapor diffusion in the gas layer and the microporous layer.« less

System for analysis of explosives

DOEpatents

Haas, Jeffrey S [San Ramon, CA

2010-06-29

A system for analysis of explosives. Samples are spotted on a thin layer chromatography plate. Multi-component explosives standards are spotted on the thin layer chromatography plate. The thin layer chromatography plate is dipped in a solvent mixture and chromatography is allowed to proceed. The thin layer chromatography plate is dipped in reagent 1. The thin layer chromatography plate is heated. The thin layer chromatography plate is dipped in reagent 2.

Nanocrystalline SnO2:F Thin Films for Liquid Petroleum Gas Sensors

PubMed Central

Chaisitsak, Sutichai

2011-01-01

This paper reports the improvement in the sensing performance of nanocrystalline SnO2-based liquid petroleum gas (LPG) sensors by doping with fluorine (F). Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. The effect of F concentration on the structural, surface morphological and LPG sensing properties of the SnO2 films was investigated. Atomic Force Microscopy (AFM) and X-ray diffraction pattern measurements showed that the obtained thin films are nanocrystalline SnO2 with nanoscale-textured surfaces. Gas sensing characteristics (sensor response and response/recovery time) of the SnO2:F sensors based on a planar interdigital structure were investigated at different operating temperatures and at different LPG concentrations. The addition of fluorine to SnO2 was found to be advantageous for efficient detection of LPG gases, e.g., F-doped sensors are more stable at a low operating temperature (300 °C) with higher sensor response and faster response/recovery time, compared to un-doped sensor materials. The sensors based on SnO2:F films could detect LPG even at a low level of 25% LEL, showing the possibility of using this transparent material for LPG leak detection. PMID:22164007

Salt-assisted direct exfoliation of graphite into high-quality, large-size, few-layer graphene sheets.

PubMed

Niu, Liyong; Li, Mingjian; Tao, Xiaoming; Xie, Zhuang; Zhou, Xuechang; Raju, Arun P A; Young, Robert J; Zheng, Zijian

2013-08-21

We report a facile and low-cost method to directly exfoliate graphite powders into large-size, high-quality, and solution-dispersible few-layer graphene sheets. In this method, aqueous mixtures of graphite and inorganic salts such as NaCl and CuCl2 are stirred, and subsequently dried by evaporation. Finally, the mixture powders are dispersed into an orthogonal organic solvent solution of the salt by low-power and short-time ultrasonication, which exfoliates graphite into few-layer graphene sheets. We find that the as-made graphene sheets contain little oxygen, and 86% of them are 1-5 layers with lateral sizes as large as 210 μm(2). Importantly, the as-made graphene can be readily dispersed into aqueous solution in the presence of surfactant and thus is compatible with various solution-processing techniques towards graphene-based thin film devices.

New approach for producing chemical templates over large area by Molecular Transfer Printing

NASA Astrophysics Data System (ADS)

Inoue, Takejiro; Janes, Dustin; Ren, Jiaxing; Willson, Grant; Ellison, Christopher; Nealey, Paul

2014-03-01

Fabrication of well-defined chemically patterned surfaces is crucially important to the development of next generation microprocessors, hard disk memory devices, photonic/plasmonic devices, separation membranes, and biological microarrays. One promising patterning method in these fields is Molecular Transfer Printing (MTP), which replicates chemical patterns with feature dimensions of the order of 10nm utilizing a master template defined by the microphase separated domains of a block copolymer thin film. The total transfer printing area achievable by MTP has so far been limited by the contact area between two rigid substrates. Therefore, strategies to make conformal contact between substrates could be practically useful because a single lithographically-defined starting pattern could be used to fabricate many replicates by a low-cost process. Here we show a new approach that utilizes a chemically deposited SiN layer and a liquid conformal layer to enable transfer printing of chemical patterns upon thermal annealing over large, continuous areas. We anticipate that our process could be integrated into Step and Flash Imprint Lithography (SFIL) tools to achieve conformal layer thicknesses thin and uniform enough to permit pattern transfer through a dry-etch protocol.

Reduction of stand density as a management tool to mitigate the effect of drought

NASA Astrophysics Data System (ADS)

Giuggiola, A.; Rigling, A.; Dobbertin, M.

2012-04-01

An increasing frequency and severity of drought combined with increased competition due to reduced forest management practices are putting many Scots pine forest (Pinus sylvestris) under increased drought pressure. Declining pines are already been observed in many drought exposed regions as in southern Europe or in the dry inner Alpine valleys. Thus, forest management practices oriented at reducing competition for water should increase pines tolerance to climate change and thus enhancing their long-term mitigation potential. In this study, we are testing the beneficial effect of thinning and understory removal as possible management practices. As a first study object we selected a trial with 3 thinning intensities (basal area reduction of 15%, 46% and 70%) and one control (unmanaged forest). The second experiment consisted in removing the understory layer in a radius of 5 meter from 6 mature pine trees. Water-related indicators, such as soil water content, sapflow, point dendrometer and ring width measurements over the growing season were then compared with control trees. Both objects belongs to the pine forests from the dry Rhone valley. Our results indicates that over the 10 years following the thinning performed in 1965 (when the stand was 45 years old) doubled and quadrupled the basal area increment in the medium and heavy treatments compared to the control. The annual mortality rates for the period 1978-1990 ranged between 2.9% for the control and 0.8% for the heavy thinned stand. An increasing mortality rates during the period 1991-2009 (up to 3.3%), with consequent decline in basal area and carbon sequestration, has been observed in relation to high remaining stand density. The removal of understory performed in April 2010 increased soil water content at 30 cm and 65 cm depth reducing trees drought stress. The transpiration and the predawn leaf water potential of overstory trees were higher in the trees with removal of the understory vegetation. The same trees also showed delayed stomata closure during drought periods. This advantage eventually resulted in a significant increase in tree growth, which was observed in the second year after removal. This combining approach highlight the positive effect of competition removal of growth and vitality of Scots pine trees. Our results suggest that in dry forests of the inner-Alps or the Mediterranean region, a strong reduction of basal area (15-25 m2/ha) is suitable to preserve enough water availability to maintain and healthy state. If thinning lead to a major increase of the understory layer, understory removal would prolong the initial positive effect of thinning. Thinning and understory removal enhance tree vitality and increase tree resistance against drought, insects and pathogens. These results simultaneously suggests that pine decline is not driven only by the increase of temperature, but is also a consequence of a change of forest use, specifically for the Valais, to a reduction of goat grazing pressure and wood harvesting.

Covering surface nanobubbles with a NaCl nanoblanket.

PubMed

Berkelaar, Robin P; Zandvliet, Harold J W; Lohse, Detlef

2013-09-10

By letting a NaCl aqueous solution of low (0.01 M) concentration evaporate on a highly oriented pyrolytic graphite (HOPG) surface, it is possible to form a thin film of salt. However, pre-existing surface nanobubbles prevent the homogeneous coverage of the surface with the salt, keeping the footprint areas on the substrate pristine. Comparing the surface nanobubbles in the salt solution with their associated footprint after drying, provides information on the shrinkage of nanobubbles during the hours-long process of drying the liquid film. At a slightly higher NaCl concentration and thus salt layer thickness, the nanobubbles are covered with a thin blanket of salt. Once the liquid film has evaporated until a water film remains that is smaller than the height of the nanobubbles, the blanket of salt cracks and unfolds into a flower-like pattern of salt flakes that is located at the rim of the nanobubble footprint. The formation of a blanket of salt covering the nanobubbles is likely to considerably or even completely block the gas out-flux from the nanobubble, partially stabilizing the nanobubbles against dissolution.

Palladium-bacterial cellulose membranes for fuel cells.

PubMed

Evans, Barbara R; O'Neill, Hugh M; Malyvanh, Valerie P; Lee, Ida; Woodward, Jonathan

2003-07-01

Bacterial cellulose is a versatile renewable biomaterial that can be used as a hydrophilic matrix for the incorporation of metals into thin, flexible, thermally stable membranes. In contrast to plant cellulose, we found it catalyzed the deposition of metals within its structure to generate a finely divided homogeneous catalyst layer. Experimental data suggested that bacterial cellulose possessed reducing groups capable of initiating the precipitation of palladium, gold, and silver from aqueous solution. Since the bacterial cellulose contained water equivalent to at least 200 times the dry weight of the cellulose, it was dried to a thin membranous structure suitable for the construction of membrane electrode assemblies (MEAs). Results of our study with palladium-cellulose showed that it was capable of catalyzing the generation of hydrogen when incubated with sodium dithionite and generated an electrical current from hydrogen in an MEA containing native cellulose as the polyelectrolyte membrane (PEM). Advantages of using native and metallized bacterial cellulose membranes in an MEA over other PEMs such as Nafion 117 include its higher thermal stability to 130 degrees C and lower gas crossover.

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

Code of Federal Regulations, 2010 CFR

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 inert...

Method of transferring a thin crystalline semiconductor layer

DOEpatents

Nastasi, Michael A [Sante Fe, NM; Shao, Lin [Los Alamos, NM; Theodore, N David [Mesa, AZ

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.

Drying Temperature Dependence of Sol-gel Spin Coated Bilayer Composite ZnO/TiO2 Thin Films for Extended Gate Field Effect Transistor pH Sensor

NASA Astrophysics Data System (ADS)

Rahman, R. A.; Zulkefle, M. A.; Yusoff, K. A.; Abdullah, W. F. H.; Rusop, M.; Herman, S. H.

2018-03-01

This study presents an investigation on zinc oxide (ZnO) and titanium dioxide (TiO2) bilayer film applied as the sensing membrane for extended-gate field effect transistor (EGFET) for pH sensing application. The influences of the drying temperatures on the pH sensing capability of ZnO/TiO2 were investigated. The sensing performance of the thin films were measured by connecting the thin film to a commercial MOSFET to form the extended gates. By varying the drying temperature, we found that the ZnO/TiO2 thin film dried at 150°C gave the highest sensitivity compared to other drying conditions, with the sensitivity value of 48.80 mV/pH.

Triboelectric generator

DOEpatents

Wang, Zhong L; Fan, Fengru; Lin, Long; Zhu, Guang; Pan, Caofeng; Zhou, Yusheng

2015-11-03

A generator includes a thin first contact charging layer and a thin second contact charging layer. The thin first contact charging layer includes a first material that has a first rating on a triboelectric series. The thin first contact charging layer has a first side with a first conductive electrode applied thereto and an opposite second side. The thin second contact charging layer includes a second material that has a second rating on a triboelectric series that is more negative than the first rating. The thin first contact charging layer has a first side with a first conductive electrode applied thereto and an opposite second side. The thin second contact charging layer is disposed adjacent to the first contact charging layer so that the second side of the second contact charging layer is in contact with the second side of the first contact charging layer.

Effect of the co-spun anode functional layer on the performance of the direct-methane microtubular solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Meng, Xiuxia; Gong, Xun; Yin, Yimei; Yang, Naitao; Tan, Xiaoyao; Ma, Zi-Feng

2014-02-01

NiO-YSZ/porous YSZ (NiO-YSZ/p-YSZ) dual-layer hollow fibers have been fabricated by a co-spinning-sintering method, on which a dense YSZ films has been formed by a dip-coating and sintering process. A LSM-YSZ ink has been dip-coated on the dense YSZ films as cathode, while the Cu-CeO2 carbon-resistant catalyst has been impregnated in the p-YSZ layer to form double-anode supported micro tubular fuel cells (MT-SOFCs). The thickness of the Ni-YSZ layer, so called anode functional layer (AFL), is controlled from 74 μm to 13 μm by varying the spinning rates of the NiO-YSZ dopes. The maximum power density of an MT-SOFC, which is fabricated based on a thin co-spun AFL, reaches 566 mW cm-2 operated at 850 °C fed with dry methane, and is stably operated for 85 h without power declination.

Refractive index sensing in the visible/NIR spectrum using silicon nanopillar arrays.

PubMed

Visser, D; Choudhury, B Dev; Krasovska, I; Anand, S

2017-05-29

Si nanopillar (NP) arrays are investigated as refractive index sensors in the visible/NIR wavelength range, suitable for Si photodetector responsivity. The NP arrays are fabricated by nanoimprint lithography and dry etching, and coated with thin dielectric layers. The reflectivity peaks obtained by finite-difference time-domain (FDTD) simulations show a linear shift with coating layer thickness. At 730 nm wavelength, sensitivities of ~0.3 and ~0.9 nm/nm of SiO 2 and Si 3 N 4 , respectively, are obtained; and the optical thicknesses of the deposited surface coatings are determined by comparing the experimental and simulated data. The results show that NP arrays can be used for sensing surface bio-layers. The proposed method could be useful to determine the optical thickness of surface coatings, conformal and non-conformal, in NP-based optical devices.

Combinatorial screening of halide perovskite thin films and solar cells by mask-defined IR laser molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Kawashima, Kazuhiro; Okamoto, Yuji; Annayev, Orazmuhammet; Toyokura, Nobuo; Takahashi, Ryota; Lippmaa, Mikk; Itaka, Kenji; Suzuki, Yoshikazu; Matsuki, Nobuyuki; Koinuma, Hideomi

2017-12-01

As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic-inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH3NH3I) and inorganic halide (B-site: PbI2) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I-V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI2 and CH3NH3I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell.

Combinatorial screening of halide perovskite thin films and solar cells by mask-defined IR laser molecular beam epitaxy.

PubMed

Kawashima, Kazuhiro; Okamoto, Yuji; Annayev, Orazmuhammet; Toyokura, Nobuo; Takahashi, Ryota; Lippmaa, Mikk; Itaka, Kenji; Suzuki, Yoshikazu; Matsuki, Nobuyuki; Koinuma, Hideomi

2017-01-01

As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic-inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH 3 NH 3 I) and inorganic halide (B-site: PbI 2 ) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I - V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI 2 and CH 3 NH 3 I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell.

Electrochemical Measurement of Atmospheric Corrosion

NASA Technical Reports Server (NTRS)

DeArmond, Anna H.; Davis, Dennis D.; Beeson, Harold D.

1999-01-01

Corrosion of Shuttle thruster components in atmospheres containing high concentrations of nitrogen tetroxide (NTO) and water is an important issue in ground operations of bipropellant systems in humid locations. Measurements of the corrosivities of NTO-containing atmospheres and the responses of different materials to these atmospheres have been accomplished using an electrochemical sensor. The sensor is composed of alternating aluminum/titanium strips separated by thin insulating layers. Under high humidity conditions a thin film of water covers the surface of the sensor. Added NTO vapor reacts with the water film to form a conductive medium and establishes a galvanic cell. The current from this cell can be integrated with respect to time and related to the corrosion activity. The surface layer formed from humid air/NTO reacts in the same way as an aqueous solution of nitric acid. Nitric acid is generally considered an important agent in NTO corrosion situations. The aluminum/titanium sensor is unresponsive to dry air, responds slightly to humid air (> 75% RH), and responds strongly to the combination of humid air and NTO. The sensor response is a power function (n = 2) of the NTO concentration. The sensor does not respond to NTO in dry air. The response of other materials in this type of sensor is related to position of the material in a galvanic series in aqueous nitric acid. The concept and operation of this electrochemical corrosion measurement is being applied to other corrosive atmospheric contaminants such as hydrogen chloride, hydrogen fluoride, sulfur dioxide, and acidic aerosols.

Thin films of fullerene-like MoS2 nanoparticles with ultra-low friction and wear

PubMed

Chhowalla; Amaratunga

2000-09-14

The tribological properties of solid lubricants such as graphite and the metal dichalcogenides MX2 (where M is molybdenum or tungsten and X is sulphur or selenium) are of technological interest for reducing wear in circumstances where liquid lubricants are impractical, such as in space technology, ultra-high vacuum or automotive transport. These materials are characterized by weak interatomic interactions (van der Waals forces) between their layered structures, allowing easy, low-strength shearing. Although these materials exhibit excellent friction and wear resistance and extended lifetime in vacuum, their tribological properties remain poor in the presence of humidity or oxygen, thereby limiting their technological applications in the Earth's atmosphere. But using MX2 in the form of isolated inorganic fullerene-like hollow nanoparticles similar to carbon fullerenes and nanotubes can improve its performance. Here we show that thin films of hollow MoS2 nanoparticles, deposited by a localized high-pressure arc discharge method, exhibit ultra-low friction (an order of magnitude lower than for sputtered MoS2 thin films) and wear in nitrogen and 45% humidity. We attribute this 'dry' behaviour in humid environments to the presence of curved S-Mo-S planes that prevent oxidation and preserve the layered structure.

A Micro Oxygen Sensor Based on a Nano Sol-Gel TiO2 Thin Film

PubMed Central

Wang, Hairong; Chen, Lei; Wang, Jiaxin; Sun, Quantao; Zhao, Yulong

2014-01-01

An oxygen gas microsensor based on nanostructured sol-gel TiO2 thin films with a buried Pd layer was developed on a silicon substrate. The nanostructured titania thin films for O2 sensors were prepared by the sol-gel process and became anatase after heat treatment. A sandwich TiO2 square board with an area of 350 μm × 350 μm was defined by both wet etching and dry etching processes and the wet one was applied in the final process due to its advantages of easy control for the final structure. A pair of 150 nm Pt micro interdigitated electrodes with 50 nm Ti buffer layer was fabricated on the board by a lift-off process. The sensor chip was tested in a furnace with changing the O2 concentration from 1.0% to 20% by monitoring its electrical resistance. Results showed that after several testing cycles the sensor's output becomes stable, and its sensitivity is 0.054 with deviation 2.65 × 10−4 and hysteresis is 8.5%. Due to its simple fabrication process, the sensor has potential for application in environmental monitoring, where lower power consumption and small size are required. PMID:25192312

Thin films of fullerene-like MoS2 nanoparticles with ultra-low friction and wear

NASA Astrophysics Data System (ADS)

Chhowalla, Manish; Amaratunga, Gehan A. J.

2000-09-01

The tribological properties of solid lubricants such as graphite and the metal dichalcogenides MX2 (where M is molybdenum or tungsten and X is sulphur or selenium) are of technological interest for reducing wear in circumstances where liquid lubricants are impractical, such as in space technology, ultra-high vacuum or automotive transport. These materials are characterized by weak interatomic interactions (van der Waals forces) between their layered structures, allowing easy, low-strength shearing. Although these materials exhibit excellent friction and wear resistance and extended lifetime in vacuum, their tribological properties remain poor in the presence of humidity or oxygen, thereby limiting their technological applications in the Earth's atmosphere. But using MX2 in the form of isolated inorganic fullerene-like hollow nanoparticles similar to carbon fullerenes and nanotubes can improve its performance. Here we show that thin films of hollow MoS2 nanoparticles, deposited by a localized high-pressure arc discharge method, exhibit ultra-low friction (an order of magnitude lower than for sputtered MoS2 thin films) and wear in nitrogen and 45% humidity. We attribute this `dry' behaviour in humid environments to the presence of curved S-Mo-S planes that prevent oxidation and preserve the layered structure.

Analysis of Zinc Oxide Thin Films Synthesized by Sol-Gel via Spin Coating

NASA Astrophysics Data System (ADS)

Wolgamott, Jon Carl

Transparent conductive oxides are gaining an increasingly important role in optoelectronic devices such as solar cells. Doped zinc oxide is a candidate as a low cost and nontoxic alternative to tin doped indium oxide. Lab results have shown that both n-type and p-type zinc oxide can be created on a small scale. This can allow zinc oxide to be used as either an electrode as well as a buffer layer to increase efficiency and protect the active layer in solar cells. Sol-gel synthesis is emerging as a low temperature, low cost, and resource efficient alternative to producing transparent conducting oxides such as zinc oxide. For sol-gel derived zinc oxide thin films to reach their potential, research in this topic must continue to optimize the known processing parameters and expand to new parameters to tighten control and create novel processing techniques that improve performance. The processing parameters of drying and annealing temperatures as well as cooling rate were analyzed to see their effect on the structure of the prepared zinc oxide thin films. There were also preliminary tests done to modify the sol-gel process to include silver as a dopant to produce a p-type thin film. The results from this work show that the pre- and post- heating temperatures as well as the cooling rate all play their own unique role in the crystallization of the film. Results from silver doping show that more work needs to be done to create a sol-gel derived p-type zinc oxide thin film.

Temperature Regulation of Growth and Endogenous Abscisic Acid-like Content of Tulipa gesneriana L

PubMed Central

Aung, Louis H.; De Hertogh, August A.

1979-01-01

The ontogenetic changes of dry matter and abscisic acid (ABA)-like content in the component organs of Tulipa gesneriana L. `Paul Richter' and `Golden Melody' under two temperature storage regimes were determined. The organ dry matter and ABA showed marked differences during 13 and 5 C dry storage and during subsequent growth at 13 C. Scale dry matter of both cultivars declined sharply when grown at 13 C. The basalplate of the cultivars showed an initial gain in dry matter, but declined subsequently. The shoot of both cultivars stored at 13 C exhibited greater dry matter gain than at 5 C. In contrast, the bulblets of the cultivars at 5 C showed a much higher rate of dry matter accumulation than at 13 C. An inhibitory substance extracted from tulip bulb organs co-chromatographed with authentic ABA and had identical thin layer chromatographic RF values of ABA in five solvent systems. The total ABA content per bulb increased 3-fold in `Golden Melody' and 2- to 4-fold in `Paul Richter' during the course of the temperature treatments. ABA was low in the scales and shoot, but it was high in the basalplate, bulblets, and roots. It is suggested that the probable ABA biosynthetic sites of tulip bulb are the developing bulblets, basalplate, and roots. PMID:16660867

Influence of smectite suspension structure on sheet orientation in dry sediments: XRD and AFM applications.

PubMed

Zbik, Marek S; Frost, Ray L

2010-06-15

The structure-building phenomena within clay aggregates are governed by forces acting between clay particles. Measurements of such forces are important to understand in order to manipulate the aggregate structure for applications such as dewatering of mineral processing tailings. A parallel particle orientation is required when conducting XRD investigation on the oriented samples and conduct force measurements acting between basal planes of clay mineral platelets using atomic force microscopy (AFM). To investigate how smectite clay platelets were oriented on silicon wafer substrate when dried from suspension range of methods like SEM, XRD and AFM were employed. From these investigations, we conclude that high clay concentrations and larger particle diameters (up to 5 microm) in suspension result in random orientation of platelets in the substrate. The best possible laminar orientation in the clay dry film, represented in the XRD 001/020 intensity ratio of 47 was obtained by drying thin layers from 0.02 wt.% clay suspensions of the natural pH. Conducted AFM investigations show that smectite studied in water based electrolytes show very long-range repulsive forces lower in strength than electrostatic forces from double-layer repulsion. It was suggested that these forces may have structural nature. Smectite surface layers rehydrate in water environment forms surface gel with spongy and cellular texture which cushion approaching AFM probe. This structural effect can be measured in distances larger than 1000 nm from substrate surface and when probe penetrate this gel layer, structural linkages are forming between substrate and clay covered probe. These linkages prevent subsequently smooth detachments of AFM probe on way back when retrieval. This effect of tearing new formed structure apart involves larger adhesion-like forces measured in retrieval. It is also suggested that these effect may be enhanced by the nano-clay particles interaction. 2010 Elsevier Inc. All rights reserved.

Pharmacognostic Specification, Chlorogenic Acid Content, and In vitro Antioxidant Activities of Lonicera japonica Flowering Bud.

PubMed

Chaowuttikul, Chayanon; Palanuvej, Chanida; Ruangrungsi, Nijsiri

2017-01-01

Lonicera japonica Thunb. or Japanese Honeysuckle has been widely used in traditional medicine for antipyretic. To establish the pharmacognostic specification of L. japonica flowering bud in Thailand and to determine its chlorogenic acid content and in vitro antioxidant activities. Dried L. japonica flowering bud from 15 various herbal drugstores throughout Thailand were investigated for pharmacognostic specification. Their chlorogenic acid contents were quantitatively analyzed by thin layer chromatography (TLC) densitometry with winCATS software. The mobile phase for TLC development consisted of ethyl acetate: formic acid: acetic acid: water (10:1.1:1.1:2.6). Antioxidant activities were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric ion reducing antioxidant power assay, nitric oxide scavenging assay, and β-carotene bleaching assays. Qualified L. japonica flowering bud in Thailand was presented that the contents of loss on drying, total ash, acid-insoluble ash, and water should not be >10.11%, 6.59%, 1.14%, and 10.82% by weight, respectively. The ethanol and water soluble extractive values should not be < 16.46% and 28.88% by weight, respectively. Chlorogenic acid content in L. japonica flowering bud was found to be 2.24 ± 0.50 g/100 g of crude drug. L. japonica flowering bud showed DPPH and nitric oxide scavenging activities as well as reducing power property. This pharmacognostic specification with special reference to the chlorogenic acid content can be used for quality control of L. japonica flowering bud in Thailand. The potential antioxidant of this crude drug was demonstrated in vitro . Pharmacognostic specification of Lonicera japonica flowering bud in Thailand has been establishedThe chlorogenic acid content has been quantified by thin layer chromatography-densitometryThe ethanolic extract of L. japonica flowering bud showed antioxidation potential, especially on reducing power property. Abbreviations Used: TLC: Thin layer chromatography, DPPH: 2,2-diphenyl-1-picrylhydrazyl, FRAP: Ferric ion Reducing Antioxidant Power, WHO: World Health Organization, ICH: International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use; LOD: Limit of detection; LOQ: Limit of quantitation; BHT: Butylated hydroxytoluene; FeSO 4 : Iron(II) sulfate; DMSO: Dimethyl sulfoxide; TPTZ: 2,4,6-tripyridyl-s-triazine.

Solvent-based and solvent-free characterization of low solubility and low molecular weight polyamides by mass spectrometry: a complementary approach.

PubMed

Barrère, Caroline; Hubert-Roux, Marie; Lange, Catherine M; Rejaibi, Majed; Kebir, Nasreddine; Désilles, Nicolas; Lecamp, Laurence; Burel, Fabrice; Loutelier-Bourhis, Corinne

2012-06-15

Polyamides (PA) belong to the most used classes of polymers because of their attractive chemical and mechanical properties. In order to monitor original PA design, it is essential to develop analytical methods for the characterization of these compounds that are mostly insoluble in usual solvents. A low molecular weight polyamide (PA11), synthesized with a chain limiter, has been used as a model compound and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In the solvent-based approach, specific solvents for PA, i.e. trifluoroacetic acid (TFA) and hexafluoroisopropanol (HFIP), were tested. Solvent-based sample preparation methods, dried-droplet and thin layer, were optimized through the choice of matrix and salt. Solvent-based (thin layer) and solvent-free methods were then compared for this low solubility polymer. Ultra-high-performance liquid chromatography/electrospray ionization (UHPLC/ESI)-TOF-MS analyses were then used to confirm elemental compositions through accurate mass measurement. Sodium iodide (NaI) and 2,5-dihydroxybenzoic acid (2,5-DHB) are, respectively, the best cationizing agent and matrix. The dried-droplet sample preparation method led to inhomogeneous deposits, but the thin-layer method could overcome this problem. Moreover, the solvent-free approach was the easiest and safest sample preparation method giving equivalent results to solvent-based methods. Linear as well as cyclic oligomers were observed. Although the PA molecular weights obtained by MALDI-TOF-MS were lower than those obtained by (1)H NMR and acido-basic titration, this technique allowed us to determine the presence of cyclic and linear species, not differentiated by the other techniques. TFA was shown to induce modification of linear oligomers that permitted cyclic and linear oligomers to be clearly highlighted in spectra. Optimal sample preparation conditions were determined for the MALDI-TOF-MS analysis of PA11, a model of polyamide analogues. The advantages of the solvent-free and solvent-based approaches were shown. Molecular weight determination using MALDI was discussed. Copyright © 2012 John Wiley & Sons, Ltd.

Membrane catalyst layer for fuel cells

DOEpatents

Wilson, Mahlon S.

1993-01-01

A gas reaction fuel cell incorporates a thin catalyst layer between a solid polymer electrolyte (SPE) membrane and a porous electrode backing. The catalyst layer is preferably less than about 10 .mu.m in thickness with a carbon supported platinum catalyst loading less than about 0.35 mgPt/cm.sup.2. The film is formed as an ink that is spread and cured on a film release blank. The cured film is then transferred to the SPE membrane and hot pressed into the surface to form a catalyst layer having a controlled thickness and catalyst distribution. Alternatively, the catalyst layer is formed by applying a Na.sup.+ form of a perfluorosulfonate ionomer directly to the membrane, drying the film at a high temperature, and then converting the film back to the protonated form of the ionomer. The layer has adequate gas permeability so that cell performance is not affected and has a density and particle distribution effective to optimize proton access to the catalyst and electronic continuity for electron flow from the half-cell reaction occurring at the catalyst.

Genesis of Bénard-Marangoni Patterns in Thin Liquid Films Drying into Air

NASA Astrophysics Data System (ADS)

Colinet, P.; Chauvet, F.; Dehaeck, S.

Inspired by many years of motivating collaboration between the first author and Prof. Manuel G. Velarde, in the field of surface-tension-driven instabilities, pattern formation, and transition to turbulence, this paper presents recent experimental results obtained in collaboration with the second and third authors at the TIPs laboratory in Brussels. Namely, the evolution of Bénard-like patterns is explored for pure liquid layers evaporating into air, from chaotic regimes down to more stable structures with predominant hexagonal symmetry. Drying liquid layers indeed appear as a particularly simple example of system where, due to the decreasing liquid depth, the preferred wavelength of the pattern is continuously decreased in time, hence requiring perpetual creation of new convective cells. Such pattern "genesis" appears to lead to disordered structures with interesting characteristics, whose preliminary experimental investigation is carried out here. This paper is dedicated to Prof. Manuel G. Velarde, at the occasion of his 70th birthday, as a mark of deep gratitude for all positive scientific and cultural influences he had and he still has on many young scientists.

Low stress polysilicon film and method for producing same

NASA Technical Reports Server (NTRS)

Heuer, Arthur H. (Inventor); Kahn, Harold (Inventor); Yang, Jie (Inventor)

2001-01-01

Multi-layer assemblies of polysilicon thin films having predetermined stress characteristics and techniques for forming such assemblies are disclosed. In particular, a multi-layer assembly of polysilicon thin film may be produced that has a stress level of zero, or substantially so. The multi-layer assemblies comprise at least one constituent thin film having a tensile stress and at least one constituent thin film having a compressive stress. The thin films forming the multi-layer assemblies may be disposed immediately adjacent to one another without the use of intermediate layers between the thin films.

Low stress polysilicon film and method for producing same

NASA Technical Reports Server (NTRS)

Heuer, Arthur H. (Inventor); Kahn, Harold (Inventor); Yang, Jie (Inventor)

2002-01-01

Multi-layer assemblies of polysilicon thin films having predetermined stress characteristics and techniques for forming such assemblies are disclosed. In particular, a multi-layer assembly of polysilicon thin film may be produced that has a stress level of zero, or substantially so. The multi-layer assemblies comprise at least one constituent thin film having a tensile stress and at least one constituent thin film having a compressive stress. The thin films forming the multi-layer assemblies may be disposed immediately adjacent to one another without the use of intermediate layers between the thin films.

The Foote House (10-AA-96), An Historic Archaeological Complex in the Boise River Canyon, Idaho.

DTIC Science & Technology

1982-01-01

into four or perhaps five basic rooms, three of which opened into one another (Paul 1972:293). The main front entrance faced west, and consisted of low...sediments were dry screened through 1/4 in. hardward mesh. Four areas in or adjacent to the Foote House were tested to provide structural and (if possible...down into the soil matrix through the first excavation level, to 10 cm depth. At this level, in the northwest quadrant of the unit, a thin layer of

Development towards compact nitrocellulose interferometric biochips for dry eye diagnosis based on MMP9, S100A6 and CST4 biomarkers using a Point-of-Care device

NASA Astrophysics Data System (ADS)

Santamaría, Beatriz; Laguna, María. Fe; López-Romero, David; López-Hernandez, A.; Sanza, F. J.; Lavín, A.; Casquel, R.; Maigler, M.; Holgado, M.

2018-02-01

A novel compact optical biochip based on a thin layer-sensing BICELL surface of nitrocellulose is used for in-situ labelfree detection of dry eye disease (DED). In this work the development of a compact biosensor that allows obtaining quantitative diagnosis with a limited volume of sample is reported. The designed sensors can be analyzed with an optical integrated Point-of-Care read-out system based on the "Increase Relative Optical Power" principle which enhances the performance and Limit of Detection. Several proteins involved with dry eye dysfunction have been validated as biomarkers. Presented biochip analyzes three of those biomarkers: MMP9, S100A6 and CST4. BICELLs based on nitrocellulose permit to immobilize antibodies for each biomarker recognition. The optical response obtained from the biosensor through the readout platform is capable to recognize specifically the desired proteins in the concentrations range for control eye (CE) and dry eye syndrome (DES). Preliminary results obtained will allow the development of a dry eye detection device useful in the area of ophthalmology and applicable to other possible diseases related to the eye dysfunction.

Patch testing with thin-layer chromatograms of chamomile tea in patients allergic to sesquiterpene lactones.

PubMed

Lundh, Kerstin; Gruvberger, Birgitta; Möller, Halvor; Persson, Lena; Hindsén, Monica; Zimerson, Erik; Svensson, Ake; Bruze, Magnus

2007-10-01

Patients with contact allergy to sesquiterpene lactones (SLs) are usually hypersensitive to Asteraceae plant products such as herbal teas. The objective of this study was to show sensitizers in chamomile tea by patch testing with thin-layer chromatograms. Tea made from German chamomile was separated by thin-layer chromatography. Strips of the thin-layer chromatograms were used for patch testing SL-positive patients. 15 (43%) of 35 patients tested positively to 1 or more spots on the thin-layer chromatogram, with many individual reaction patterns. Patch testing with thin-layer chromatograms of German chamomile tea showed the presence of several allergens.

Few layer epitaxial germanene: a novel two-dimensional Dirac material

NASA Astrophysics Data System (ADS)

Dávila, María Eugenia; Le Lay, Guy

2016-02-01

Monolayer germanene, a novel graphene-like germanium allotrope akin to silicene has been recently grown on metallic substrates. Lying directly on the metal surfaces the reconstructed atom-thin sheets are prone to lose the massless Dirac fermion character and unique associated physical properties of free standing germanene. Here, we show that few layer germanene, which we create by dry epitaxy on a gold template, possesses Dirac cones thanks to a reduced interaction. This finding established on synchrotron-radiation-based photoemission, scanning tunneling microscopy imaging and surface electron diffraction places few layer germanene among the rare two-dimensional Dirac materials. Since germanium is currently used in the mainstream Si-based electronics, perspectives of using germanene for scaling down beyond the 5 nm node appear very promising. Other fascinating properties seem at hand, typically the robust quantum spin Hall effect for applications in spintronics and the engineering of Floquet Majorana fermions by light for quantum computing.

Few layer epitaxial germanene: a novel two-dimensional Dirac material.

PubMed

Dávila, María Eugenia; Le Lay, Guy

2016-02-10

Monolayer germanene, a novel graphene-like germanium allotrope akin to silicene has been recently grown on metallic substrates. Lying directly on the metal surfaces the reconstructed atom-thin sheets are prone to lose the massless Dirac fermion character and unique associated physical properties of free standing germanene. Here, we show that few layer germanene, which we create by dry epitaxy on a gold template, possesses Dirac cones thanks to a reduced interaction. This finding established on synchrotron-radiation-based photoemission, scanning tunneling microscopy imaging and surface electron diffraction places few layer germanene among the rare two-dimensional Dirac materials. Since germanium is currently used in the mainstream Si-based electronics, perspectives of using germanene for scaling down beyond the 5 nm node appear very promising. Other fascinating properties seem at hand, typically the robust quantum spin Hall effect for applications in spintronics and the engineering of Floquet Majorana fermions by light for quantum computing.

Few layer epitaxial germanene: a novel two-dimensional Dirac material

PubMed Central

Dávila, María Eugenia; Le Lay, Guy

2016-01-01

Monolayer germanene, a novel graphene-like germanium allotrope akin to silicene has been recently grown on metallic substrates. Lying directly on the metal surfaces the reconstructed atom-thin sheets are prone to lose the massless Dirac fermion character and unique associated physical properties of free standing germanene. Here, we show that few layer germanene, which we create by dry epitaxy on a gold template, possesses Dirac cones thanks to a reduced interaction. This finding established on synchrotron-radiation-based photoemission, scanning tunneling microscopy imaging and surface electron diffraction places few layer germanene among the rare two-dimensional Dirac materials. Since germanium is currently used in the mainstream Si-based electronics, perspectives of using germanene for scaling down beyond the 5 nm node appear very promising. Other fascinating properties seem at hand, typically the robust quantum spin Hall effect for applications in spintronics and the engineering of Floquet Majorana fermions by light for quantum computing. PMID:26860590

Amorphous silicon Schottky barrier solar cells incorporating a thin insulating layer and a thin doped layer

DOEpatents

Carlson, David E.

1980-01-01

Amorphous silicon Schottky barrier solar cells which incorporate a thin insulating layer and a thin doped layer adjacent to the junction forming metal layer exhibit increased open circuit voltages compared to standard rectifying junction metal devices, i.e., Schottky barrier devices, and rectifying junction metal insulating silicon devices, i.e., MIS devices.

Fucoxanthin from brown seaweed Sargassum cristaefolium tea in acid pH

NASA Astrophysics Data System (ADS)

Kartikaningsih, Hartati; Mufti, Eka Deviana; Nurhanief, Ardian Eko

2017-05-01

Dried tea Sargassum cristaefolium contains the pigment fucoxanthin, which is responsible for the red-orange color found in brown algae, and is a kind of photosynthetic pigment. Fucoxanthin can be used as an anti-obesity, anticancer, anti-cholesterol, and anti-diabetic agent and as a food colorant, but it is very unstable. The aim of this research was to determine the stability of fucoxanthin from dried tea brown algae at different pH (2, 6). This involved thin layer chromatography, peak absorption, wavelength analysis and reposition in FTIR. The research showed that fucoxanthin from fresh and dried tea Sargassum cristaefolium using chromatography columns had an orange color, Rf value of 0.26-0.28, and a spectral pattern in acetone solvent of 446.3-447.4 λmax. Fucoxanthin at pH 2 showed that there was no allenic group, as fucoxanthin solution had a pale yellow color. It is therefore shown that fucoxanthin is not stable in acid solution.

Quantification and characterisation of fatty acid methyl esters in microalgae: Comparison of pretreatment and purification methods.

PubMed

Lage, Sandra; Gentili, Francesco G

2018-06-01

A systematic qualitative and quantitative analysis of fatty acid methyl esters (FAMEs) is crucial for microalgae species selection for biodiesel production. The aim of this study is to identify the best method to assess microalgae FAMEs composition and content. A single-step method, was tested with and without purification steps-that is, separation of lipid classes by thin-layer chromatography (TLC) or solid-phase extraction (SPE). The efficiency of a direct transesterification method was also evaluated. Additionally, the yield of the FAMEs and the profiles of the microalgae samples with different pretreatments (boiled in isopropanol, freezing, oven-dried and freeze-dried) were compared. The application of a purification step after lipid extraction proved to be essential for an accurate FAMEs characterisation. The purification methods, which included TLC and SPE, provided superior results compared to not purifying the samples. Freeze-dried microalgae produced the lowest FAMEs yield. However, FAMEs profiles were generally equivalent among the pretreatments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of channel thickness on oxide thin film transistor with double-stacked channel layer

NASA Astrophysics Data System (ADS)

Lee, Kimoon; Kim, Yong-Hoon; Yoon, Sung-Min; Kim, Jiwan; Oh, Min Suk

2017-11-01

To improve the field effect mobility and control the threshold voltage ( V th ) of oxide thin film transistors (TFTs), we fabricated the oxide TFTs with double-stacked channel layers which consist of thick Zn-Sn-O (ZTO) and very thin In-Zn-O (IZO) layers. We investigated the effects of the thickness of thin conductive layer and the conductivity of thick layer on oxide TFTs with doublestacked channel layer. When we changed the thickness of thin conductive IZO channel layer, the resistivity values were changed. This resistivity of thin channel layer affected on the saturation field effect mobility and the off current of TFTs. In case of the thick ZTO channel layer which was deposited by sputtering in Ar: O2 = 10: 1, the device showed better performances than that which was deposited in Ar: O2 = 1: 1. Our TFTs showed high mobility ( μ FE ) of 40.7 cm2/Vs and V th of 4.3 V. We assumed that high mobility and the controlled V th were caused by thin conductive IZO layer and thick stable ZTO layer. Therefore, this double-stacked channel structure can be very promising way to improve the electrical characteristics of various oxide thin film transistors.

Comparative Physicochemical Evaluation of Kharekhasak (Tribulus terrestris Linn.) Before and After Mudabbar Process

PubMed Central

Tauheed, Abdullah; Hamiduddin; Khanam, Salma; Ali, Mohd Akhtar; Zaigham, Mohammad

2017-01-01

Background and Objectives: Mudabbar/Tadbeere advia is referred to the processes performed on the drugs to detoxify, purify, and enhance therapeutic action and to reduce its doses before making the formulations in Unani medicine. It improves quality of drugs either by optimizing its desirable characteristics or minimizing the undesirable ones; it makes drug effective, safe, and specific. There is a need of comparative evaluation to understand its significance. Tadbeer of Kharekhasak (KK) khurd (Tribulus terrestris Linn. fruit) is described by Rabban Al-Tabari in Firdausul Hikmat, Akbar Arzani in Qarabadeene Qadri, etc., during the compounding of aphrodisiac formulations. Mudabbar Kharekhasak (MKK) used in Safoofe Kharekhasak mentioned in Al-Qarabadeene was evaluated in this work. Methods: Mudabbar/Tadbeer process was carried out by blending fresh KK. Juice with powdered dry KK and drying it under the sun. Juice used for process is thrice the weight of dry KK powder. The KK before and after the process was evaluated using physicochemical tests: powder characterization, extractive value, alcohol and water soluble matter, ash value, loss on drying (LOD) at 105°C, pH, high-performance thin layer chromatography (HPTLC) fingerprinting, and diosgenin content. Results: Powder characterizations were set in. Increase in successive and nonsuccessive extractive values in various solvents, water/alcohol-soluble content, total ash, acid-insoluble ash, water-soluble ash, and sulfated ash of MKK was noted in comparison with KK. Decrease in LOD at 105°C and pH of MKK powder was observed. HPTLC fingerprinting data were developed for the identification and evaluation. Quantification of diosgenin content increased to 432.1 g/g in MKK as compared to 144.5 g/g in KK, suggesting significant increase in saponin content. Conclusion: Data obtained clearly indicated changes in MKK validating the classical Mudabbar process, probably to enhance/modify the action of drug. Standards for crude and MKK were established for future reference. SUMMARY Mudabbar process on Tribulus terrestris Linn (KK) havebeen validated.Physicochemical data for Mudabbar and non mudabbar Kharekhasak (KK) powder have been set in.Diosgenin content was increased significantly in mudabbar KK. Abbreviations Used: KK: Kharekhasak, TT: Tribulus terrestris, MKK: mudabbar Kharekhasak, SK: Safoofe Kharekhasak, LOD: loss of weight on drying, HPTLC: High performance thin layer chromatography, BSS: British standard sieve, μl: microliter, SEM: Standard error of mean, nm: nanometer, g: gram. PMID:29263633

Comparative Physicochemical Evaluation of Kharekhasak (Tribulus terrestris Linn.) Before and After Mudabbar Process.

PubMed

Tauheed, Abdullah; Hamiduddin; Khanam, Salma; Ali, Mohd Akhtar; Zaigham, Mohammad

2017-01-01

Mudabbar/ Tadbeere advia is referred to the processes performed on the drugs to detoxify, purify, and enhance therapeutic action and to reduce its doses before making the formulations in Unani medicine. It improves quality of drugs either by optimizing its desirable characteristics or minimizing the undesirable ones; it makes drug effective, safe, and specific. There is a need of comparative evaluation to understand its significance. Tadbeer of Kharekhasak (KK) khurd ( Tribulus terrestris Linn. fruit) is described by Rabban Al-Tabari in Firdausul Hikmat, Akbar Arzani in Qarabadeene Qadri, etc., during the compounding of aphrodisiac formulations. Mudabbar Kharekhasak (MKK) used in Safoofe Kharekhasak mentioned in Al-Qarabadeene was evaluated in this work. Mudabbar/Tadbeer process was carried out by blending fresh KK. Juice with powdered dry KK and drying it under the sun. Juice used for process is thrice the weight of dry KK powder. The KK before and after the process was evaluated using physicochemical tests: powder characterization, extractive value, alcohol and water soluble matter, ash value, loss on drying (LOD) at 105°C, pH, high-performance thin layer chromatography (HPTLC) fingerprinting, and diosgenin content. Powder characterizations were set in. Increase in successive and nonsuccessive extractive values in various solvents, water/alcohol-soluble content, total ash, acid-insoluble ash, water-soluble ash, and sulfated ash of MKK was noted in comparison with KK. Decrease in LOD at 105°C and pH of MKK powder was observed. HPTLC fingerprinting data were developed for the identification and evaluation. Quantification of diosgenin content increased to 432.1 g/g in MKK as compared to 144.5 g/g in KK, suggesting significant increase in saponin content. Data obtained clearly indicated changes in MKK validating the classical Mudabbar process, probably to enhance/modify the action of drug. Standards for crude and MKK were established for future reference. Mudabbar process on Tribulus terrestris Linn (KK) havebeen validated.Physicochemical data for Mudabbar and non mudabbar Kharekhasak (KK) powder have been set in.Diosgenin content was increased significantly in mudabbar KK. Abbreviations Used: KK: Kharekhasak, TT: Tribulus terrestris , MKK: mudabbar Kharekhasak, SK: Safoofe Kharekhasak , LOD: loss of weight on drying, HPTLC: High performance thin layer chromatography, BSS: British standard sieve, μl: microliter, SEM: Standard error of mean, nm: nanometer, g: gram.

Possible Mud Cracks Preserved in Martian Rock

NASA Image and Video Library

2017-01-17

The network of cracks in this Martian rock slab called "Old Soaker" may have formed from the drying of a mud layer more than 3 billion years ago. The view spans about 4 feet (1.2 meters) left-to-right and combines three images taken by the Mars Hand Lens Imager (MAHLI) camera on the arm of NASA's Curiosity Mars rover. Mud cracks would be evidence of a time when dry intervals interrupted wetter periods that supported lakes in the area. Curiosity has found evidence of ancient lakes in older, lower-lying rock layers and also in younger mudstone that is above Old Soaker. MAHLI was positioned about 3 feet (90 centimeters) above the surface when it took the component images on Dec. 31, 2016, during the 1,566th Martian day, or sol, of Curiosity's work on Mars. This observation was planned as part of assessing a hypothesis that the target preserves evidence of drying mud. The location is within an exposure of Murray formation mudstone on lower Mount Sharp inside Gale Crater. The slab bears a network of four- and five-sided polygons about half an inch to 1 inch (1 to 2 centimeters) across, which matches the pattern commonly formed when a thin layer of mud dries. Some edges of the polygons are ridges of material the same color as the surrounding rock. This could result from a three-step process after cracks form due to drying: Wind-blown sediments accumulate in the open cracks. Later, these sediments and the dried mud become rock under the pressure of multiple younger layers that accumulate on top of them. Most recently, after the overlying layers were eroded away by wind, the vein-filling material resists erosion better than the once-muddy material, so the pattern that began as cracks appears as ridges. Note that some of the cracks contain material much brighter than the surrounding rock. These are mineral veins. Curiosity has found such bright veins of calcium sulfate in many rock layers the rover has investigated. These veins form from circulation of mineral-laden groundwater through underground cracks. Rover-team scientists suggest that a likely scenario for the history of Old Soaker is more than one generation of fracturing: mud cracks first, with sediment accumulating in them, then a later episode of underground fracturing and vein forming. The target rock's name comes from the name of an island off the coast of Maine. The names informally assigned by the rover team to features in the area of lower Mount Sharp that includes this slab are from a list of islands, hills and other sites in or near Maine's Bar Harbor. http://photojournal.jpl.nasa.gov/catalog/PIA21261

Depositing bulk or micro-scale electrodes

DOEpatents

Shah, Kedar G.; Pannu, Satinderpall S.; Tolosa, Vanessa; Tooker, Angela C.; Sheth, Heeral J.; Felix, Sarah H.; Delima, Terri L.

2016-11-01

Thicker electrodes are provided on microelectronic device using thermo-compression bonding. A thin-film electrical conducting layer forms electrical conduits and bulk depositing provides an electrode layer on the thin-film electrical conducting layer. An insulating polymer layer encapsulates the electrically thin-film electrical conducting layer and the electrode layer. Some of the insulating layer is removed to expose the electrode layer.

All-nanoparticle self-assembly ZnO/TiO₂ heterojunction thin films with remarkably enhanced photoelectrochemical activity.

PubMed

Yuan, Sujun; Mu, Jiuke; Mao, Ruiyi; Li, Yaogang; Zhang, Qinghong; Wang, Hongzhi

2014-04-23

The multilaminated ZnO/TiO2 heterojunction films were successfully deposited on conductive substrates including fluorine-doped tin oxide (FTO) glass and flexible indium tin oxide coated poly(ethylene terephthalate) via the layer-by-layer (LBL) self assembly method from the oxide colloids without using any polyelectrolytes. The positively charged ZnO nanoparticles and the negatively charged TiO2 nanoparticles were directly used as the components in the consecutive deposition process to prepare the heterojunction thin films by varying the thicknesses. Moreover, the crystal growth of both oxides could be efficiently inhibited by the good connection between ZnO and TiO2 nanoparticles even after calcination at 500 °C, especially for ZnO which was able to keep the crystallite size under 25 nm. The as-prepared films were used as the working electrodes in the three-electrode photoelectrochemical cells. Because the well-contacted nanoscale heterojunctions were formed during the LBL self-assembling process, the ZnO/TiO2 all-nanoparticle films deposited on both substrates showed remarkably enhanced photoelectrochemical properties compared to that of the well-established TiO2 LBL thin films with similar thicknesses. The photocurrent response collected from the ZnO/TiO2 electrode on the FTO glass substrate was about five times higher than that collected from the TiO2 electrode. Owing to the absence of the insulating layer of dried polyelectrolytes, the ZnO/TiO2 all-nanoparticle heterojunction films were expected to be used in the photoelectrochemical device before calcination.

Method for bonding thin film thermocouples to ceramics

DOEpatents

Kreider, Kenneth G.

1993-01-01

A method is provided for adhering a thin film metal thermocouple to a ceramic substrate used in an environment up to 700 degrees Centigrade, such as at a cylinder of an internal combustion engine. The method includes the steps of: depositing a thin layer of a reactive metal on a clean ceramic substrate; and depositing thin layers of platinum and a platinum-10% rhodium alloy forming the respective legs of the thermocouple on the reactive metal layer. The reactive metal layer serves as a bond coat between the thin noble metal thermocouple layers and the ceramic substrate. The thin layers of noble metal are in the range of 1-4 micrometers thick. Preferably, the ceramic substrate is selected from the group consisting of alumina and partially stabilized zirconia. Preferably, the thin layer of reactive metal is in the range of 0.015-0.030 micrometers (15-30 nanometers) thick. The preferred reactive metal is chromium. Other reactive metals may be titanium or zirconium. The thin layer of reactive metal may be deposited by sputtering in ultra high purity argon in a vacuum of approximately 2 milliTorr (0.3 Pascals).

Multi-layer assemblies with predetermined stress profile and method for producing same

NASA Technical Reports Server (NTRS)

Heuer, Arthur H. (Inventor); Kahn, Harold (Inventor); Yang, Jie (Inventor); Phillips, Stephen M. (Inventor)

2003-01-01

Multi-layer assemblies of polysilicon thin films having predetermined stress characteristics and techniques for forming such assemblies are disclosed. In particular, a multi-layer assembly of polysilicon thin films may be produced that has a stress level of zero, or substantially so. The multi-layer assemblies comprise at least one constituent thin film having a tensile stress and at least one constituent thin film having a compressive stress. The thin films forming the multi-layer assemblies may be disposed immediately adjacent to one another without the use of intermediate layers between the thin films. Multi-layer assemblies exhibiting selectively determinable overall bending moments are also disclosed. Selective production of overall bending moments in microstructures enables manufacture of such structures with a wide array of geometrical configurations.

Cleaning of conveyor belt materials using ultrasound in a thin layer of water.

PubMed

Axelsson, L; Holck, A; Rud, I; Samah, D; Tierce, P; Favre, M; Kure, C F

2013-08-01

Cleaning of conveyor belts in the food industry is imperative for preventing the buildup of microorganisms that can contaminate food. New technologies for decreasing water and energy consumption of cleaning systems are desired. Ultrasound can be used for cleaning a wide range of materials. Most commonly, baths containing fairly large amounts of water are used. One possibility to reduce water consumption is to use ultrasonic cavitation in a thin water film on a flat surface, like a conveyor belt. In order to test this possibility, a model system was set up, consisting of an ultrasound transducer/probe with a 70-mm-diameter flat bottom, operating at 19.8 kHz, and contaminated conveyor belt materials in the form of coupons covered with a thin layer of water or water with detergent. Ultrasound was then applied on the water surface at different power levels (from 46 to 260 W), exposure times (10 and 20 s), and distances (2 to 20 mm). The model was used to test two different belt materials with various contamination types, such as biofilms formed by bacteria in carbohydrate- or protein-fat-based soils, dried microorganisms (bacteria, yeasts, and mold spores), and allergens. Ultrasound treatment increased the reduction of bacteria and yeast by 1 to 2 log CFU under the most favorable conditions compared with water or water-detergent controls. The effect was dependent on the type of belt material, the power applied, the exposure time, and the distance between the probe and the belt coupon. Generally, dried microorganisms were more easily removed than biofilms. The effect on mold spores was variable and appeared to be species and material dependent. Spiked allergens were also efficiently removed by using ultrasound. The results in this study pave the way for new cleaning designs for flat conveyor belts, with possibilities for savings of water, detergent, and energy consumption.

Optical Properties of Hybrid Inorganic/Organic Thin Film Encapsulation Layers for Flexible Top-Emission Organic Light-Emitting Diodes.

PubMed

An, Jae Seok; Jang, Ha Jun; Park, Cheol Young; Youn, Hongseok; Lee, Jong Ho; Heo, Gi-Seok; Choi, Bum Ho; Lee, Choong Hun

2015-10-01

Inorganic/organic hybrid thin film encapsulation layers consist of a thin Al2O3 layer together with polymer material. We have investigated optical properties of thin film encapsulation layers for top-emission flexible organic light-emitting diodes. The transmittance of hybrid thin film encapsulation layers and the electroluminescent spectrum of organic light-emitting diodes that were passivated by hybrid organic/inorganic thin film encapsulation layers were also examined as a function of the thickness of inorganic Al203 and monomer layers. The number of interference peaks, their intensity, and their positions in the visible range can be controlled by varying the thickness of inorganic Al2O3 layer. On the other hand, changing the thickness of monomer layer had a negligible effect on the optical properties. We also verified that there is a trade-off between transparency in the visible range and the permeation of water vapor in hybrid thin film encapsulation layers. As the number of dyads decreased, optical transparency improved while the water vapor permeation barrier was degraded. Our study suggests that, in top-emission organic light-emitting diodes, the thickness of each thin film encapsulation layer, in particular that of the inorganic layer, and the number of dyads should be controlled for highly efficient top-emission flexible organic light-emitting diodes.

Innovative manufacturing and materials for low cost lithium ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlson, Steven

2015-12-29

This project demonstrated entirely new manufacturing process options for lithium ion batteries with major potential for improved cost and performance. These new manufacturing approaches are based on the use of the new electrode-coated separators instead of the conventional electrode-coated metal current collector foils. The key enabler to making these electrode-coated separators is a new and unique all-ceramic separator with no conventional porous plastic separator present. A simple, low cost, and high speed manufacturing process of a single coating of a ceramic pigment and polymer binder onto a re-usable release film, followed by a subsequent delamination of the all-ceramic separator andmore » any layers coated over it, such as electrodes and metal current collectors, was utilized. A suitable all-ceramic separator was developed that demonstrated the following required features needed for making electrode-coated separators: (1) no pores greater than 100 nanometer (nm) in diameter to prevent any penetration of the electrode pigments into the separator; (2) no shrinkage of the separator when heated to the high oven heats needed for drying of the electrode layer; and (3) no significant compression of the separator layer by the high pressure calendering step needed to densify the electrodes by about 30%. In addition, this nanoporous all-ceramic separator can be very thin at 8 microns thick for increased energy density, while providing all of the performance features provided by the current ceramic-coated plastic separators used in vehicle batteries: improved safety, longer cycle life, and stability to operate at voltages up to 5.0 V in order to obtain even more energy density. The thin all-ceramic separator provides a cost savings of at least 50% for the separator component and by itself meets the overall goal of this project to reduce the cell inactive component cost by at least 20%. The all-ceramic separator also enables further cost savings by its excellent heat stability with no shrinkage at up to 220oC. This allows vacuum drying of the dry cell just before filling with the electrolyte and thereby can reduce the size of the cell assembly dry room by 50%. Once the electrode-coated separator is produced, there are many different approaches for adding the metal current collector layers and making and connecting the tabs of the cells. These approaches include: (1) laminating the electrode side of the electrode-coated separator to both sides of a metal current collector; and (2) making a full coated electrode stack by coating or depositing a current collector layer on the electrode side and then coating a second electrode layer onto the current collector. Further cost savings are available from using lower cost and/or thinner and lighter current collectors and from using a separator coating manufacturing process at widths of 1.5 meters (m) or more and at high production line speeds of up to 125 meters per minute (mpm), both of which are well above the conventional coating widths and line speeds presently used in manufacturing electrodes for lithium ion batteries.« less

A streptavidin linker layer that functions after drying.

PubMed

Xia, Nan; Shumaker-Parry, Jennifer S; Zareie, M Hadi; Campbell, Charles T; Castner, David G

2004-04-27

The ability of streptavidin (SA) to simultaneously bind four biotins is often used in linker layers, where a biotinylated molecule is linked to a biotin-functionalized surface via SA. For biosensor and array applications, it is desirable that the SA linker layer be stable to drying and rehydration. In this study it was observed that a significant decrease in binding capacity of a SA layer occurred when that layer was dried. For this study a SA linker layer was constructed by binding SA to a biotin-containing alkylthiolate monolayer (BAT/OEG) self-assembled onto gold. Its stability after drying was investigated using surface plasmon resonance (SPR). Approximately a quarter of the SA layer was removed from the BAT/OEG surface upon drying and rehydration, suggesting disruption of SA-biotin binding when dry. This resulted in the dried SA layer losing approximately 40% of its biotinylated ferritin (BF) binding capacity. Coating the layer with trehalose before drying was found to inhibit the loss of SA from the BAT/OEG surface. SPR showed that the trehalose-protected SA linker layer retained approximately 91% of its original BF binding capacity after drying and rehydration. Atomic force microscopy, which was used to image individual surface-bound SA and BF molecules, qualitatively confirmed these observations.

Composite polymeric film and method for its use in installing a very-thin polymeric film in a device

DOEpatents

Duchane, D.V.; Barthell, B.L.

1982-04-26

A composite polymeric film and a method for its use in forming and installing a very thin (< 10 ..mu..m) polymeric film are disclosed. The composite film consists of a thin film layer and a backing layer. The backing layer is soluble in a solvent in which the thin film layer is not soluble. In accordance with the method, the composite film is installed in a device in the same position in which it is sought to finally emplace the thin film. The backing layer is then selectiely dissolved in the solvent to leave the insoluble thin film layer as an unbacked film. The method permits a very thin film to e successfully installed in devices where the fragility of the film would preclude handling and installation by conventional methods.

Composite polymeric film and method for its use in installing a very thin polymeric film in a device

DOEpatents

Duchane, David V.; Barthell, Barry L.

1984-01-01

A composite polymeric film and a method for its use in forming and installing a very thin (<10 .mu.m) polymeric film are disclosed. The composite film consists of a thin film layer and a backing layer. The backing layer is soluble in a solvent in which the thin film layer is not soluble. In accordance with the method, the composite film is installed in a device in the same position in which it is sought to finally emplace the thin film. The backing layer is then selectively dissolved in the solvent to leave the insoluble thin film layer as an unbacked film. The method permits a very thin film to be successfully installed in devices where the fragility of the film would preclude handling and installation by conventional methods.

Responses to the 2800 years BP climatic oscillation in shallow- and deep-basin sediments from the Dead Sea

NASA Astrophysics Data System (ADS)

Neugebauer, Ina; Brauer, Achim; Schwab, Markus; Dulski, Peter; Frank, Ute; Hadzhiivanova, Elitsa; Kitagawa, Hiroyuki; Litt, Thomas; Schiebel, Vera; Taha, Nimer; Waldmann, Nicolas

2015-04-01

Laminated lake sediments from the Dead Sea basin provide high-resolution records of climatic variability in the eastern Mediterranean region, which is considered being especially sensitive to changing climatic conditions. In the study presented here, we aim to reconstruct palaeoclimatic changes and their relation to the frequency of flood/erosion and dust deposition events as archived in the Dead Sea basin for the time interval from ca 3700 to 1700 years BP. A ca 4 m thick, mostly annually laminated (varved) sediment section from the western margin of the Dead Sea (shallow-water DSEn - Ein Gedi profile) was analysed and correlated to the new ICDP Dead Sea Deep Drilling Project core 5017-1 from the deep basin. To detect even single event layers, we applied a multi-proxy approach of high-resolution microscopic thin section analyses, µXRF element scanning and magnetic susceptibility measurements, supported by grain size and palynological analyses. Based on radiocarbon and varve dating two pronounced dry periods were detected at ~3500-3300 yrs BP and ~2900-2400 yrs BP that are characterized by a sand deposit during the older dry period and enhanced frequency of coarse detrital layers during the younger dry period in the shallow-water DSEn core, both interpreted as increased erosion processes. In the 5017-1 deep-basin core these dry periods are depicted by halite deposits. The timing of the younger dry period broadly coincides with the Homeric Minimum of solar activity at ca 2800 yrs BP. Our results suggest that during this period the Dead Sea region experienced a change in synoptic weather patterns leading to an increased occurrence of flash-flood events, overprinting the overall dry climatic conditions. Following this dry spell, a 250-yrs period of increased dust deposition is observed, coinciding with more regular aragonite precipitation during less arid climatic conditions.

Determination of drying kinetics and convective heat transfer coefficients of ginger slices

NASA Astrophysics Data System (ADS)

Akpinar, Ebru Kavak; Toraman, Seda

2016-10-01

In the present work, the effects of some parametric values on convective heat transfer coefficients and the thin layer drying process of ginger slices were investigated. Drying was done in the laboratory by using cyclone type convective dryer. The drying air temperature was varied as 40, 50, 60 and 70 °C and the air velocity is 0.8, 1.5 and 3 m/s. All drying experiments had only falling rate period. The drying data were fitted to the twelve mathematical models and performance of these models was investigated by comparing the determination of coefficient ( R 2), reduced Chi-square ( χ 2) and root mean square error between the observed and predicted moisture ratios. The effective moisture diffusivity and activation energy were calculated using an infinite series solution of Fick's diffusion equation. The average effective moisture diffusivity values and activation energy values varied from 2.807 × 10-10 to 6.977 × 10-10 m2/s and 19.313-22.722 kJ/mol over the drying air temperature and velocity range, respectively. Experimental data was used to evaluate the values of constants in Nusselt number expression by using linear regression analysis and consequently, convective heat transfer coefficients were determined in forced convection mode. Convective heat transfer coefficient of ginger slices showed changes in ranges 0.33-2.11 W/m2 °C.

Capillary-Driven Microfluidic Chips for Miniaturized Immunoassays: Patterning Capture Antibodies Using Microcontact Printing and Dry-Film Resists.

PubMed

Temiz, Yuksel; Lovchik, Robert D; Delamarche, Emmanuel

2017-01-01

The miniaturization of immunoassays using microfluidic devices is attractive for many applications, but an important challenge remains the patterning of capture antibodies (cAbs) on the surface of microfluidic structures. Here, we describe how to pattern cAbs on planar poly(dimethylsiloxane) (PDMS) stamps and how to microcontact print the cAbs on a dry-film resist (DFR). DFRs are new types of photoresists having excellent chemical resistance and good mechanical, adhesive, and optical properties. Instead of being liquid photoresists, DFRs are thin layers that are easy to handle, cut, photo-pattern, and laminate over surfaces. We show how to perform a simple fluorescence immunoassay using anti-biotin cAbs patterned on a 50-μm-thick DF-1050 DFR, Atto 647N-biotin analytes, and capillary-driven chips fabricated in silicon.

Development towards Compact Nitrocellulose-Based Interferometric Biochips for Dry Eye MMP9 Label-Free In-Situ Diagnosis

PubMed Central

Santamaría, Beatriz; Laguna, María F.; López-Romero, David; Hernandez, Ana L.; Sanza, Francisco J.; Lavín, Álvaro; Casquel, Rafael; Maigler, María V.; Espinosa, Rocío L.; Holgado, Miguel

2017-01-01

A novel compact optical biochip based on a thin layer-sensing surface of nitrocellulose is used for in-situ label-free detection of metalloproteinase (MMP9) related to dry eye disease. In this article, a new integrated chip with different interferometric transducers layout with an optimal sensing surface is reported for the first time. We demonstrate that specific antibodies can be immobilized onto these transducers with a very low volume of sample and with good orientation. Many sensing transducers constitute the presented biochip in order to yield statistical data and stability in the acquired measurements. As a result, we report the recognition curve for pure recombinant MMP9, tests of model tears with MMP9, and real tear performance from patients, with a promising limit of detection. PMID:28534808

Impact of saccharides on the drying kinetics of agarose gels measured by in-situ interferometry

NASA Astrophysics Data System (ADS)

Mao, Bosi; Divoux, Thibaut; Snabre, Patrick

2017-01-01

Agarose gels are viscoelastic soft solids that display a porous microstructure filled with water at 90% w/w or more. Despite an extensive use in food industry and microbiology, little is known about the drying kinetics of such squishy solids, which suffers from a lack of time-resolved local measurements. Moreover, only scattered empirical observations are available on the role of the gel composition on the drying kinetics. Here we study by in-situ interferometry the drying of agarose gels of various compositions cast in Petri dishes. The gel thinning is associated with the displacement of interference fringes that are analyzed using an efficient spatiotemporal filtering method, which allows us to assess local thinning rates as low as 10 nm/s with high accuracy. The gel thinning rate measured at the center of the dish appears as a robust observable to quantify the role of additives on the gel drying kinetics and compare the drying speed of agarose gels loaded with various non-gelling saccharides of increasing molecular weights. Our work shows that saccharides systematically decrease the agarose gel thinning rate up to a factor two, and exemplifies interferometry as a powerful tool to quantify the impact of additives on the drying kinetics of polymer gels.

Plant-derived cis-β-ocimene as a precursor for biocompatible, transparent, thermally-stable dielectric and encapsulating layers for organic electronics.

PubMed

Bazaka, Kateryna; Destefani, Ryan; Jacob, Mohan V

2016-12-09

This article presents low-temperature, one-step dry synthesis of optically transparent thermally-stable, biocompatible cis-β-ocimene-based thin films for applications as interlayer dielectric and encapsulating layer for flexible electronic devices, e.g. OLEDs. Morphological analysis of thin films shows uniform, very smooth (R q  < 1 nm) and defect-free moderately hydrophilic surfaces. The films are optically transparent, with a refractive index of ~1.58 at 600 nm, an optical band gap of ~2.85 eV, and dielectric constant of 3.5-3.6 at 1 kHz. Upon heating, thin films are chemically and optically stable up to at least 200 °C, where thermal stability increases for films manufactured at higher RF power as well as for films deposited away from the plasma glow. Heating of the sample increases the dielectric constant, from 3.7 (25 °C) to 4.7 (120 °C) at 1 kHz for polymer fabricated at 25 W. Polymers are biocompatible with non-adherent THP-1 cells and adherent mouse macrophage cells, including LPS-stimulated macrophages, and maintain their material properties after 48 h of immersion into simulated body fluid. The versatile nature of the films fabricated in this study may be exploited in next-generation consumer electronics and energy technologies.

Plant-derived cis-β-ocimene as a precursor for biocompatible, transparent, thermally-stable dielectric and encapsulating layers for organic electronics

PubMed Central

Bazaka, Kateryna; Destefani, Ryan; Jacob, Mohan V.

2016-01-01

This article presents low-temperature, one-step dry synthesis of optically transparent thermally-stable, biocompatible cis−β−ocimene-based thin films for applications as interlayer dielectric and encapsulating layer for flexible electronic devices, e.g. OLEDs. Morphological analysis of thin films shows uniform, very smooth (Rq < 1 nm) and defect-free moderately hydrophilic surfaces. The films are optically transparent, with a refractive index of ~1.58 at 600 nm, an optical band gap of ~2.85 eV, and dielectric constant of 3.5−3.6 at 1 kHz. Upon heating, thin films are chemically and optically stable up to at least 200 °C, where thermal stability increases for films manufactured at higher RF power as well as for films deposited away from the plasma glow. Heating of the sample increases the dielectric constant, from 3.7 (25 °C) to 4.7 (120 °C) at 1 kHz for polymer fabricated at 25 W. Polymers are biocompatible with non-adherent THP–1 cells and adherent mouse macrophage cells, including LPS-stimulated macrophages, and maintain their material properties after 48 h of immersion into simulated body fluid. The versatile nature of the films fabricated in this study may be exploited in next-generation consumer electronics and energy technologies. PMID:27934916

Plant-derived cis-β-ocimene as a precursor for biocompatible, transparent, thermally-stable dielectric and encapsulating layers for organic electronics

NASA Astrophysics Data System (ADS)

Bazaka, Kateryna; Destefani, Ryan; Jacob, Mohan V.

2016-12-01

This article presents low-temperature, one-step dry synthesis of optically transparent thermally-stable, biocompatible cis-β-ocimene-based thin films for applications as interlayer dielectric and encapsulating layer for flexible electronic devices, e.g. OLEDs. Morphological analysis of thin films shows uniform, very smooth (Rq < 1 nm) and defect-free moderately hydrophilic surfaces. The films are optically transparent, with a refractive index of ~1.58 at 600 nm, an optical band gap of ~2.85 eV, and dielectric constant of 3.5-3.6 at 1 kHz. Upon heating, thin films are chemically and optically stable up to at least 200 °C, where thermal stability increases for films manufactured at higher RF power as well as for films deposited away from the plasma glow. Heating of the sample increases the dielectric constant, from 3.7 (25 °C) to 4.7 (120 °C) at 1 kHz for polymer fabricated at 25 W. Polymers are biocompatible with non-adherent THP-1 cells and adherent mouse macrophage cells, including LPS-stimulated macrophages, and maintain their material properties after 48 h of immersion into simulated body fluid. The versatile nature of the films fabricated in this study may be exploited in next-generation consumer electronics and energy technologies.

Multi-layered, chemically bonded lithium-ion and lithium/air batteries

DOEpatents

Narula, Chaitanya Kumar; Nanda, Jagjit; Bischoff, Brian L; Bhave, Ramesh R

2014-05-13

Disclosed are multilayer, porous, thin-layered lithium-ion batteries that include an inorganic separator as a thin layer that is chemically bonded to surfaces of positive and negative electrode layers. Thus, in such disclosed lithium-ion batteries, the electrodes and separator are made to form non-discrete (i.e., integral) thin layers. Also disclosed are methods of fabricating integrally connected, thin, multilayer lithium batteries including lithium-ion and lithium/air batteries.

Open sun drying of green bean: influence of pretreatments on drying kinetics, colour and rehydration capacity

NASA Astrophysics Data System (ADS)

İsmail, Osman; Kantürk Figen, Aysel; Pişkin, Sabriye

2017-04-01

Green bean ( Phaseolus Vulgaris L), classified under legume family, is a primary source of dietary protein in human diets especially in the agricultural countries. Green bean is susceptible to rapid deterioration because of their high moisture content and in order to prevent and present the green bean drying process is applied. In this study, effects of pretreatments on drying kinetics, colour and rehydration capacity of green bean were investigated. It was observed that the pretreatment affected the drying time. The shortest drying times were obtained from pretreated samples with blanched. Drying times were determined as 47, 41 and 29 h for natural, salted and blanch, respectively. The results showed that pretreatment and ambient temperature significantly ( P = 0.05) affected the drying rate and the drying time. The effective moisture diffusivity was determined by using Fick's second law and was found to be range between 3.15 × 10-10 and 1.2 × 10-10 m2/s for the pre-treated and natural green bean samples. The rehydration values were obtained 2.75, 2.71, 2.29 (g water/g dry matter) for the blanched, salted and natural samples. The effective diffusion coefficients were calculated using the data collected during the falling rate period and the experimental data are fitted to seven thin layer drying models which found in the literature. The Logarithmic model was found to best describe the drying behavior of fresh green beans under open air sun. Rehydration time and color parameters had been determined in order to improve the quality of dried green bean. Regarding with rehydration time and colour data, the best results were obtained at blanched drying conditions.

Fluorine incorporation in solution-processed poly-siloxane passivation for highly reliable a-InGaZnO thin-film transistors

NASA Astrophysics Data System (ADS)

Yoshida, Naofumi; Bermundo, Juan Paolo; Ishikawa, Yasuaki; Nonaka, Toshiaki; Taniguchi, Katsuto; Uraoka, Yukiharu

2018-03-01

We investigated a fluorine-containing polysiloxane (Poly-SX) passivation layer fabricated by solution process for amorphous InGaZnO (a-IGZO) thin-film transistors (TFT). This passivation layer greatly improved the stability of the a-IGZO device even after being subjected to positive bias stress (PBS) and negative bias stress (NBS). The mobility (µ) of TFTs passivated by fluorine-containing Poly-SX increased by 31%-56% (10.50-12.54 cm2 V-1 s-1) compared with TFTs passivated by non-fluorinated Poly-SX (8.04 cm2 V-1 s-1). Increasing the amount of fluorine additives led to a higher µ in passivated TFTs. Aside from enhancing the performance, these passivation layers could increase the reliability of a-IGZO TFTs under PBS and NBS with a minimal threshold voltage shift (ΔV th) of up to  +0.2 V and  -0.1 V, respectively. Additionally, all TFTs passivated by the fluorinated passivation materials did not exhibit a hump effect after NBS. We also showed that fluorinated photosensitive Poly-SX, which can be fabricated without any dry etching process, had an effective passivation property. In this report, we demonstrated the photolithography of Poly-SX, and electrical properties of Poly-SX passivated TFTs, and analyzed the state of the a-IGZO layer to show the large potential of Poly-SX as an effective solution-processed passivation material.

Fabrication of low-temperature solid oxide fuel cells with a nanothin protective layer by atomic layer deposition

PubMed Central

2013-01-01

Anode aluminum oxide-supported thin-film fuel cells having a sub-500-nm-thick bilayered electrolyte comprising a gadolinium-doped ceria (GDC) layer and an yttria-stabilized zirconia (YSZ) layer were fabricated and electrochemically characterized in order to investigate the effect of the YSZ protective layer. The highly dense and thin YSZ layer acted as a blockage against electron and oxygen permeation between the anode and GDC electrolyte. Dense GDC and YSZ thin films were fabricated using radio frequency sputtering and atomic layer deposition techniques, respectively. The resulting bilayered thin-film fuel cell generated a significantly higher open circuit voltage of approximately 1.07 V compared with a thin-film fuel cell with a single-layered GDC electrolyte (approximately 0.3 V). PMID:23342963

Thin film electronic devices with conductive and transparent gas and moisture permeation barriers

DOEpatents

Simpson, Lin Jay

2015-07-28

Thin film electronic devices (or stacks integrated with a substrate) that include a permeation barrier formed of a thin layer of metal that provides a light transmitting and electrically conductive layer, wherein the electrical conductive layer is formed on a surface of the substrate or device layer such as a transparent conducting material layer with pin holes or defects caused by manufacturing and the thin layer of metal is deposited on the conductive layer and formed from a self-healing metal that forms self-terminating oxides. A permeation plug or block is formed in or adjacent to the thin film of metal at or proximate to the pin holes to block further permeation of contaminants through the pin holes.

Large area polysilicon films with predetermined stress characteristics and method for producing same

NASA Technical Reports Server (NTRS)

Heuer, Arthur H. (Inventor); Kahn, Harold (Inventor); Yang, Jie (Inventor); Phillips, Stephen M. (Inventor)

2002-01-01

Multi-layer assemblies of polysilicon thin films having predetermined stress characteristics and techniques for forming such assemblies are disclosed. In particular, a multi-layer assembly of polysilicon thin films may be produced that has a stress level of zero, or substantially so. The multi-layer assemblies comprise at least one constituent thin film having a tensile stress and at least one constituent thin film having a compressive stress. The thin films forming the multi-layer assemblies may be disposed immediately adjacent to one another without the use of intermediate layers between the thin films. Multi-layer assemblies exhibiting selectively determinable overall bending moments are also disclosed. Selective production of overall bending moments in microstructures enables manufacture of such structures with a wide array of geometrical configurations.

Controlled Deposition and Performance Optimization of Perovskite Solar Cells Using Ultrasonic Spray-Coating of Photoactive Layers.

PubMed

Chang, Wei-Chieh; Lan, Ding-Hung; Lee, Kun-Mu; Wang, Xiao-Feng; Liu, Cheng-Liang

2017-04-10

This study investigated a new film-deposition technique, ultrasonic spray-coating, for use in the production of a photoactive layer of perovskite solar cells. Stable atomization and facile fabrication of perovskite thin films by ultrasonic spray-coating were achieved in a one-step method through manipulating the ink formulation (e.g., solution concentration, precursor composition, and mixing solvent ratio) and the drying kinetics (e.g., post-annealing temperature). The performance of the perovskite solar cells was mainly influenced by the intrinsic film morphology and crystalline orientation of the deposited perovskite layer. By suitable optimization of the spreading and drying conditions of the ink, ultrasonic spray-coated perovskite photovoltaic devices were obtained with a maximum power conversion efficiency of 11.30 %, a fill factor of 73.6 %, a short-circuit current of 19.7 mA cm -1 , and an open-circuit voltage of 0.78 V, respectively. Notably, the average power efficiency reached above 10 %, attributed to the large flower-like perovskite crystal with orientation along the (1 1 2)/(2 0 0) and (2 2 4)/(4 0 0) directions. Thus, the ultrasonic spray-coating method for perovskite photoactive layers, combining advantages of good photovoltaic performance results and benefits from cost and processing, has the potential for large-scale commercial production. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison Between Navier-Stokes and Thin-Layer Computations for Separated Supersonic Flow

NASA Technical Reports Server (NTRS)

Degani, David; Steger, Joseph L.

1983-01-01

In the numerical simulation of high Reynolds-number flow, one can frequently supply only enough grid points to resolve the viscous terms in a thin layer. As a consequence, a body-or stream-aligned coordinate system is frequently used and viscous terms in this direction are discarded. It is argued that these terms cannot be resolved and computational efficiency is gained by their neglect. Dropping the streamwise viscous terms in this manner has been termed the thin-layer approximation. The thin-layer concept is an old one, and similar viscous terms are dropped, for example, in parabolized Navier-Stokes schemes. However, such schemes also make additional assumptions so that the equations can be marched in space, and such a restriction is not usually imposed on a thin-layer model. The thin-layer approximation can be justified in much the same way as the boundary-layer approximation; it requires, therefore, a body-or stream-aligned coordinate and a high Reynolds number. Unlike the boundary-layer approximation, the same equations are used throughout, so there is no matching problem. Furthermore, the normal momentum equation is not simplified and the convection terms are not one-sided differenced for marching. Consequently, the thin-layer equations are numerically well behaved at separation and require no special treatment there. Nevertheless, the thin-layer approximation receives criticism. It has been suggested that the approximation is invalid at separation and, more recently, that it is inadequate for unsteady transonic flow. Although previous comparisons between the thin-layer and Navier-Stokes equations have been made, these comparisons have not been adequately documented.

Triacetin as food additive in gummy candy and other foodstuffs on the market.

PubMed

Ogawa, T; Moriwaki, N; Fujii, R; Tanaka, K; Mori, E; Saitou, M; Yoshizawa, H; Sakaguchi, H

1992-04-01

The qualitative and quantitative analytical methods were proposed for the simple and rapid determination of triacetin (TAc) in commercial gummy candies and other foodstuffs by gas chromatography (GC), thin layer chromatography (TLC) and infrared spectroscopy (IR). Each extract from the samples was obtained by pretreatment of the foodstuffs as follows: (A) Gummy candy was dissolved in warm water and the solution was extracted with chloroform. The organic (chloroform) layer was separated. (B) Samples (such as ice cream) containing substantial water were mixed with anhydrous Na2SO4 and stirred to sandy appearance and dried. The residue was homogenized with ether, followed by centrifuging, and the organic (ether) layer was separated. (C) Dried samples (such as chocolate and cookie) were smashed, homogenized with ether, and followed by centrifuging, and the organic (ether) layer was separated. (D) Candy was dissolved in warm water and the solution was extracted with ether. The organic (ether) layer was separated. Each organic layer from (A)-(D) was washed with 10% NaHCO3 and evaporated. The residue containing TAc was dissolved in dichloromethane. The extract obtained was subjected to column chromatography on silica gel. The fractions containing TAc were employed in GC with 25% PEG-20M column, TLC, and IR analyses. Recovery of TAc from gummy candy was 99.1 +/- 3.0% and those from other foodstuffs ranged from was 82.1 to 99.4% by GC. Detection limit by this method was 10 ppm. TAc was found to contain at a level as high as 550 ppm in one domestic gummy candy. On the other hand, one imported gummy candy contained no more than 20 ppm of TAc gummy candy.

Multilayer composites and manufacture of same

DOEpatents

Holesinger, Terry G.; Jia, Quanxi

2006-02-07

The present invention is directed towards a process of depositing multilayer thin films, disk-shaped targets for deposition of multilayer thin films by a pulsed laser or pulsed electron beam deposition process, where the disk-shaped targets include at least two segments with differing compositions, and a multilayer thin film structure having alternating layers of a first composition and a second composition, a pair of the alternating layers defining a bi-layer wherein the thin film structure includes at least 20 bi-layers per micron of thin film such that an individual bi-layer has a thickness of less than about 100 nanometers.

Current-voltage characteristics and electroresistance in LaMnO3-δ/La0.7Ca0.3MnO3/LaAlO3 thin film composites.

PubMed

Gadani, Keval; Keshvani, M J; Rajyaguru, Bhargav; Dhruv, Davit; Kataria, B R; Joshi, A D; Asokan, K; Shah, N A; Solanki, P S

2017-11-08

In this communication, we report results of the electrical transport properties across the interface of composites consisting of n-type LaMnO 3-δ (LMO) and p-type La 0.7 Ca 0.3 MnO 3 (LCMO) manganites grown on LaAlO 3 (LAO) single crystalline substrates using low cost wet chemical solution deposition (CSD) and sophisticated, well-controlled dry chemical vapor deposition (CVD) chemical techniques. The XRD ϕ-scan studies reveal the single crystalline nature of both bilayered composites, with parallel epitaxial growth of LMO and LCMO layers onto the LAO substrate. The valence states of Mn ions in both layers of both composites were identified by performing X-ray photoelectron spectroscopy (XPS). The I-V characteristics of the LMO/LCMO interfaces show strong backward diode-like behavior at higher applied voltages well above the crossover voltage (V NB ). Below V NB , the interfaces demonstrate normal diode-like characteristics throughout the studied temperature range. The electric field-induced modulation of the LMO/LCMO junction resistance of the interfaces has been observed. Electric field-dependent electroresistance (ER) modifications at different temperatures have also been studied. The electrical transport properties have been discussed in the context of various mechanisms, such as charge injection, tunneling, depletion region modification and thermal processes across the interface. The effects of structurally and chemically developed sharp interfaces between the LMO and LCMO layers on the transport properties of the presently studied bilayered thin film composites have been discussed on the basis of correlation between the physicochemical characterization and charge transport behavior. A comparison of different aspects of the transport properties has been presented in the context of the structural strain and crystallinity of the composites grown using both wet and dry chemical techniques.

Combinatorial screening of halide perovskite thin films and solar cells by mask-defined IR laser molecular beam epitaxy

PubMed Central

Kawashima, Kazuhiro; Okamoto, Yuji; Annayev, Orazmuhammet; Toyokura, Nobuo; Takahashi, Ryota; Lippmaa, Mikk; Itaka, Kenji; Suzuki, Yoshikazu; Matsuki, Nobuyuki; Koinuma, Hideomi

2017-01-01

Abstract As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic–inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH3NH3I) and inorganic halide (B-site: PbI2) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I-V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI2 and CH3NH3I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell. PMID:28567176

Fuel treatment effects on tree mortality following wildfire in dry mixed conifer forests, Washington State, USA

Treesearch

Susan J. Prichard; Maureen C. Kennedy

2012-01-01

Fuel reduction treatments are increasingly used to mitigate future wildfire severity in dry forests, but few opportunities exist to assess their effectiveness. We evaluated the influence of fuel treatment, tree size and species on tree mortality following a large wildfire event in recent thin-only, thin and prescribed burn (thin-Rx) units. Of the trees that died within...

Vacuum drying of apples (cv. Golden Delicious): drying characteristics, thermodynamic properties, and mass transfer parameters

NASA Astrophysics Data System (ADS)

Nadi, Fatemeh; Tzempelikos, Dimitrios

2018-01-01

In this work, apples of cv. Golden Delicious were cut into slices that were 5 and 7 mm thick and then vacuum dried at 50, 60 and 70 °C and pressure of 0.02 bar. The thin layer model drying kinetics was studied, and mass transfer properties, specifically effective moisture diffusivity and convective mass transfer coefficient, were evaluated using the Fick's equation of diffusion. Also, thermodynamic parameters of the process, i.e. enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG), were determined. Colour properties were evaluated as one of the important indicators of food quality and marketability. Determination of mass transfer parameters and thermodynamic properties of vacuum dried apple slices has not been discussed much in the literature. In conclusion, the Nadi's model fitted best the observed data that represent the drying process. Thermodynamic properties were determined based on the dependence of the drying constant of the Henderson and Pabis model on temperature, and it was concluded that the variation in drying kinetics depends on the energy contribution of the surrounding environment. The enthalpy and entropy diminished, while the Gibbs free energy increased with the increase of the temperature of drying; therefore, it was possible to verify that variation in the diffusion process in the apple during drying depends on energetic contributions of the environment. The obtained results showed that diffusivity increased for 69%, while the mass transfer coefficient increase was even higher, 75%, at the variation of temperature of 20 °C. The increase in the dimensionless Biot number was 20%.

Vacuum drying of apples (cv. Golden Delicious): drying characteristics, thermodynamic properties, and mass transfer parameters

NASA Astrophysics Data System (ADS)

Nadi, Fatemeh; Tzempelikos, Dimitrios

2018-07-01

In this work, apples of cv. Golden Delicious were cut into slices that were 5 and 7 mm thick and then vacuum dried at 50, 60 and 70 °C and pressure of 0.02 bar. The thin layer model drying kinetics was studied, and mass transfer properties, specifically effective moisture diffusivity and convective mass transfer coefficient, were evaluated using the Fick's equation of diffusion. Also, thermodynamic parameters of the process, i.e. enthalpy ( ΔH), entropy ( ΔS) and Gibbs free energy ( ΔG), were determined. Colour properties were evaluated as one of the important indicators of food quality and marketability. Determination of mass transfer parameters and thermodynamic properties of vacuum dried apple slices has not been discussed much in the literature. In conclusion, the Nadi's model fitted best the observed data that represent the drying process. Thermodynamic properties were determined based on the dependence of the drying constant of the Henderson and Pabis model on temperature, and it was concluded that the variation in drying kinetics depends on the energy contribution of the surrounding environment. The enthalpy and entropy diminished, while the Gibbs free energy increased with the increase of the temperature of drying; therefore, it was possible to verify that variation in the diffusion process in the apple during drying depends on energetic contributions of the environment. The obtained results showed that diffusivity increased for 69%, while the mass transfer coefficient increase was even higher, 75%, at the variation of temperature of 20 °C. The increase in the dimensionless Biot number was 20%.

Thin Film Coating with Highly Dispersible Barium Titanate-Polyvinylpyrrolidone Nanoparticles.

PubMed

Li, Jinhui; Inukai, Koji; Takahashi, Yosuke; Tsuruta, Akihiro; Shin, Woosuck

2018-05-01

Thin BaTiO₃ (BT) coating layers are required in various multilayer ceramic technologies, and fine nanosized BT particles with good dispersion in solution are essential for this coating process. In this work, cubic and tetragonal phase monodispersed BT nanoparticles—which were referred to as LBT and HBT-PVP coated on their surface by polyvinylpyrrolidone (PVP) polymer—were prepared by low temperature synthesis (LTS) and hydrothermal method (HT) at 80 and 230 °C, respectively. They were applied for the thin film coating on polyethylene terephthalate (PET) and Si wafer substrates by a simple bar coating. The thickness of BT, LBT-PVP, and HBT-PVP films prepared by their 5 wt % coating agent on Si are around 268, 308, and 263 nm, and their surface roughness are 104.6, 91.6, and 56.1 nm, respectively. The optical transmittance of BT, LBT-PVP, and HBT-PVP films on PET are 55, 66, and 73% at 550 nm wavelength and the haze values are 34.89, 24.70, and 20.53% respectively. The mechanism of dispersant adsorbed on the BT surface for densification of thin film during the drying process of the film was discussed.

Thin Film Coating with Highly Dispersible Barium Titanate-Polyvinylpyrrolidone Nanoparticles

PubMed Central

Li, Jinhui; Inukai, Koji; Takahashi, Yosuke; Tsuruta, Akihiro; Shin, Woosuck

2018-01-01

Thin BaTiO3 (BT) coating layers are required in various multilayer ceramic technologies, and fine nanosized BT particles with good dispersion in solution are essential for this coating process. In this work, cubic and tetragonal phase monodispersed BT nanoparticles—which were referred to as LBT and HBT-PVP coated on their surface by polyvinylpyrrolidone (PVP) polymer—were prepared by low temperature synthesis (LTS) and hydrothermal method (HT) at 80 and 230 °C, respectively. They were applied for the thin film coating on polyethylene terephthalate (PET) and Si wafer substrates by a simple bar coating. The thickness of BT, LBT-PVP, and HBT-PVP films prepared by their 5 wt % coating agent on Si are around 268, 308, and 263 nm, and their surface roughness are 104.6, 91.6, and 56.1 nm, respectively. The optical transmittance of BT, LBT-PVP, and HBT-PVP films on PET are 55, 66, and 73% at 550 nm wavelength and the haze values are 34.89, 24.70, and 20.53% respectively. The mechanism of dispersant adsorbed on the BT surface for densification of thin film during the drying process of the film was discussed. PMID:29724007

Ordered organic-organic multilayer growth

DOEpatents

Forrest, Stephen R.; Lunt, Richard R.

2016-04-05

An ordered multilayer crystalline organic thin film structure is formed by depositing at least two layers of thin film crystalline organic materials successively wherein the at least two thin film layers are selected to have their surface energies within .+-.50% of each other, and preferably within .+-.15% of each other, whereby every thin film layer within the multilayer crystalline organic thin film structure exhibit a quasi-epitaxial relationship with the adjacent crystalline organic thin film.

Ordered organic-organic multilayer growth

DOEpatents

Forrest, Stephen R; Lunt, Richard R

2015-01-13

An ordered multilayer crystalline organic thin film structure is formed by depositing at least two layers of thin film crystalline organic materials successively wherein the at least two thin film layers are selected to have their surface energies within .+-.50% of each other, and preferably within .+-.15% of each other, whereby every thin film layer within the multilayer crystalline organic thin film structure exhibit a quasi-epitaxial relationship with the adjacent crystalline organic thin film.

Nano-crystalline thin and nano-particulate thick TiO{sub 2} layer: Cost effective sequential deposition and study on dye sensitized solar cell characteristics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, P.; Sengupta, D.; CSIR-Central Mechanical Engineering Research Institute, Academy of Scientific and Innovative Research

Highlights: • Thin TiO{sub 2} layer is deposited on conducting substrate using sol–gel based dip coating. • TiO{sub 2} nano-particles are synthesized using hydrothermal route. • Thick TiO{sub 2} particulate layer is deposited on prepared thin layer. • Dye sensitized solar cells are made using thin and thick layer based photo-anode. • Introduction of thin layer in particulate photo-anode improves the cell efficiency. - Abstract: A compact thin TiO{sub 2} passivation layer is introduced between the mesoporous TiO{sub 2} nano-particulate layer and the conducting glass substrate to prepare photo-anode for dye-sensitized solar cell (DSSC). In order to understand the effectmore » of passivation layer, other two DSSCs are also developed separately using TiO{sub 2} nano-particulate and compact thin film based photo-anodes. Nano-particles are prepared using hydrothermal synthesis route and the compact passivation layer is prepared by simply dip coating the precursor sol prepared through wet chemical route. The TiO{sub 2} compact layer and the nano-particles are characterised in terms of their micro-structural features and phase formation behavior. It is found that introduction of a compact TiO{sub 2} layer in between the mesoporous TiO{sub 2} nano-particulate layer and the conducting substrate improves the solar to electric conversion efficiency of the fabricated cell. The dense thin passivation layer is supposed to enhance the photo-excited electron transfer and prevent the recombination of photo-excited electrons.« less

Isotropic plasma etching of Ge Si and SiN x films

DOE PAGES

Henry, Michael David; Douglas, Erica Ann

2016-08-31

This study reports on selective isotropic dry etching of chemically vapor deposited (CVD) Ge thin film, release layers using a Shibaura chemical downstream etcher (CDE) with NF 3 and Ar based plasma chemistry. Relative etch rates between Ge, Si and SiN x are described with etch rate reductions achieved by adjusting plasma chemistry with O 2. Formation of oxides reducing etch rates were measured for both Ge and Si, but nitrides or oxy-nitrides created using direct injection of NO into the process chamber were measured to increase Si and SiN x etch rates while retarding Ge etching.

Transparent and flexible high-performance supercapacitors based on single-walled carbon nanotube films

NASA Astrophysics Data System (ADS)

Kanninen, Petri; Dang Luong, Nguyen; Hoang Sinh, Le; Anoshkin, Ilya V.; Tsapenko, Alexey; Seppälä, Jukka; Nasibulin, Albert G.; Kallio, Tanja

2016-06-01

Transparent and flexible energy storage devices have garnered great interest due to their suitability for display, sensor and photovoltaic applications. In this paper, we report the application of aerosol synthesized and dry deposited single-walled carbon nanotube (SWCNT) thin films as electrodes for an electrochemical double-layer capacitor (EDLC). SWCNT films exhibit extremely large specific capacitance (178 F g-1 or 552 μF cm-2), high optical transparency (92%) and stability for 10 000 charge/discharge cycles. A transparent and flexible EDLC prototype is constructed with a polyethylene casing and a gel electrolyte.

Comparison of Electromagnetic and Marangoni Forces on Thin Coatings during Rapid Heating Process

NASA Astrophysics Data System (ADS)

Steinberg, T.; Opitz, T.; Rybakov, A.; Baake, E.

2018-05-01

The present paper is dedicated to the investigation of Marangoni and Lorentz forces in a rapid heating process. During the melting of aluminum-silicon (AlSi) layer on the bor-manganese steel 22MnB5, the liquid AlSi is shifting from the middle to the side and leaves dry spots on the steel due to a combination of both forces. In order to solve this process design issue, the impact of each force in the process will be evaluated. Evaluation is carried out using experimental data and numerical simulation.

Microfabricated Cantilevers Based on Sputtered Thin-Film Ni50Ti50 Shape Memory Alloy (SMA)

DTIC Science & Technology

2015-08-01

surface coating developed during the NiTi deposition or anneal that is relatively resistant to the wet etch. Fig. 2 SEMs after the NiTi wet -etch...SEMs of NiTi devices after the 600 °C anneal , wet -etch patterning of the NiTi. A 120-nm Au capping layer was also sputtered. Figure 3a shows a 200-nm...Ni50Ti50 Cantilever 2 3. Results and Discussion 3 3.1 Wet -Etch Patterning NiTi 3 3.2 Dry-Etch Release of NiTi Devices 5 3.3 Thermal Actuation of

Standardisation of Gymnema sylvestre r. Br. with reference to gymnemagenin by high-performance thin-layer chromatography.

PubMed

Puratchimani, V; Jha, S

2004-01-01

A simple and reproducible HPTLC method for the determination of gymnemagenin (1) in Gymnema sylvestre has been developed. Components were separated on pre-coated silica gel 60 F254 plates with chloroform:methanol (9:1) and scanned using a densitometric scanner in the UV reflectance mode at 290 nm. Linearity of determination of 1 was observed in the range 4-10 microg. The average percentage recovery of 1 from an extract was 99.09 +/- 0.29, and the content of 1 in leaves of the title plant was 1.61% (dry weight).

Clean Air Slots Amid Dense Atmospheric Pollution in Southern Africa

NASA Technical Reports Server (NTRS)

Hobbs, Peter V.

2003-01-01

During the flights of the University of Washington's Convair-580 in the Southern African Regional Science Initiative (SAFARI 2000) in southern Africa, a phenomenon was observed that has not been reported previously. This was the occurrence of thin layers of remarkably clean air, sandwiched between heavily polluted air, which persisted for many hours during the day. Photographs are shown of these clean air slots (CAS), and particle concentrations and light scattering coefficients in and around such slot are presented. An explanation is proposed for the propensity of CAS to form in southern Africa during the dry season.

An Electrochemical Experiment Using an Optically Transparent Thin Layer Electrode

ERIC Educational Resources Information Center

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)

Rectenna that converts infrared radiation to electrical energy

DOEpatents

Davids, Paul; Peters, David W.

2016-09-06

Technologies pertaining to converting infrared (IR) radiation to DC energy are described herein. In a general embodiment, a rectenna comprises a conductive layer. A thin insulator layer is formed on the conductive layer, and a nanoantenna is formed on the thin insulator layer. The thin insulator layer acts as a tunnel junction of a tunnel diode.

Influence of different aspect ratios on the structural and electrical properties of GaN thin films grown on nanoscale-patterned sapphire substrates

NASA Astrophysics Data System (ADS)

Lee, Fang-Wei; Ke, Wen-Cheng; Cheng, Chun-Hong; Liao, Bo-Wei; Chen, Wei-Kuo

2016-07-01

This study presents GaN thin films grown on nanoscale-patterned sapphire substrates (NPSSs) with different aspect ratios (ARs) using a homemade metal-organic chemical vapor deposition system. The anodic aluminum oxide (AAO) technique is used to prepare the dry etching mask. The cross-sectional view of the scanning electron microscope image shows that voids exist between the interface of the GaN thin film and the high-AR (i.e. ∼2) NPSS. In contrast, patterns on the low-AR (∼0.7) NPSS are filled full of GaN. The formation of voids on the high-AR NPSS is believed to be due to the enhancement of the lateral growth in the initial growth stage, and the quick-merging GaN thin film blocks the precursors from continuing to supply the bottom of the pattern. The atomic force microscopy images of GaN on bare sapphire show a layer-by-layer surface morphology, which becomes a step-flow surface morphology for GaN on a high-AR NPSS. The edge-type threading dislocation density can be reduced from 7.1 × 108 cm-2 for GaN on bare sapphire to 4.9 × 108 cm-2 for GaN on a high-AR NPSS. In addition, the carrier mobility increases from 85 cm2/Vs for GaN on bare sapphire to 199 cm2/Vs for GaN on a high-AR NPSS. However, the increased screw-type threading dislocation density for GaN on a low-AR NPSS is due to the competition of lateral growth on the flat-top patterns and vertical growth on the bottom of the patterns that causes the material quality of the GaN thin film to degenerate. Thus, the experimental results indicate that the AR of the particular patterning of a NPSS plays a crucial role in achieving GaN thin film with a high crystalline quality.

Direct Numerical Simulation of Wetting and Spreading Behavior on Heterogeneous and Roughened Substrates

NASA Technical Reports Server (NTRS)

Schwartz, Leonard W.

1999-01-01

A method of calculation is presented that allows the simulation of the time-dependent three-dimensional motion of thin liquid layers on solid substrates for systems with finite equilibrium contact angles. The contact angle is a prescribed function of position on the substrate. Similar mathematical models are constructed for substrates with a pattern of roughness. Evolution equations are given, using the lubrication approximation, that include viscous, capillary and disjoining forces. Motion to and from dry substrate regions is made possible by use of a thin energetically-stable wetting layer. We simulate motion on heterogeneous substrates with periodic arrays of high contact-angle patches. Two different problems are treated for heterogenous substrates. The first is spontaneous motion driven only by wetting forces. If the contact-angle difference is sufficiently high, the droplet can find several different stable positions, depending on the previous history of the motion. A second simulation treats a forced cyclical motion. Energy dissipation per cycle for a heterogeneous substrate is found to be larger than for a uniform substrate with the same total energy. The Landau-Levich solution for plate removal from a liquid bath is extended to account for a pattern of roughness on the plate.

Analysis of phytochemical profile of Terminalia arjuna bark extract with antioxidative and antimicrobial properties

PubMed Central

Mandal, Shreya; Patra, Arpita; Samanta, Animesh; Roy, Suchismita; Mandal, Arpita; Mahapatra, Tapasi Das; Pradhan, Shrabani; Das, Koushik; Nandi, Dilip Kumar

2013-01-01

Objective To investigate phytochemical screening, antimicrobial activity and qualitative thin layer chromatographic separation of flavonoid components, antioxidant activity and total flavonoid compound of Terminalia arjuna. Methods For phytochemical screening, some common and available standard tests were done. Antimicrobial bioassay was done through agar well diffusion method. Detection of antioxidant activity and flavonoid compounds were done through thin layer chromatography. Total antioxidant activity was measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) in colorimetric method. Aluminum chloride colorimetric method was used for total flavonoid determination. Results Phytochemical screening showed the active compounds presence in high concentration, such as phytosterol, lactones, flavonoids, phenolic compounds and tannins and glycosides. The antimicrobial activity of extract showed that greater inhibition zone against Gram negative bacteria than Gram positive bacteria. This methanolic extract showed a promising antioxidant activity, as absorption of DPPH redicles decreased in DPPH free radical scavenging assay. Flavonoids components having antioxidant property present in the methanol extract at a level of 199.00 mg quercetin equivalent/g of dried methanol extract in colorimetric method. Conclusions The Terminalia arjuna bark extract revealed the presence of bio-active constituents which are known to exhibit medicinal as well as physiological activities. PMID:24093787

A facile method to enhance the uniformity and adhesion properties of water-based ceramic coating layers on hydrophobic polyethylene separators

NASA Astrophysics Data System (ADS)

Lee, Hoogil; Jeon, Hyunkyu; Gong, Seokhyeon; Ryou, Myung-Hyun; Lee, Yong Min

2018-01-01

To enhance the uniformity and adhesion properties of water-based ceramic coating layers on hydrophobic polyethylene (PE) separators, their surfaces were treated with thin and hydrophilic polydopamine layers. As a result, an aqueous ceramic coating slurry consisting of Al2O3 particles, carboxyl methyl cellulose (CMC) binders, and water solvent was easily spread on the separator surface, and a uniform ceramic layer was formed after solvent drying. Moreover, the ceramic coating layer showed greatly improved adhesion properties to the PE separator surface. Whereas the adhesion strength within the bulk coating layer (Fmid) ranged from 43 to 86 N m-1 depending on the binder content of 1.5-3.0 wt%, the adhesion strength at the interface between the ceramic coating layer and PE separator (Fsepa-Al2O3) was 245-360 N m-1, a value equivalent to an increase of four or five times. Furthermore, an additional ceramic coating layer of approximately 7 μm did not degrade the ionic conductivity and electrochemical properties of the bare PE separators. Thus, all the LiMn2O4/graphite cells with ceramic-coated separators delivered an improved cycle life and rate capability compared with those of the control cells with bare PE separators.

Pharmacognostic Specification, Chlorogenic Acid Content, and In vitro Antioxidant Activities of Lonicera japonica Flowering Bud

PubMed Central

Chaowuttikul, Chayanon; Palanuvej, Chanida; Ruangrungsi, Nijsiri

2017-01-01

Background: Lonicera japonica Thunb. or Japanese Honeysuckle has been widely used in traditional medicine for antipyretic. Objective: To establish the pharmacognostic specification of L. japonica flowering bud in Thailand and to determine its chlorogenic acid content and in vitro antioxidant activities. Materials and Methods: Dried L. japonica flowering bud from 15 various herbal drugstores throughout Thailand were investigated for pharmacognostic specification. Their chlorogenic acid contents were quantitatively analyzed by thin layer chromatography (TLC) densitometry with winCATS software. The mobile phase for TLC development consisted of ethyl acetate: formic acid: acetic acid: water (10:1.1:1.1:2.6). Antioxidant activities were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric ion reducing antioxidant power assay, nitric oxide scavenging assay, and β-carotene bleaching assays. Results: Qualified L. japonica flowering bud in Thailand was presented that the contents of loss on drying, total ash, acid-insoluble ash, and water should not be >10.11%, 6.59%, 1.14%, and 10.82% by weight, respectively. The ethanol and water soluble extractive values should not be < 16.46% and 28.88% by weight, respectively. Chlorogenic acid content in L. japonica flowering bud was found to be 2.24 ± 0.50 g/100 g of crude drug. L. japonica flowering bud showed DPPH and nitric oxide scavenging activities as well as reducing power property. Conclusion: This pharmacognostic specification with special reference to the chlorogenic acid content can be used for quality control of L. japonica flowering bud in Thailand. The potential antioxidant of this crude drug was demonstrated in vitro. SUMMARY Pharmacognostic specification of Lonicera japonica flowering bud in Thailand has been establishedThe chlorogenic acid content has been quantified by thin layer chromatography-densitometryThe ethanolic extract of L. japonica flowering bud showed antioxidation potential, especially on reducing power property. Abbreviations Used: TLC: Thin layer chromatography, DPPH: 2,2-diphenyl-1-picrylhydrazyl, FRAP: Ferric ion Reducing Antioxidant Power, WHO: World Health Organization, ICH: International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use; LOD: Limit of detection; LOQ: Limit of quantitation; BHT: Butylated hydroxytoluene; FeSO4: Iron(II) sulfate; DMSO: Dimethyl sulfoxide; TPTZ: 2,4,6-tripyridyl-s-triazine. PMID:28539735

High-performance Thin-layer Chromatographic-densitometric Quantification and Recovery of Bioactive Compounds for Identification of Elite Chemotypes of Gloriosa superba L. Collected from Sikkim Himalayas (India)

PubMed Central

Misra, Ankita; Shukla, Pushpendra Kumar; Kumar, Bhanu; Chand, Jai; Kushwaha, Poonam; Khalid, Md.; Singh Rawat, Ajay Kumar; Srivastava, Sharad

2017-01-01

Background: Gloriosa superba L. (Colchicaceae) is used as adjuvant therapy in gout for its potential antimitotic activity due to high colchicine(s) alkaloids. Objective: This study aimed to develop an easy, cheap, precise, and accurate high-performance thin-layer chromatographic (HPTLC) validated method for simultaneous quantification of bioactive alkaloids (colchicine and gloriosine) in G. superba L. and to identify its elite chemotype(s) from Sikkim Himalayas (India). Methods: The HPTLC chromatographic method was developed using mobile phase of chloroform: acetone: diethyl amine (5:4:1) at λmax of 350 nm. Results: Five germplasms were collected from targeted region, and on morpho-anatomical inspection, no significant variation was observed among them. Quantification data reveal that content of colchicine (Rf: 0.72) and gloriosine (Rf: 0.61) varies from 0.035%–0.150% to 0.006%–0.032% (dry wt. basis). Linearity of method was obtained in the concentration range of 100–400 ng/spot of marker(s), exhibiting regression coefficient of 0.9987 (colchicine) and 0.9983 (gloriosine) with optimum recovery of 97.79 ± 3.86 and 100.023% ± 0.01%, respectively. Limit of detection and limit of quantification were analyzed, respectively, as 6.245, 18.926 and 8.024, 24.316 (ng). Two germplasms, namely NBG-27 and NBG-26, were found to be elite chemotype of both the markers. Conclusion: The developed method is validated in terms of accuracy, recovery, and precision studies as per the ICH guidelines (2005) and can be adopted for the simultaneous quantification of colchicine and gloriosine in phytopharmaceuticals. In addition, this study is relevant to explore the chemotypic variability in metabolite content for commercial and medicinal purposes. SUMMARY An easy, cheap, precise, and accurate high performance thin layer chromatographic (HPTLC) validated method for simultaneous quantification of bioactive alkaloids (colchicine and gloriosine) in G. superba L.Five germplasms were collected from targeted region, and on morpho anatomical inspection, no significant variation was observed among themQuantification data reveal that content of colchicine (Rf: 0.72) and gloriosine (Rf: 0.61) varies from 0.035%–0.150% to 0.006%–0.032% (dry wt. basis)Two germplasms, namely NBG 27 and NBG 26, were found to be elite chemotype of both the markers. PMID:29142436

High-performance Thin-layer Chromatographic-densitometric Quantification and Recovery of Bioactive Compounds for Identification of Elite Chemotypes of Gloriosa superba L. Collected from Sikkim Himalayas (India).

PubMed

Misra, Ankita; Shukla, Pushpendra Kumar; Kumar, Bhanu; Chand, Jai; Kushwaha, Poonam; Khalid, Md; Singh Rawat, Ajay Kumar; Srivastava, Sharad

2017-10-01

Gloriosa superba L. (Colchicaceae) is used as adjuvant therapy in gout for its potential antimitotic activity due to high colchicine(s) alkaloids. This study aimed to develop an easy, cheap, precise, and accurate high-performance thin-layer chromatographic (HPTLC) validated method for simultaneous quantification of bioactive alkaloids (colchicine and gloriosine) in G. superba L. and to identify its elite chemotype(s) from Sikkim Himalayas (India). The HPTLC chromatographic method was developed using mobile phase of chloroform: acetone: diethyl amine (5:4:1) at λ max of 350 nm. Five germplasms were collected from targeted region, and on morpho-anatomical inspection, no significant variation was observed among them. Quantification data reveal that content of colchicine ( R f : 0.72) and gloriosine ( R f : 0.61) varies from 0.035%-0.150% to 0.006%-0.032% (dry wt. basis). Linearity of method was obtained in the concentration range of 100-400 ng/spot of marker(s), exhibiting regression coefficient of 0.9987 (colchicine) and 0.9983 (gloriosine) with optimum recovery of 97.79 ± 3.86 and 100.023% ± 0.01%, respectively. Limit of detection and limit of quantification were analyzed, respectively, as 6.245, 18.926 and 8.024, 24.316 (ng). Two germplasms, namely NBG-27 and NBG-26, were found to be elite chemotype of both the markers. The developed method is validated in terms of accuracy, recovery, and precision studies as per the ICH guidelines (2005) and can be adopted for the simultaneous quantification of colchicine and gloriosine in phytopharmaceuticals. In addition, this study is relevant to explore the chemotypic variability in metabolite content for commercial and medicinal purposes. An easy, cheap, precise, and accurate high performance thin layer chromatographic (HPTLC) validated method for simultaneous quantification of bioactive alkaloids (colchicine and gloriosine) in G. superba L.Five germplasms were collected from targeted region, and on morpho anatomical inspection, no significant variation was observed among themQuantification data reveal that content of colchicine (Rf: 0.72) and gloriosine (Rf: 0.61) varies from 0.035%-0.150% to 0.006%-0.032% (dry wt. basis)Two germplasms, namely NBG 27 and NBG 26, were found to be elite chemotype of both the markers.

The threshold strength of laminar ceramics utilizing molar volume changes and porosity

NASA Astrophysics Data System (ADS)

Pontin, Michael Gene

It has been shown that uniformly spaced thin compressive layers within a ceramic body can arrest the propagation of an otherwise catastrophic crack, producing a threshold strength: a strength below which the probability of failure is zero. Previous work has shown that the threshold strength increases with both the magnitude of the compressive stress and the fracture toughness of the thin layer material, and finite element analysis predicts that the threshold strength can be further increased when the elastic modulus of the compressive layer is much smaller than the thicker layer. The current work describes several new approaches to increase the threshold strength of a laminar ceramic system. The initial method utilized a molar volume expansion within the thin layers, produced by the tetragonal-to-monoclinic phase transformation of unstabilized zirconia during cooling, in order to produce large compressive stresses within the thin layers. High threshold strengths were measured for this system, but they remained relatively constant as the zirconia content was increased. It was determined that microcracking produced during the transformation reduced the magnitude of the compressive stresses, but may also have served to reduce the modulus of the thin compressive layer, providing an additional strengthening mechanism. The second approach studied the addition of porosity to reduce the elastic modulus of the thin compressive layers. A new processing method was created and analyzed, in which thick layers of the laminate were fabricated by tape-casting, and then dip-coated into a slurry, containing rice starch, to create thin porous compressive layers upon densification. The effects of porosity on the residual compressive stress, elastic modulus, and fracture toughness of the thin layers were measured and calculated, and it was found that the elastic modulus mismatch between the thin and thick layers produced a large strengthening effect for volume fractions of porosity below a critical level. Specimens with greater volume fractions of porosity exhibited complete crack arrest, typically followed by non-catastrophic failure, as cracks initiating in adjacent thick layers coalesced by cracking or delamination along the thin porous layers.

Fault gouge rheology under confined, high-velocity conditions

NASA Astrophysics Data System (ADS)

Reches, Z.; Madden, A. S.; Chen, X.

2012-12-01

We recently developed the experimental capability to investigate the shear properties of fine-grain gouge under confined conditions and high-velocity. The experimental system includes a rotary apparatus that can apply large displacements of tens of meters, slip velocity of 0.001- 2.0 m/s, and normal stress of 35 MPa (Reches and Lockner, 2010). The key new component is a Confined ROtary Cell (CROC) that can shear a gouge layer either dry or under pore-pressure. The pore pressure is controlled by two syringe pumps. CROC includes a ring-shape gouge chamber of 62.5 mm inner diameter, 81.25 mm outer diameter, and up to 3 mm thick gouge sample. The lower, rotating part of CROC contains the sample chamber, and the upper, stationary part includes the loading, hollow cylinder and setting for temperature, and dilation measurements, and pore-pressure control. Each side of the gouge chamber has two pairs of industrial, spring-energized, self-lubricating, teflon-graphite seals, built for particle media and can work at temperature up to 250 ded C. The space between each of the two sets of seals is pressurized by nitrogen. This design generates 'zero-differential pressure' on the inner seal (which is in contact with the gouge powder), and prevents gouge leaks. For the preliminary dry experiments, we used ~2.0 mm thick layers of room-dry kaolinite powder. Total displacements were on the order of meters and normal stress up to 4 MPa. The initial shear was accommodated by multiple internal slip surfaces within the kaolinite layer accommodated as oriented Riedel shear structures. Later, the shear was localized within a thin, plate-parallel Y-surface. The kaolinite layer was compacted at a quasi-asymptotic rate, and displayed a steady-state friction coefficient of ~ 0.5 with no clear dependence on slip velocity up to 0.15 m/s. Further experiments with loose quartz sand (grain size ~ 125 micron) included both dry runs and pore-pressure (distilled water) controlled runs. The sand was pressurized through a porous metal (Mott) plug. Comparison with effective stress calculations indicates the same friction coefficient of ~ 1.0 for the sand layer under dry and pressurized conditions. Both kaolinite and quartz sand experiments developed localized shear zones that were examined at the nano- and micro- scales with AFM, SEM and TEM. These zones displayed reduced grain sizes and cementation by local agglomeration. Kaolinite grains sheared in CROC experiment; scale bar = 1 micron.

Characterization of Cu buffer layers for growth of L10-FeNi thin films

NASA Astrophysics Data System (ADS)

Mizuguchi, M.; Sekiya, S.; Takanashi, K.

2010-05-01

A Cu(001) layer was fabricated on a Au(001) layer to investigate the use of Cu as a buffer layer for growing L10-FeNi thin films. The epitaxial growth of a Cu buffer layer was observed using reflection high-energy electron diffraction. The flatness of the layer improved drastically with an increase in the substrate temperature although the layer was an alloy (AuCu3). An FeNi thin film was epitaxially grown on the AuCu3 buffer layer by alternate monatomic layer deposition and the formation of an L10-FeNi ordered alloy was expected. The AuCu3 buffer layer is thus a promising candidate material for the growth of L10-FeNi thin films.

Image analysis and green tea color change kinetics during thin-layer drying.

PubMed

Shahabi, Mohammad; Rafiee, Shahin; Mohtasebi, Seyed Saeid; Hosseinpour, Soleiman

2014-09-01

This study was conducted to investigate the effect of air temperature and air flow velocity on kinetics of color parameter changes during hot-air drying of green tea, to obtain the best model for hot-air drying of green tea, to apply a computer vision system and to study the color changes during drying. In the proposed computer vision system system, at first RGB values of the images were converted into XYZ values and then to Commission International d'Eclairage L*a*b* color coordinates. The obtained color parameters of L*, a* and b* were calibrated with Hunter-Lab colorimeter. These values were also used for calculation of the color difference, chroma, hue angle and browning index. The values of L* and b* decreased, while the values of a* and color difference (ΔE*ab ) increased during hot-air drying. Drying data were fitted to three kinetic models. Zero, first-order and fractional conversion models were utilized to describe the color changes of green tea. The suitability of fitness was determined using the coefficient of determination (R (2)) and root-mean-square error. Results showed that the fraction conversion model had more acceptable fitness than the other two models in most of color parameters. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

High mobility bottom gate InGaZnO thin film transistors with SiOx etch stopper

NASA Astrophysics Data System (ADS)

Kim, Minkyu; Jeong, Jong Han; Lee, Hun Jung; Ahn, Tae Kyung; Shin, Hyun Soo; Park, Jin-Seong; Jeong, Jae Kyeong; Mo, Yeon-Gon; Kim, Hye Dong

2007-05-01

The authors report on the fabrication of thin film transistors (TFTs), which use an amorphous indium gallium zinc oxide (a-IGZO) channel, by rf sputtering at room temperature and for which the channel length and width are patterned by photolithography and dry etching. To prevent plasma damage to the active channel, a 100-nm-thick SiOx layer deposited by plasma enhanced chemical vapor deposition was adopted as an etch stopper structure. The a-IGZO TFT (W /L=10μm/50μm) fabricated on glass exhibited a high field-effect mobility of 35.8cm2/Vs, a subthreshold gate swing value of 0.59V/decade, a thrseshold voltage of 5.9V, and an Ion/off ratio of 4.9×106, which is acceptable for use as the switching transistor of an active-matrix TFT backplane.

Atomically Thin Mesoporous Nanomesh of Graphitic C₃N₄ for High-Efficiency Photocatalytic Hydrogen Evolution.

PubMed

Han, Qing; Wang, Bing; Gao, Jian; Cheng, Zhihua; Zhao, Yang; Zhang, Zhipan; Qu, Liangti

2016-02-23

Delamination of layer materials into two-dimensional single-atom sheets has induced exceptional physical properties, including large surface area, ultrahigh intrinsic carrier mobility, pronounced changes in the energy band structure, and other properties. Here, atomically thin mesoporous nanomesh of graphitic carbon nitride (g-C3N4) is fabricated by solvothermal exfoliation of mesoporous g-C3N4 bulk made from thermal polymerization of freeze-drying assembled Dicyandiamide nanostructure precursor. With the unique structural advantages for aligned energy levels, electron transfer, light harvesting, and the richly available reaction sites, the as-prepared monolayer of mesoporous g-C3N4 nanomesh exhibits a superior photocatalytic hydrogen evolution rate of 8510 μmol h(-1) g(-1) under λ > 420 nm and an apparent quantum efficiency of 5.1% at 420 nm, the highest of all the metal-free g-C3N4 nanosheets photocatalysts.

Ceramic Composite Thin Films

NASA Technical Reports Server (NTRS)

Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor); Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor)

2013-01-01

A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

Thin-layer voltammetry of soluble species on screen-printed electrodes: proof of concept.

PubMed

Botasini, S; Martí, A C; Méndez, E

2016-10-17

Thin-layer diffusion conditions were accomplished on screen-printed electrodes by placing a controlled-weight onto the cast solution and allowing for its natural spreading. The restricted diffusive conditions were assessed by cyclic voltammetry at low voltage scan rates and electrochemical impedance spectroscopy. The relationship between the weight exerted over the drop and the thin-layer thickness achieved was determined, in such a way that the simple experimental set-up designed for this work could be developed into a commercial device with variable control of the thin-layer conditions. The experimental results obtained resemble those reported for the voltammetric features of electroactive soluble species employing electrodes modified with carbon nanotubes or graphene layers, suggesting that the attainment of the benefits reported for these nanomaterials could be done simply by forcing the solution to spread over the screen-printed electrodic system to form a thin layer solution. The advantages of thin-layer voltammetry in the kinetic characterization of quasi-reversible and irreversible processes are highlighted.

Thermal insulation for high temperature microwave sintering operations and method thereof

DOEpatents

Holcombe, Cressie E.; Dykes, Norman L.; Morrow, Marvin S.

1995-01-01

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering.

Method of preparing thermal insulation for high temperature microwave sintering operations

DOEpatents

Holcombe, Cressie E.; Dykes, Norman L.; Morrow, Marvin S.

1996-01-01

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering.

Selective enhancement of carbohydrate ion abundances by diamond nanoparticles for mass spectrometric analysis.

PubMed

Wu, Chieh-Lin; Wang, Chia-Chen; Lai, Yin-Hung; Lee, Hsun; Lin, Jia-Der; Lee, Yuan Tseh; Wang, Yi-Sheng

2013-04-16

Diamond nanoparticles (DNPs) were incorporated into matrix-assisted laser desorption/ionization (MALDI) samples to enhance the sensitivity of the mass spectrometer to carbohydrates. The DNPs optimize the MALDI sample morphology and thermalize the samples for thermally labile compounds because they have a high thermal conductivity, a low extinction coefficient in UV-vis spectral range, and stable chemical properties. The best enhancement effect was achieved when matrix, DNP, and carbohydrate solutions were deposited and vacuum-dried consecutively to form a trilayer sample morphology. It allows the direct identification of underivatized carbohydrates mixed with equal amount of proteins because no increase in the ion abundance of proteins was achieved. For dextran with an average molecular weight of 1500, the trilayer method typically improves the sensitivity by 79- and 7-fold in comparison to the conventional dried-droplet and thin-layer methods, respectively.

A model for thin layer formation by delayed particle settling at sharp density gradients

NASA Astrophysics Data System (ADS)

Prairie, Jennifer C.; White, Brian L.

2017-02-01

Thin layers - regions where plankton or particles accumulate vertically on scales of a few meters or less - are common in coastal waters, and have important implications for both trophic dynamics and carbon cycling. These features can form by a variety of biological and physical mechanisms, including localized growth, shear-thinning, and directed swimming. An additional mechanism may result in the formation of thin layers of marine aggregates, which have been shown to decrease their settling velocity when passing through sharp density gradients, a behavior termed delayed settling. Here, we apply a simple vertical advection-diffusion model to predict the properties of aggregate thin layers formed by this process. We assume a constant vertical flux of particles from the surface, which is parameterized by observations from laboratory experiments with marine aggregates. The formation, maintenance, and shape of the layers are described in relation to non-dimensional numbers that depend on environmental conditions and particle settling properties. In particular, model results demonstrate layer intensity and sharpness both increase with higher Péclet number (Pe), that is, under conditions with weaker mixing relative to layer formation. Similarly, more intense and sharper layers are found when the delayed settling behavior of aggregates is characterized by a lower velocity minimum. The model also predicts layers that are vertically asymmetric and highly "peaky" when compared with a Gaussian distribution, features often seen in thin layers in natural environments. Lastly, by comparing model predictions with observations of thin layers in the field, we are able to gain some insight into the applicability of delayed settling as a thin layer formation mechanism in different environmental conditions.

Etching Selectivity of Cr, Fe and Ni Masks on Si & SiO2 Wafers

NASA Astrophysics Data System (ADS)

Garcia, Jorge; Lowndes, Douglas H.

2000-10-01

During this Summer 2000 I joined the Semiconductors and Thin Films group led by Dr. Douglas H. Lowndes at Oak Ridge National Laboratory’s Solid State Division. Our objective was to evaluate the selectivity that Trifluoromethane (CHF3), and Sulfur Hexafluoride (SF6) plasmas have for Si, SiO2 wafers and the Ni, Cr, and Fe masks; being this etching selectivity the ratio of the etching rates of the plasmas for each of the materials. We made use of Silicon and Silicon Dioxide-coated wafers that have Fe, Cr or Ni masks. In the semiconductor field, metal layers are often used as masks to protect layers underneath during processing steps; when these wafers are taken to the dry etching process, both the wafer and the mask layers’ thickness are reduced.

Thin Film Transistors On Plastic Substrates

DOEpatents

Carey, Paul G.; Smith, Patrick M.; Sigmon, Thomas W.; Aceves, Randy C.

2004-01-20

A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The silicon based thin film transistor produced by the process includes a low temperature substrate incapable of withstanding sustained processing temperatures greater than about 250.degree. C., an insulating layer on the substrate, a layer of silicon on the insulating layer having sections of doped silicon, undoped silicon, and poly-silicon, a gate dielectric layer on the layer of silicon, a layer of gate metal on the dielectric layer, a layer of oxide on sections of the layer of silicon and the layer of gate metal, and metal contacts on sections of the layer of silicon and layer of gate metal defining source, gate, and drain contacts, and interconnects.

Room temperature rubbing for few-layer two-dimensional thin flakes directly on flexible polymer substrates

PubMed Central

Yu, Yan; Jiang, Shenglin; Zhou, Wenli; Miao, Xiangshui; Zeng, Yike; Zhang, Guangzu; Liu, Sisi

2013-01-01

The functional layers of few-layer two-dimensional (2-D) thin flakes on flexible polymers for stretchable applications have attracted much interest. However, most fabrication methods are “indirect” processes that require transfer steps. Moreover, previously reported “transfer-free” methods are only suitable for graphene and not for other few-layer 2-D thin flakes. Here, a friction based room temperature rubbing method is proposed for fabricating different types of few-layer 2-D thin flakes (graphene, hexagonal boron nitride (h-BN), molybdenum disulphide (MoS2), and tungsten disulphide (WS2)) on flexible polymer substrates. Commercial 2-D raw materials (graphite, h-BN, MoS2, and WS2) that contain thousands of atom layers were used. After several minutes, different types of few-layer 2-D thin flakes were fabricated directly on the flexible polymer substrates by rubbing procedures at room temperature and without any transfer step. These few-layer 2-D thin flakes strongly adhere to the flexible polymer substrates. This strong adhesion is beneficial for future applications. PMID:24045289

Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

NASA Astrophysics Data System (ADS)

M Ali, M. K.; Ruslan, M. H.; Muthuvalu, M. S.; Wong, J.; Sulaiman, J.; Yasir, S. Md.

2014-06-01

The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m2 and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea of this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R2), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested.

Mathematical modelling for the drying method and smoothing drying rate using cubic spline for seaweed Kappaphycus Striatum variety Durian in a solar dryer

DOE Office of Scientific and Technical Information (OSTI.GOV)

M Ali, M. K., E-mail: majidkhankhan@ymail.com, E-mail: eutoco@gmail.com; Ruslan, M. H., E-mail: majidkhankhan@ymail.com, E-mail: eutoco@gmail.com; Muthuvalu, M. S., E-mail: sudaram-@yahoo.com, E-mail: jumat@ums.edu.my

2014-06-19

The solar drying experiment of seaweed using Green V-Roof Hybrid Solar Drier (GVRHSD) was conducted in Semporna, Sabah under the metrological condition in Malaysia. Drying of sample seaweed in GVRHSD reduced the moisture content from about 93.4% to 8.2% in 4 days at average solar radiation of about 600W/m{sup 2} and mass flow rate about 0.5 kg/s. Generally the plots of drying rate need more smoothing compared moisture content data. Special cares is needed at low drying rates and moisture contents. It is shown the cubic spline (CS) have been found to be effective for moisture-time curves. The idea ofmore » this method consists of an approximation of data by a CS regression having first and second derivatives. The analytical differentiation of the spline regression permits the determination of instantaneous rate. The method of minimization of the functional of average risk was used successfully to solve the problem. This method permits to obtain the instantaneous rate to be obtained directly from the experimental data. The drying kinetics was fitted with six published exponential thin layer drying models. The models were fitted using the coefficient of determination (R{sup 2}), and root mean square error (RMSE). The modeling of models using raw data tested with the possible of exponential drying method. The result showed that the model from Two Term was found to be the best models describe the drying behavior. Besides that, the drying rate smoothed using CS shows to be effective method for moisture-time curves good estimators as well as for the missing moisture content data of seaweed Kappaphycus Striatum Variety Durian in Solar Dryer under the condition tested.« less

Polymer thin film as coating layer to prevent corrosion of metal/metal oxide film

NASA Astrophysics Data System (ADS)

Sarkar, Suman; Kundu, Sarathi

2018-04-01

Thin film of polymer is used as coating layer and the corrosion of metal/metal oxide layer is studied with the variation of the thickness of the coating layer. The thin layer of polystyrene is fabricated using spin coating method on copper oxide (CuO) film which is deposited on glass substrate using DC magnetron sputtering technique. Thickness of the polystyrene and the CuO layers are determined using X-ray reflectivity (XRR) technique. CuO thin films coated with the polystyrene layer are exposed to acetic acid (2.5 v/v% aqueous CH3COOH solution) environments and are subsequently analyzed using UV-Vis spectroscopy and atomic force microscopy (AFM). Surface morphology of the film before and after interaction with the acidic environment is determined using AFM. Results obtained from the XRR and UV-Vis spectroscopy confirm that the thin film of polystyrene acts as an anticorrosion coating layer and the strength of the coating depends upon the polymer layer thickness at a constant acid concentration.

Nonenzymatic detection of glucose using BaCuO2 thin layer

NASA Astrophysics Data System (ADS)

Ito, Takeshi; Asada, Tsuyoshi; Asai, Naoto; Shimizu, Tomohiro; Shingubara, Shoso

2017-01-01

A BaCuO2 thin layer was deposited on a glassy carbon electrode and used for the direct oxidation of glucose. The crystalline, electrochemical, and physicochemical properties that depend on the deposition temperature and deposition time were studied. X-ray diffraction (XRD) analysis showed that the thin layer was amorphous even at 400 °C. The current density of the glucose oxidation using the thin layer deposited at 200 °C was higher than those at other deposition temperatures. Under this condition, the current density increased with the glucose concentration and deposition time. These results indicate that a BaCuO2 thin layer has potential for measuring the blood glucose level without enzymes.

Anisotropic membranes for gas separation

DOEpatents

Gollan, A.Z.

1987-07-21

A gas separation membrane has a dense separating layer about 10,000 Angstroms or less thick and a porous support layer 10 to 400 microns thick that is an integral unit with gradually and continuously decreasing pore size from the base of the support layer to the surface of the thin separating layer and is made from a casting solution comprising ethyl cellulose and ethyl cellulose-based blends, typically greater than 47.5 ethoxyl content ethyl cellulose blended with compatible second polymers, such as nitrocellulose. The polymer content of the casting solution is from about 10% to about 35% by weight of the total solution with up to about 50% of this polymer weight a compatible second polymer to the ethyl cellulose in a volatile solvent such as isopropanol, methylacetate, methanol, ethanol, and acetone. Typical nonsolvents for the casting solutions include water and formamide. The casting solution is cast in air from about zero to 10 seconds to allow the volatile solvent to evaporate and then quenched in a coagulation bath, typically water, at a temperature of 7--25 C and then air dried at ambient temperature, typically 10--30 C. 2 figs.

Lithography-free glass surface modification by self-masking during dry etching

NASA Astrophysics Data System (ADS)

Hein, Eric; Fox, Dennis; Fouckhardt, Henning

2011-01-01

Glass surface morphologies with defined shapes and roughness are realized by a two-step lithography-free process: deposition of an ~10-nm-thin lithographically unstructured metallic layer onto the surface and reactive ion etching in an Ar/CF4 high-density plasma. Because of nucleation or coalescence, the metallic layer is laterally structured during its deposition. Its morphology exhibits islands with dimensions of several tens of nanometers. These metal spots cause a locally varying etch velocity of the glass substrate, which results in surface structuring. The glass surface gets increasingly rougher with further etching. The mechanism of self-masking results in the formation of surface structures with typical heights and lateral dimensions of several hundred nanometers. Several metals, such as Ag, Al, Au, Cu, In, and Ni, can be employed as the sacrificial layer in this technology. Choice of the process parameters allows for a multitude of different glass roughness morphologies with individual defined and dosed optical scattering.

Methods for making thin layers of crystalline materials

DOEpatents

Lagally, Max G; Paskiewicz, Deborah M; Tanto, Boy

2013-07-23

Methods for making growth templates for the epitaxial growth of compound semiconductors and other materials are provided. The growth templates are thin layers of single-crystalline materials that are themselves grown epitaxially on a substrate that includes a thin layer of sacrificial material. The thin layer of sacrificial material, which creates a coherent strain in the single-crystalline material as it is grown thereon, includes one or more suspended sections and one or more supported sections.

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

PubMed

Akhtar, Juber; Fareed, Sheeba; Aqil, Mohd

2013-07-01

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.

The immunogenicity of thin-film freeze-dried, aluminum salt-adjuvanted vaccine when exposed to different temperatures.

PubMed

Thakkar, Sachin G; Ruwona, Tinashe B; Williams, Robert O; Cui, Zhengrong

2017-04-03

Insoluble aluminum salts such as aluminum oxyhydroxide have been used for decades as adjuvants in human vaccines, and many vaccines contain aluminum salts as adjuvants. Aluminum salt-adjuvanted vaccines must be managed in cold-chain (2-8° C) during transport and storage, as vaccine antigens in general are too fragile to be stable in ambient temperatures, and unintentional slowing freezing causes irreversible aggregation and permanent damage to the vaccines. Previously, we reported that thin-film freeze-drying can be used to convert vaccines adjuvanted with an aluminum salt from liquid suspension into dry powder without causing particle aggregation or decreasing in immunogenicity following reconstitution. In the present study, using ovalbumin (OVA)-adsorbed Alhydrogel® (i.e. aluminum oxyhydroxide, 2% w/v) as a model vaccine, we showed that the immunogenicity of thin-film freeze-dried OVA-adsorbed Alhydrogel® vaccine powder was not significantly changed after it was exposed for an extended period of time in temperatures as high as 40° C or subjected to repeated slow freezing-and-thawing. It is expected that immunization programs can potentially benefit by integrating thin-film freeze-drying into vaccine preparations.

The immunogenicity of thin-film freeze-dried, aluminum salt-adjuvanted vaccine when exposed to different temperatures

PubMed Central

Thakkar, Sachin G.; Ruwona, Tinashe B.; Williams, Robert O.; Cui, Zhengrong

2017-01-01

ABSTRACT Insoluble aluminum salts such as aluminum oxyhydroxide have been used for decades as adjuvants in human vaccines, and many vaccines contain aluminum salts as adjuvants. Aluminum salt-adjuvanted vaccines must be managed in cold-chain (2–8° C) during transport and storage, as vaccine antigens in general are too fragile to be stable in ambient temperatures, and unintentional slowing freezing causes irreversible aggregation and permanent damage to the vaccines. Previously, we reported that thin-film freeze-drying can be used to convert vaccines adjuvanted with an aluminum salt from liquid suspension into dry powder without causing particle aggregation or decreasing in immunogenicity following reconstitution. In the present study, using ovalbumin (OVA)-adsorbed Alhydrogel® (i.e. aluminum oxyhydroxide, 2% w/v) as a model vaccine, we showed that the immunogenicity of thin-film freeze-dried OVA-adsorbed Alhydrogel® vaccine powder was not significantly changed after it was exposed for an extended period of time in temperatures as high as 40° C or subjected to repeated slow freezing-and-thawing. It is expected that immunization programs can potentially benefit by integrating thin-film freeze-drying into vaccine preparations. PMID:28051903

Selective Dry Etch for Defining Ohmic Contacts for High Performance ZnO TFTs

DTIC Science & Technology

2014-03-27

scale, high-frequency ZnO thin - film transistors (TFTs) could be fabricated. Molybdenum, tantalum, titanium tungsten 10-90, and tungsten metallic contact... thin - film transistor layout utilized in the thesis research . . . . . 42 3.4 Process Flow Diagram for Optical and e-Beam Devices...TFT thin - film transistor TLM transmission line model UV ultra-violet xvii SELECTIVE DRY ETCH FOR DEFINING OHMIC CONTACTS FOR HIGH PERFORMANCE ZnO TFTs

[Abnormal of tear lipid layer and recent advances in clinical study of dry eye].

PubMed

Xiao, Xin-Ye; Liu, Zu-Guo

2012-03-01

Dry eye is a common disease in the ophthalmological clinic, which is related to the dysfunction of tear film. The tear film is composed of lipid layer, aqueous layer and mucin layer (or lipid layer, aqueous/mucin layer). The lipid of the outmost layer derived from Meibomian gland and distributed on the tear film after blinking can decrease the evaporation and stabilize the tear film. The thickness, quality, and distribution of lipid layer are impaired in many dry eye patients, hence restoring the physiological function of lipid layer may be crucial for the treatment of this kind of dry eye. The lipid artificial tears manifest great effects on increasing lipid layer thickness, stabilizing tear film, improving Meibomian gland dysfunction, and promoting tear film distribution.

Precipitation hydrometeor type relative to the mesoscale airflow in mature oceanic deep convection of the Madden-Julian Oscillation

DOE PAGES

Barnes, Hannah C.; Houze, Robert A.

2014-12-25

We present that composite analysis of mature near-equatorial oceanic mesoscale convective systems (MCSs) during the active stage of the Madden-Julian Oscillation (MJO) shows where different hydrometeor types occur relative to convective updraft and stratiform midlevel inflow layers. The National Center for Atmospheric Research (NCAR) S-PolKa radar observed these MCSs during the Dynamics of the Madden-Julian Oscillation/Atmospheric Radiation Measurement-MJO Investigation Experiment (DYNAMO/AMIE). NCAR's particle identification algorithm (PID) is applied to S-PolKa's polarimetric data to identify the dominant hydrometeor type in each radar sample volume. Combining S-PolKa's Doppler velocity data with the PID demonstrates that hydrometeors have a systematic relationship to themore » airflow within mature MCSs. In the convective region, moderate rain occurs within the updraft core; the heaviest rain occurs just downwind of the core; wet aggregates occur immediately below the melting layer; narrow zones containing graupel/rimed aggregates occur just downstream of the updraft core at midlevels; dry aggregates dominate above the melting level; and smaller ice particles occur along the edges of the convective zone. In the stratiform region, rain intensity decreases toward the anvil; melting aggregates occur in horizontally extensive but vertically thin regions at the melting layer; intermittent pockets of graupel/rimed aggregates occur atop the melting layer; dry aggregates and small ice particles occur sequentially above the melting level; and horizontally oriented ice crystals occur between -10°C and -20°C in turbulent air above the descending midlevel inflow, suggesting enhanced depositional growth of dendrites. Finally, the organization of hydrometeors within the midlevel inflow layer is insensitive to the presence or absence of a leading convective line.« less

A novel technique for the production of cool colored concrete tile and asphalt shingle roofing products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul

The widespread use of solar-reflective roofing materials can save energy, mitigate urban heat islands and slow global warming by cooling the roughly 20% of the urban surface that is roofed. In this study we created prototype solar-reflective nonwhite concrete tile and asphalt shingle roofing materials using a two-layer spray coating process intended to maximize both solar reflectance and factory-line throughput. Each layer is a thin, quick-drying, pigmented latex paint based on either acrylic or a poly(vinylidene fluoride)/acrylic blend. The first layer is a titanium dioxide rutile white basecoat that increases the solar reflectance of a gray-cement concrete tile from 0.18more » to 0.79, and that of a shingle surfaced with bare granules from 0.06 to 0.62. The second layer is a 'cool' color topcoat with weak near-infrared (NIR) absorption and/or strong NIR backscattering. Each layer dries within seconds, potentially allowing a factory line to pass first under the white spray, then under the color spray. We combined a white basecoat with monocolor topcoats in various shades of red, brown, green and blue to prepare 24 cool color prototype tiles and 24 cool color prototypes shingles. The solar reflectances of the tiles ranged from 0.26 (dark brown; CIELAB lightness value L* = 29) to 0.57 (light green; L* = 76); those of the shingles ranged from 0.18 (dark brown; L* = 26) to 0.34 (light green; L* = 68). Over half of the tiles had a solar reflectance of at least 0.40, and over half of the shingles had a solar reflectance of at least 0.25.« less

Improvement in temperature dependence and dielectric tunability properties of PbZr0.52Ti0.48O3 thin films using Ba(Mg1/3Ta2/3)O3 buffer layer

NASA Astrophysics Data System (ADS)

Wu, Zhi; Zhou, Jing; Chen, Wen; Shen, Jie; Yang, Huimin; Zhang, Shisai; Liu, Yueli

2016-12-01

In this paper, Pb(Zr0.52Ti0.48)O3 (PZT) thin films were prepared via sol-gel method. The effects of Ba(Mg1/3Ta2/3)O3 (BMT) buffer layer on the temperature dependence and dielectric tunability properties of PZT thin films were studied. As the thickness of BMT buffer layer increases, the tan δ and tunability of PZT thin films decrease while tunability still maintains above 10%. This result shows that BMT buffer layer can improve the dielectric tunability properties of PZT thin films. Furthermore, the temperature coefficient of the dielectric constant decreases from 2333.4 to 906.9 ppm/°C with the thickness of BMT buffer layer increasing in the range from 25 to 205 °C, indicating that BMT buffer layer can improve the temperature stability of PZT thin films. Therefore, BMT buffer layer plays a critical role in improving temperature dependence and dielectric tunability properties of PbZr0.52Ti0.48O3 thin films.

Breakthrough to Non-Vacuum Deposition of Single-Crystal, Ultra-Thin, Homogeneous Nanoparticle Layers: A Better Alternative to Chemical Bath Deposition and Atomic Layer Deposition

PubMed Central

Liao, Yu-Kuang; Liu, Yung-Tsung; Hsieh, Dan-Hua; Shen, Tien-Lin; Hsieh, Ming-Yang; Tzou, An-Jye; Chen, Shih-Chen; Tsai, Yu-Lin; Lin, Wei-Sheng; Chan, Sheng-Wen; Shen, Yen-Ping; Cheng, Shun-Jen; Chen, Chyong-Hua; Wu, Kaung-Hsiung; Chen, Hao-Ming; Kuo, Shou-Yi; Charlton, Martin D. B.; Hsieh, Tung-Po; Kuo, Hao-Chung

2017-01-01

Most thin-film techniques require a multiple vacuum process, and cannot produce high-coverage continuous thin films with the thickness of a few nanometers on rough surfaces. We present a new ”paradigm shift” non-vacuum process to deposit high-quality, ultra-thin, single-crystal layers of coalesced sulfide nanoparticles (NPs) with controllable thickness down to a few nanometers, based on thermal decomposition. This provides high-coverage, homogeneous thickness, and large-area deposition over a rough surface, with little material loss or liquid chemical waste, and deposition rates of 10 nm/min. This technique can potentially replace conventional thin-film deposition methods, such as atomic layer deposition (ALD) and chemical bath deposition (CBD) as used by the Cu(In,Ga)Se2 (CIGS) thin-film solar cell industry for decades. We demonstrate 32% improvement of CIGS thin-film solar cell efficiency in comparison to reference devices prepared by conventional CBD deposition method by depositing the ZnS NPs buffer layer using the new process. The new ZnS NPs layer allows reduction of an intrinsic ZnO layer, which can lead to severe shunt leakage in case of a CBD buffer layer. This leads to a 65% relative efficiency increase. PMID:28383488

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

ERIC Educational Resources Information Center

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…

Gyrotactic trapping: A numerical study

NASA Astrophysics Data System (ADS)

Ghorai, S.

2016-04-01

Gyrotactic trapping is a mechanism proposed by Durham et al. ["Disruption of vertical motility by shear triggers formation of thin Phytoplankton layers," Science 323, 1067-1070 (2009)] to explain the formation of thin phytoplankton layer just below the ocean surface. This mechanism is examined numerically using a rational model based on the generalized Taylor dispersion theory. The crucial role of sedimentation speed in the thin layer formation is demonstrated. The effects of variation in different parameters on the thin layer formation are also investigated.

[High performance thin-layer chromatography in specific blood diagnosis (author's transl)].

PubMed

Bernardelli, B; Masotti, G

1976-01-01

Furthering their research into the differentiation of various haemoglobins (both human and animal) with the use of thin layer chromatographic methods, the Authors have applied Kaiser's high performance thin layer chromatography (HPTLC) to the specific diagnosis of blood. Although the method was superior to ascending one-dimensional thin layer chromatography for its sensitivity, Rf reproducibility and much briefer migration times, it did not turn out to be suitable for application to the specific requirements of forensic haematology.

Thin-film metal coated insulation barrier in a Josephson tunnel junction. [Patent application

DOEpatents

Hawkins, G.A.; Clarke, J.

1975-10-31

A highly stable, durable, and reproducible Josephson tunnel junction consists of a thin-film electrode of a hard superconductor, a thin oxide insulation layer over the electrode constituting a Josephson tunnel junction barrier, a thin-film layer of stabilizing metal over the barrier, and a second thin-film hard superconductive electrode over the stabilizing film. The thin stabilizing metal film is made only thick enough to limit penetration of the electrode material through the insulation layer so as to prevent a superconductive short.

Fabrication of Crack-Free Barium Titanate Thin Film with High Dielectric Constant Using Sub-Micrometric Scale Layer-by-Layer E-Jet Deposition.

PubMed

Liang, Junsheng; Li, Pengfei; Wang, Dazhi; Fang, Xu; Ding, Jiahong; Wu, Junxiong; Tang, Chang

2016-01-19

Dense and crack-free barium titanate (BaTiO₃, BTO) thin films with a thickness of less than 4 μm were prepared by using sub-micrometric scale, layer-by-layer electrohydrodynamic jet (E-jet) deposition of the suspension ink which is composed of BTO nanopowder and BTO sol. Impacts of the jet height and line-to-line pitch of the deposition on the micro-structure of BTO thin films were investigated. Results show that crack-free BTO thin films can be prepared with 4 mm jet height and 300 μm line-to-line pitch in this work. Dielectric constant of the prepared BTO thin film was recorded as high as 2940 at 1 kHz at room temperature. Meanwhile, low dissipation factor of the BTO thin film of about 8.6% at 1 kHz was also obtained. The layer-by-layer E-jet deposition technique developed in this work has been proved to be a cost-effective, flexible and easy to control approach for the preparation of high-quality solid thin film.

Addition of silica nanoparticles to tailor the mechanical properties of nanofibrillated cellulose thin films.

PubMed

Eita, Mohamed; Arwin, Hans; Granberg, Hjalmar; Wågberg, Lars

2011-11-15

Over the last decade, the use of nanocellulose in advanced technological applications has been promoted both due the excellent properties of this material in combination with its renewability. In this study, multilayered thin films composed of nanofibrillated cellulose (NFC), polyvinyl amine (PVAm) and silica nanoparticles were fabricated on polydimethylsiloxane (PDMS) using a layer-by-layer adsorption technique. The multilayer build-up was followed in situ by quartz crystal microbalance with dissipation, which indicated that the PVAm-SiO(2)-PVAm-NFC system adsorbs twice as much wet mass material compared to the PVAm-NFC system for the same number of bilayers. This is accompanied with a higher viscoelasticity for the PVAm-SiO(2)-PVAm-NFC system. Ellipsometry indicated a dry-state thickness of 2.2 and 3.4 nm per bilayer for the PVAm-NFC system and the PVAm-SiO(2)-PVAm-NFC system, respectively. Atomic force microscopy height images indicate that in both systems, a porous network structure is achieved. Young's modulus of these thin films was determined by the Strain-Induced Elastic Buckling Instability for Mechanical Measurements (SIEBIMM) technique. The Young's modulus of the PVAm/NFC films was doubled, from 1 to 2 GPa, upon incorporation of silica nanoparticles in the films. The introduction of the silica nanoparticles lowered the refractive index of the films, most probably due to an increased porosity of the films. Copyright © 2011 Elsevier Inc. All rights reserved.

Fabrication of raised and inverted SU8 polymer waveguides

NASA Astrophysics Data System (ADS)

Holland, Anthony S.; Mitchell, Arnan; Balkunje, Vishal S.; Austin, Mike W.; Raghunathan, Mukund K.

2005-01-01

Polymer films with high optical transmission have been investigated for making optical devices for several years. SU8 photoresist and optical adhesives have been investigated for use as thin films for optical devices, not what they were originally designed for. Optical adhesives are typically a one component thermoset polymer and are convenient to use for making thin film optical devices such as waveguides. They are prepared in minutes as thin films unlike SU8, which has to be carefully thermally cured over several hours for optimum results. However SU8 can be accurately patterned to form the geometry of structures required for single mode optical waveguides. SU8 in combination with the lower refractive index optical adhesive films such as UV15 from Master Bond are used to form single and multi mode waveguides. SU8 is photopatternable but we have also used dry etching of the SU8 layer or the other polymer layers e.g. UV15 to form the ribs, ridges or trenches required to guide single modes of light. Optical waveguides were also fabricated using only optical adhesives of different refractive indices. The resolution obtainable is poorer than with SU8 and hence multi mode waveguides are obtained. Loss measurements have been obtained for waveguides of different geometries and material combinations. The process for making polymer waveguides is demonstrated for making large multi mode waveguides and microfluidic channels by scaling the process up in size.

Synthesis and Characterization of BaFe12O19 Thin Films Using Suspension of Nano Powders

NASA Astrophysics Data System (ADS)

Salemizadeh, Saman; Seyyed Ebrahimi, S. A.

BaM thin films have been synthesized by dispersing the dried gel nano powders prepared by Sol-Gel method. The solution was made by dissolving iron nitrate Fe(NO3).9H2O, barium nitrate Ba(NO3)2 and citric acid in deyonized water and methanol. This sol was slowly evaporated until a dried gel was formed. This dried gel was then added to ethylene glycol. The final solution was vigorously shaken and mixed in ultrasonic cleaner for 30 min to disperse particles sufficiently. Then the prepared solution spin coated on Si(110) substrate. The obtained thin films were dried at 120 °C and then calcined at 900 °C for 1 h. The films were characterized using X-ray diffraction (XRD) and vibrating sample magnetometer (VSM).

Performance enhancement in Sb doped Cu(InGa)Se2 thin film solar cell by e-beam evaporation

NASA Astrophysics Data System (ADS)

Chen, Jieyi; Shen, Honglie; Zhai, Zihao; Li, Yufang; Yi, Yunge

2018-03-01

To investigate the effects of Sb doping on the structural and electrical properties of Cu(InGa)Se2 (CIGS) thin films and solar cells, CIGS thin films, prepared by e-beam evaporation on soda-lime glass, were doped with lower and upper Sb layers in the precursor stacks respectively. Change of structure and introduction of stress were observed in the CIGS thin films with upper Sb layer in stack through XRD and Raman measurement. Both crystalline quality and compactness of CIGS thin films were improved by the doping of upper Sb layer in stack and the CIGS thin film showed an optimal structural property with 20 nm Sb layer. Movement of Fermi level of the surface of CIGS thin film after doping of upper Sb layer in stack and electrons transfer between Cu/Cu+ redox couple and CIGS thin films, which provided probability for the substitution of Sb for Cu sites at the surface of CIGS thin films, were proposed to explain the migration of Cu from the surface to the bulk of CIGS thin films. The larger barrier at the CIGS/CdS interface after doping of upper Sb layer in stack made contribution to the increase of VOC of CIGS solar cells. The efficiency of CIGS solar cell was improved from 3.3% to 7.2% after doping with 20 nm upper Sb. Compared to the CIGS solar cell with lower Sb layer in stack, in which an additional Cu2-xSe phase was found, the CIGS solar cell with upper Sb layer in stack possessed a higher efficiency.

Evaluation of double-layer density modulated Si thin films as Li-ion battery anodes

NASA Astrophysics Data System (ADS)

Taha Demirkan, Muhammed; Yurukcu, Mesut; Dursun, Burcu; Demir-Cakan, Rezan; Karabacak, Tansel

2017-10-01

Double-layer density modulated silicon thin films which contain alternating low and high density Si film layers were fabricated by magnetron sputtering. Two different samples consisting of alternating layers of high-density/low-density and low-density/high-density Si thin film layers were investigated as anode electrodes in Li-ion batteries. Si thin film in which the terminating layer at the top is low density Si layer-quoted as low-density/high-density film (LD/HD)- exhibits better performance than Si thin film that has high density layer at the top, -quoted as high-density/low-density (HD/LD). A highly stabilized cycling performance with the specific charge capacities of 2000 mAh g-1 at the 150th cycle at C/2 current density, and 1200 mAh g-1 at the 240th cycle at 10 C current density were observed for the LD/HD Si anode in the presence of fluoroethylene carbonate (FEC) electrolyte additive.

Photovoltaic devices comprising cadmium stannate transparent conducting films and method for making

DOEpatents

Wu, Xuanzhi; Coutts, Timothy J.; Sheldon, Peter; Rose, Douglas H.

1999-01-01

A photovoltaic device having a substrate, a layer of Cd.sub.2 SnO.sub.4 disposed on said substrate as a front contact, a thin film comprising two or more layers of semiconductor materials disposed on said layer of Cd.sub.2 SnO.sub.4, and an electrically conductive film disposed on said thin film of semiconductor materials to form a rear electrical contact to said thin film. The device is formed by RF sputter coating a Cd.sub.2 SnO.sub.4 layer onto a substrate, depositing a thin film of semiconductor materials onto the layer of Cd.sub.2 SnO.sub.4, and depositing an electrically conductive film onto the thin film of semiconductor materials.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nurhandoko, Bagus Endar B., E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com; Rock Fluid Imaging Lab., Bandung; Susilowati, E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com

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 aboutmore » 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.« less

Fabrication of wear-resistant silicon microprobe tips for high-speed surface roughness scanning devices

NASA Astrophysics Data System (ADS)

Wasisto, Hutomo Suryo; Yu, Feng; Doering, Lutz; Völlmeke, Stefan; Brand, Uwe; Bakin, Andrey; Waag, Andreas; Peiner, Erwin

2015-05-01

Silicon microprobe tips are fabricated and integrated with piezoresistive cantilever sensors for high-speed surface roughness scanning systems. The fabrication steps of the high-aspect-ratio silicon microprobe tips were started with photolithography and wet etching of potassium hydroxide (KOH) resulting in crystal-dependent micropyramids. Subsequently, thin conformal wear-resistant layer coating of aluminum oxide (Al2O3) was demonstrated on the backside of the piezoresistive cantilever free end using atomic layer deposition (ALD) method in a binary reaction sequence with a low thermal process and precursors of trimethyl aluminum and water. The deposited Al2O3 layer had a thickness of 14 nm. The captured atomic force microscopy (AFM) image exhibits a root mean square deviation of 0.65 nm confirming the deposited Al2O3 surface quality. Furthermore, vacuum-evaporated 30-nm/200-nm-thick Au/Cr layers were patterned by lift-off and served as an etch mask for Al2O3 wet etching and in ICP cryogenic dry etching. By using SF6/O2 plasma during inductively coupled plasma (ICP) cryogenic dry etching, micropillar tips were obtained. From the preliminary friction and wear data, the developed silicon cantilever sensor has been successfully used in 100 fast measurements of 5- mm-long standard artifact surface with a speed of 15 mm/s and forces of 60-100 μN. Moreover, the results yielded by the fabricated silicon cantilever sensor are in very good agreement with those of calibrated profilometer. These tactile sensors are targeted for use in high-aspect-ratio microform metrology.

Crop drying by indirect active hybrid solar - Electrical dryer in the eastern Algerian Septentrional Sahara

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boughali, S.; Bouchekima, B.; Mennouche, D.

2009-12-15

In the present work, a new specific prototype of an indirect active hybrid solar-electrical dryer for agricultural products was constructed and investigated at LENREZA Laboratory, University of Ouargla (Algerian Sahara). In the new configuration of air drying passage; the study was done in a somewhat high range of mass flow rate between 0.04 and 0.08 kg/m{sup 2} s a range not properly investigated by most researchers. Experimental tests with and without load were performed in winter season in order to study the thermal behavior of the dryer and the effect of high air masse flow on the collector and systemmore » drying efficiency. The fraction of electrical and solar energy contribution versus air mass flow rate was investigated. Slice tomato was studied with different temperatures and velocities of drying air in order to study the influence of these parameters on the removal moisture content from the product and on the kinetics drying and also to determine their suitable values. Many different thin layer mathematical drying models were compared according to their coefficient of determination (R{sup 2}) and reduced chi square ({chi}{sup 2}) to estimate experimental drying curves. The Middli model in this condition proved to be the best for predicting drying behavior of tomato slice with (R{sup 2} = 0.9995, {chi}{sup 2} = 0.0001). Finally an economic evaluation was calculated using the criterion of payback period which is found very small 1.27 years compared to the life of the dryer 15 years. (author)« less

Two-Phase Solid/Fluid Simulation of Dense Granular Flows With Dilatancy Effects

NASA Astrophysics Data System (ADS)

Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Narbona-Reina, Gladys; Kone, El Hadj

2017-04-01

Describing grain/fluid interaction in debris flows models is still an open and challenging issue with key impact on hazard assessment [1]. We present here a two-phase two-thin-layer model for fluidized debris flows that takes into account dilatancy effects. It describes the velocity of both the solid and the fluid phases, the compression/ dilatation of the granular media and its interaction with the pore fluid pressure [2]. The model is derived from a 3D two-phase model proposed by Jackson [3] and the mixture equations are closed by a weak compressibility relation. This relation implies that the occurrence of dilation or contraction of the granular material in the model depends on whether the solid volume fraction is respectively higher or lower than a critical value. When dilation occurs, the fluid is sucked into the granular material, the pore pressure decreases and the friction force on the granular phase increases. On the contrary, in the case of contraction, the fluid is expelled from the mixture, the pore pressure increases and the friction force diminishes. To account for this transfer of fluid into and out of the mixture, a two-layer model is proposed with a fluid or a solid layer on top of the two-phase mixture layer. Mass and momentum conservation are satisfied for the two phases, and mass and momentum are transferred between the two layers. A thin-layer approximation is used to derive average equations. Special attention is paid to the drag friction terms that are responsible for the transfer of momentum between the two phases and for the appearance of an excess pore pressure with respect to the hydrostatic pressure. Interestingly, when removing the role of water, our model reduces to a dry granular flow model including dilatancy. We first compare experimental and numerical results of dilatant dry granular flows. Then, by quantitatively comparing the results of simulation and laboratory experiments on submerged granular flows, we show that our model contains the basic ingredients making it possible to reproduce the interaction between the granular and fluid phases through the change in pore fluid pressure. In particular, we analyse the different time scales in the model and their role in granular/fluid flow dynamics. References [1] R. Delannay, A. Valance, A. Mangeney, O. Roche, P. Richard, J. Phys. D: Appl. Phys., in press (2016). [2] F. Bouchut, E. D. Fernández-Nieto, A. Mangeney, G. Narbona-Reina, J. Fluid Mech., 801, 166-221 (2016). [3] R. Jackson, Cambridges Monographs on Mechanics (2000).

A Leidenfrost Engine

NASA Astrophysics Data System (ADS)

Wells, Gary; Ledesma-Aguillar, Ridrigo; McHale, Glen; Sefiane, Khellil

2015-11-01

The Leidenfrost effect, the sustained levitation of evaporating liquid droplets by a cushion of their on vapour on very hot surfaces, has received increased attention over the past few years. On patterned surfaces, rectification of the vapour layer flow can lead to rich dynamics of evaporating drops or sublimating blocks of dry ice, including self-propulsion, orbiting and conjoint rotation. In this paper we show that the Leidenfrost effect can be exploited to drive the rotation of rigid objects, such as solid hydrophilic plates coupled to water droplets and blocks of dry ice, by using turbine-like substrates. Using a hydrodynamic model, we show that drag-based rotation is achieved at low-Reynolds number by a rectification mechanism of the flow in the vapour layer caused by the underlying turbine-like geometry. Our theoretical model determines the maximum weight of Leidenfrost rotors and the net torque driving their motion in terms of operational parameters, showing an excellent agreement with experiments using dry-ice blocks. We generalise the concept of rotation into a new concept for a heat engine capable of harvesting thermal energy using either thin-film boiling or sublimation as a phase-change mechanism. As a proof principle, we implement the new sublimation engine in the lab to create a simple electromagnetic generator. Our results support the feasibility of low-friction in situ energy harvesting from both liquids and ices in challenging situations such as deep drilling, outer space exploration or micro-mechanical manipulation.

Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

DOEpatents

Ruffner, Judith A.; Bullington, Jeff A.; Clem, Paul G.; Warren, William L.; Brinker, C. Jeffrey; Tuttle, Bruce A.; Schwartz, Robert W.

1999-01-01

A monolithic infrared detector structure which allows integration of pyroelectric thin films atop low thermal conductivity aerogel thin films. The structure comprises, from bottom to top, a substrate, an aerogel insulating layer, a lower electrode, a pyroelectric layer, and an upper electrode layer capped by a blacking layer. The aerogel can offer thermal conductivity less than that of air, while providing a much stronger monolithic alternative to cantilevered or suspended air-gap structures for pyroelectric thin film pixel arrays. Pb(Zr.sub.0.4 Ti.sub.0.6)O.sub.3 thin films deposited on these structures displayed viable pyroelectric properties, while processed at 550.degree. C.

Microstructure and thermochromic properties of VOX-WOX-VOX ceramic thin films

NASA Astrophysics Data System (ADS)

Khamseh, S.; Araghi, H.; Ghahari, M.; Faghihi Sani, M. A.

2016-03-01

W-doped VO2 films have been synthesized via oxygen annealing of V-W-V (vanadium-tungsten-vanadium) multilayered films. The effects of middle layer's thickness of V-W-V multilayered film on structure and properties of VOX-WOX-VOX ceramic thin films were investigated. The as-deposited V-W-V multilayered film showed amorphous-like structure when mixed structure of VO2 (M) and VO2 (B) was formed in VOX-WOX-VOX ceramic thin films. Tungsten content of VOX-WOX-VOX ceramic thin films increased with increasing middle layer's thickness. With increasing middle layer's thickness, room temperature square resistance ( R sq) of VOX-WOX-VOX ceramic thin films increased from 65 to 86 kΩ/sq. The VOX-WOX-VOX ceramic thin film with the thinnest middle layer showed significant SMT (semiconductor-metal transition) when SMT became negligible on increasing middle layer's thickness.

20% Efficient Zn0.9Mg0.1O:Al/Zn0.8Mg0.2O/Cu(In,Ga)(S,Se)2 Solar Cell Prepared by All-Dry Process through a Combination of Heat-Light-Soaking and Light-Soaking Processes.

PubMed

Chantana, Jakapan; Kato, Takuya; Sugimoto, Hiroki; Minemoto, Takashi

2018-04-04

Development of Cd-free Cu(In,Ga)(S,Se) 2 (CIGSSe)-based thin-film solar cells fabricated by an all-dry process is intriguing to minimize optical loss at a wavelength shorter than 520 nm owing to absorption of the CdS buffer layer and to be easily integrated into an in-line process for cost reduction. Cd-free CIGSSe solar cells are therefore prepared by the all-dry process with a structure of Zn 0.9 Mg 0.1 O:Al/Zn 0.8 Mg 0.2 O/CIGSSe/Mo/glass. It is demonstrated that Zn 0.8 Mg 0.2 O and Zn 0.9 Mg 0.1 O:Al are appropriate as buffer and transparent conductive oxide layers with large optical band gap energy values of 3.75 and 3.80 eV, respectively. The conversion efficiency (η) of the Cd-free CIGSSe solar cell without K-treatment is consequently increased to 18.1%. To further increase the η, the Cd-free CIGSSe solar cell with K-treatment is next fabricated and followed by posttreatment called the heat-light-soaking (HLS) + light-soaking (LS) process, including HLS at 110 °C followed by LS under AM 1.5G illumination. It is disclosed that the HLS + LS process gives rise to not only the enhancement of carrier density but also the decrease in the carrier recombination rate at the buffer/absorber interface. Ultimately, the η of the Cd-free CIGSSe solar cell with K-treatment prepared by the all-dry process is enhanced to the level of 20.0%.

Guide to fuel treatments in dry forests of the Western United States: assessing forest structure and fire hazard.

Treesearch

Morris C. Johnson; David L. Peterson; Crystal L. Raymond

2007-01-01

Guide to Fuel Treatments analyzes a range of fuel treatments for representative dry forest stands in the Western United States with overstories dominated by ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), and pinyon pine (Pinus edulis). Six silvicultural options (no thinning; thinning...

Re-Usable Thin-Layer Spectroelectrochemical Cell for Non-Aqueous Solvent Systems.

DTIC Science & Technology

1987-11-01

rapidly reassembied. It can be used under 1-gassei .I I. wIII aquleous solution or a variety of comon rg-an Ic 1 ,+.t r . -, 1 1 soivenrts , u( h as o...for 1 days. Lithium chloride (Anachemia, reagent grade) was dried at 12ooC for 24 h. Water was purified by double distillation over KMnO4, foiluwed by...peak to peaK 3eparatiun witn ;r-’ra.in scan rate from Ib mV at lmV/s to lUU mV at lUU mv/. r-eaK IC , ,:.ik ;eparatiurts measured at several scan rates

System and Method for Fabricating Super Conducting Circuitry on Both Sides of an Ultra-Thin Layer

NASA Technical Reports Server (NTRS)

Brown, Ari D. (Inventor); Mikula, Vilem (Inventor)

2017-01-01

A method of fabricating circuitry in a wafer includes depositing a superconducting metal on a silicon on insulator wafer having a handle wafer, coating the wafer with a sacrificial layer and bonding the wafer to a thermally oxide silicon wafer with a first epoxy. The method includes flipping the wafer, thinning the flipped wafer by removing a handle wafer, etching a buried oxide layer, depositing a superconducting layer, bonding the wafer to a thermally oxidized silicon wafer having a handle wafer using an epoxy, flipping the wafer again, thinning the flipped wafer, etching a buried oxide layer from the wafer and etching the sacrificial layer from the wafer. The result is a wafer having superconductive circuitry on both sides of an ultra-thin silicon layer.

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

DOEpatents

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.

Device and method for luminescence enhancement by resonant energy transfer from an absorptive thin film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akselrod, Gleb M.; Bawendi, Moungi G.; Bulovic, Vladimir

Disclosed are a device and a method for the design and fabrication of the device for enhancing the brightness of luminescent molecules, nanostructures, and thin films. The device includes a mirror, a dielectric medium or spacer, an absorptive layer, and a luminescent layer. The absorptive layer is a continuous thin film of a strongly absorbing organic or inorganic material. The luminescent layer may be a continuous luminescent thin film or an arrangement of isolated luminescent species, e.g., organic or metal-organic dye molecules, semiconductor quantum dots, or other semiconductor nanostructures, supported on top of the absorptive layer.

Advanced germanium layer transfer for ultra thin body on insulator structure

NASA Astrophysics Data System (ADS)

Maeda, Tatsuro; Chang, Wen-Hsin; Irisawa, Toshifumi; Ishii, Hiroyuki; Hattori, Hiroyuki; Poborchii, Vladimir; Kurashima, Yuuichi; Takagi, Hideki; Uchida, Noriyuki

2016-12-01

We present the HEtero-Layer Lift-Off (HELLO) technique to obtain ultra thin body (UTB) Ge on insulator (GeOI) substrates. The transferred ultra thin Ge layers are characterized by the Raman spectroscopy measurements down to the thickness of ˜1 nm, observing a strong Raman intensity enhancement for high quality GeOI structure in ultra thin regime due to quantum size effect. This advanced Ge layer transfer technique enabled us to demonstrate UTB-GeOI nMOSFETs with the body thickness of only 4 nm.

Y1Ba2Cu3O(6+delta) growth on thin Y-enhanced SiO2 buffer layers on silicon

NASA Technical Reports Server (NTRS)

Robin, T.; Mesarwi, A.; Wu, N. J.; Fan, W. C.; Espoir, L.; Ignatiev, A.; Sega, R.

1991-01-01

SiO2 buffer layers as thin as 2 nm have been developed for use in the growth of Y1Ba2Cu3O(6+delta) thin films on silicon substrates. The SiO2 layers are formed through Y enhancement of silicon oxidation, and are highly stoichiometric. Y1Ba2Cu3O(6+delta) film growth on silicon with thin buffer layers has shown c orientation and Tc0 = 78 K.

Photovoltaic devices comprising cadmium stannate transparent conducting films and method for making

DOEpatents

Wu, X.; Coutts, T.J.; Sheldon, P.; Rose, D.H.

1999-07-13

A photovoltaic device is disclosed having a substrate, a layer of Cd[sub 2]SnO[sub 4] disposed on said substrate as a front contact, a thin film comprising two or more layers of semiconductor materials disposed on said layer of Cd[sub 2]SnO[sub 4], and an electrically conductive film disposed on said thin film of semiconductor materials to form a rear electrical contact to said thin film. The device is formed by RF sputter coating a Cd[sub 2]SnO[sub 4] layer onto a substrate, depositing a thin film of semiconductor materials onto the layer of Cd[sub 2]SnO[sub 4], and depositing an electrically conductive film onto the thin film of semiconductor materials. 10 figs.

Layered Organization in the Coastal Ocean: 4-D Assessment of Thin Layer Structure, Dynamics and Impacts

DTIC Science & Technology

2009-09-30

maintenance and dissipation of layers; (2) to understand the spatial coherence and spatial properties of thin layers in the coastal ocean (especially in...ORCAS profilers at K1 South and K2 had a Nortek ADV (Acoustic Doppler Velocity meter) for simultaneously measuring centimeter- scale currents and...year will be used to (1) detect the presence, intensity, thickness, temporal persistence, and spatial coherence of thin optical and acoustical layers

A general synthesis strategy for the multifunctional 3D polypyrrole foam of thin 2D nanosheets

NASA Astrophysics Data System (ADS)

Xue, Jiangli; Mo, Maosong; Liu, Zhuming; Ye, Dapeng; Cheng, Zhihua; Xu, Tong; Qu, Liangti

2018-05-01

A 3D macroporous conductive polymer foam of thin 2D polypyrrole (PPy) nanosheets is developed by adopting a novel intercalation of guest (monomer Py) between the layers of the lamellar host (3D vanadium oxide foam) template-replication strategy. The 3D PPy foam of thin 2D nanosheets exhibits diverse functions including reversible compressibility, shape memory, absorption/adsorption and mechanically deformable supercapacitor characteristics. The as-prepared 3D PPy foam of thin nanosheets is highly light weight with a density of 12 mg·cm-3 which can bear the large compressive strain up to 80% whether in wet or dry states; and can absorb organic solutions or extract dye molecules fast and efficiently. In particular, the PPy nanosheet-based foamas a mechanically deformable electrode material for supercapacitors exhibits high specific capacitance of 70 F·g-1 at a fast charge-discharge rate of 50 mA·g-1, superior to that of any other typical pure PPy-based capacitor. We envision that the strategy presented here should be applicable to fabrication of a wide variety of organic polymer foams and hydrogels of low-dimensional nanostructures and even inorganic foams and hydrogels of low-dimensional nanostructures, and thus allow for exploration of their advanced physical and chemical properties.

A general synthesis strategy for the multifunctional 3D polypyrrole foam of thin 2D nanosheets

NASA Astrophysics Data System (ADS)

Xue, Jiangli; Mo, Maosong; Liu, Zhuming; Ye, Dapeng; Cheng, Zhihua; Xu, Tong; Qu, Liangti

2018-06-01

A 3D macroporous conductive polymer foam of thin 2D polypyrrole (PPy) nanosheets is developed by adopting a novel intercalation of guest (monomer Py) between the layers of the lamellar host (3D vanadium oxide foam) template-replication strategy. The 3D PPy foam of thin 2D nanosheets exhibits diverse functions including reversible compressibility, shape memory, absorption/adsorption and mechanically deformable supercapacitor characteristics. The as-prepared 3D PPy foam of thin nanosheets is highly light weight with a density of 12 mg·cm-3 which can bear the large compressive strain up to 80% whether in wet or dry states; and can absorb organic solutions or extract dye molecules fast and efficiently. In particular, the PPy nanosheet-based foam as a mechanically deformable electrode material for supercapacitors exhibits high specific capacitance of 70 F·g-1 at a fast charge-discharge rate of 50 mA·g-1, superior to that of any other typical pure PPy-based capacitor. We envision that the strategy presented here should be applicable to fabrication of a wide variety of organic polymer foams and hydrogels of low-dimensional nanostructures and even inorganic foams and hydrogels of low-dimensional nanostructures, and thus allow for exploration of their advanced physical and chemical properties.

A tri-layer thin film containing graphene oxide to protect zinc substrates from wear

NASA Astrophysics Data System (ADS)

Wang, Ying; Gu, Zhengpeng; Yuan, Ningyi; Chu, Fuqiang; Cheng, Guanggui; Ding, Jianning

2018-06-01

Due to its excellent properties, Zn alloy is widely used in daily life. However, the poor wear-resisting properties of Zn alloys limits their application. In this paper, a tri-layer thin film consisting of 3-aminopropyltriethoxysilane (APS), graphene oxide (GO) and perfluoropolyethers (PFPE) were successfully prepared on the surface of Zn alloy to improve the wear-resisting properties. The as-prepared tri-layer thin films were characterized by atomic force microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy and contact angle measurement. In addition, the tribological properties of the as-prepared tri-layer thin films were studied on a ball-on-plate tribometer and the morphologies of worn surfaces were observed using 3D noncontact interferometric microscope. Compared with the control samples, the tri-layer thin films showed excellent friction-reducing and wear-resisting properties, which was attributed to the synergistic effect of the GO as the load-carrying layer and the PFPE as the lubricating layer.

Antimicrobial nano-silver non-woven polyethylene terephthalate fabric via an atmospheric pressure plasma deposition process

PubMed Central

Deng, Xiaolong; Yu Nikiforov, Anton; Coenye, Tom; Cools, Pieter; Aziz, Gaelle; Morent, Rino; De Geyter, Nathalie; Leys, Christophe

2015-01-01

An antimicrobial nano-silver non-woven polyethylene terephthalate (PET) fabric has been prepared in a three step process. The fabrics were first pretreated by depositing a layer of organosilicon thin film using an atmospheric pressure plasma system, then silver nano-particles (AgNPs) were incorporated into the fabrics by a dipping-dry process, and finally the nano-particles were covered by a second organosilicon layer of 10-50 nm, which acts as a barrier layer. Different surface characterization techniques like SEM and XPS have been implemented to study the morphology and the chemical composition of the nano-silver fabrics. Based on these techniques, a uniform immobilization of AgNPs in the PET matrix has been observed. The antimicrobial activity of the treated fabrics has also been tested using P. aeruginosa, S. aureus and C. albicans. It reveals that the thickness of the barrier layer has a strong effect on the bacterial reduction of the fabrics. The durability and stability of the AgNPs on the fabrics has also been investigated in a washing process. By doing so, it is confirmed that the barrier layer can effectively prevent the release of AgNPs and that the thickness of the barrier layer is an important parameter to control the silver ions release. PMID:25951432

Fabrication of Crack-Free Barium Titanate Thin Film with High Dielectric Constant Using Sub-Micrometric Scale Layer-by-Layer E-Jet Deposition

PubMed Central

Liang, Junsheng; Li, Pengfei; Wang, Dazhi; Fang, Xu; Ding, Jiahong; Wu, Junxiong; Tang, Chang

2016-01-01

Dense and crack-free barium titanate (BaTiO3, BTO) thin films with a thickness of less than 4 μm were prepared by using sub-micrometric scale, layer-by-layer electrohydrodynamic jet (E-jet) deposition of the suspension ink which is composed of BTO nanopowder and BTO sol. Impacts of the jet height and line-to-line pitch of the deposition on the micro-structure of BTO thin films were investigated. Results show that crack-free BTO thin films can be prepared with 4 mm jet height and 300 μm line-to-line pitch in this work. Dielectric constant of the prepared BTO thin film was recorded as high as 2940 at 1 kHz at room temperature. Meanwhile, low dissipation factor of the BTO thin film of about 8.6% at 1 kHz was also obtained. The layer-by-layer E-jet deposition technique developed in this work has been proved to be a cost-effective, flexible and easy to control approach for the preparation of high-quality solid thin film. PMID:28787860

MultiLayer solid electrolyte for lithium thin film batteries

DOEpatents

Lee, Se -Hee; Tracy, C. Edwin; Pitts, John Roland; Liu, Ping

2015-07-28

A lithium metal thin-film battery composite structure is provided that includes a combination of a thin, stable, solid electrolyte layer [18] such as Lipon, designed in use to be in contact with a lithium metal anode layer; and a rapid-deposit solid electrolyte layer [16] such as LiAlF.sub.4 in contact with the thin, stable, solid electrolyte layer [18]. Batteries made up of or containing these structures are more efficient to produce than other lithium metal batteries that use only a single solid electrolyte. They are also more resistant to stress and strain than batteries made using layers of only the stable, solid electrolyte materials. Furthermore, lithium anode batteries as disclosed herein are useful as rechargeable batteries.

Determination of the size and phase composition of silver nanoparticles in a gel film of bacterial cellulose by small-angle X-ray scattering, electron diffraction, and electron microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Volkov, V. V.; Klechkovskaya, V. V., E-mail: klechvv@ns.crys.ras.ru; Shtykova, E. V.

2009-03-15

The nanoscale structural features in a composite (gel film of Acetobacter Xylinum cellulose with adsorbed silver nanoparticles, stabilized by N-polyvinylpyrrolidone) have been investigated by small-angle X-ray scattering. The size distributions of inhomogeneities in the porous structure of the cellulose matrix and the size distributions of silver nanoparticles in the composite have been determined. It is shown that the sizes of synthesized nanoparticles correlate with the sizes of inhomogeneities in the gel film. Particles of larger size (with radii up to 100 nm) have also been found. Electron microscopy of thin cross sections of a dried composite layer showed that largemore » particles are located on the cellulose layer surface. Electron diffraction revealed a crystal structure of silver nanoparticles in the composite.« less

Tape method of forming a thin layer of doped lanthanum chromite particles and of bonding such on an electrode

DOEpatents

Richards, Von L.; Singhal, Subhash C.; Pal, Uday B.

1992-01-01

A combustible polymer film, useful for application of an interconnection on an electrode is made by: (1) providing doped LaCro.sub.3 particles; (2) dispersing doped LaCrO.sub.3 particles in a solvent, to provide a dispersion; (3) screening the dispersion to provide particles in the range of from 30 micrometers to 80 micrometers; (4) admixing a fugitive polymer with the particles; (5) casting the dispersion to provide a film; (6) drying the film; and (7) stripping the film. The film can then be applied to a porous, preheated electrode top surface, and then electrochemical vapor depositing a dense skeletal LaCrO.sub.3 structure, between and around the doped LaCrO.sub.3 particles. Additional solid oxide electrolyte and fuel electrode layers can then be added to provide a fuel cell.

Tape method of forming a thin layer of doped lanthanum chromite particles and of bonding such on an electrode

DOEpatents

Richards, V.L.; Singhal, S.C.; Pal, U.B.

1992-07-21

A combustible polymer film, useful for application of an interconnection on an electrode is made by: (1) providing doped LaCro[sub 3] particles; (2) dispersing doped LaCrO[sub 3] particles in a solvent, to provide a dispersion; (3) screening the dispersion to provide particles in the range of from 30 micrometers to 80 micrometers; (4) admixing a fugitive polymer with the particles; (5) casting the dispersion to provide a film; (6) drying the film; and (7) stripping the film. The film can then be applied to a porous, preheated electrode top surface, and then a dense skeletal LaCrO[sub 3] structure is electrochemically vapor deposited between and around the doped LaCrO[sub 3] particles. Additional solid oxide electrolyte and fuel electrode layers can then be added to provide a fuel cell. 4 figs.

The Study of Interpenetration Length between dPS Films and PS-grafted Layers

NASA Astrophysics Data System (ADS)

Lee, Hoyeon; Jo, Seongjun; Hirata, Toyoaki; Yamada, Norifumi L.; Tanaka, Keiji; Ryu, Du Yeol

In polymer thin film system, the type of interfacial interaction is a critical parameter to determining the thermal and physical properties of polymer films. Interestingly, the interfacial energy of grafted substrates with polymer chains is remarkably altered by simply controlling grafting density, which has been referred to as autophobicity. In this study, we investigated the interpenetrating interfaces between deuterated polystyrene (dPS) and grafted substrates with the same chemical identity. PS-grafted substrates were prepared using a grafting-to approach with hydroxyl end-functionalized polystyrene (PSOH) in a dry brush regime, where the brush thickness and grafting density were determined based on the chain length (or molecular weight, Mn) of PSOHs. The interpenetration lengths (ξ) at interfaces between dPS and PS-grafted layers were characterized using neutron reflectivity (NR) measurements (performed at the SOFIA beam-line at J-PARC, Japan). Academic adviser.

Developments of the Physical and Electrical Properties of NiCr and NiCrSi Single-Layer and Bi-Layer Nano-Scale Thin-Film Resistors.

PubMed

Cheng, Huan-Yi; Chen, Ying-Chung; Li, Chi-Lun; Li, Pei-Jou; Houng, Mau-Phon; Yang, Cheng-Fu

2016-02-25

In this study, commercial-grade NiCr (80 wt % Ni, 20 wt % Cr) and NiCrSi (55 wt % Ni, 40 wt % Cr, 5 wt % Si) were used as targets and the sputtering method was used to deposit NiCr and NiCrSi thin films on Al₂O₃ and Si substrates at room temperature under different deposition time. X-ray diffraction patterns showed that the NiCr and NiCrSi thin films were amorphous phase, and the field-effect scanning electronic microscope observations showed that only nano-crystalline grains were revealed on the surfaces of the NiCr and NiCrSi thin films. The log (resistivity) values of the NiCr and NiCrSi thin-film resistors decreased approximately linearly as their thicknesses increased. We found that the value of temperature coefficient of resistance (TCR value) of the NiCr thin-film resistors was positive and that of the NiCrSi thin-film resistors was negative. To investigate these thin-film resistors with a low TCR value, we designed a novel bi-layer structure to fabricate the thin-film resistors via two different stacking methods. The bi-layer structures were created by depositing NiCr for 10 min as the upper (or lower) layer and depositing NiCrSi for 10, 30, or 60 min as the lower (or upper) layer. We aim to show that the stacking method had no apparent effect on the resistivity of the NiCr-NiCrSi bi-layer thin-film resistors but had large effect on the TCR value.

Developments of the Physical and Electrical Properties of NiCr and NiCrSi Single-Layer and Bi-Layer Nano-Scale Thin-Film Resistors

PubMed Central

Cheng, Huan-Yi; Chen, Ying-Chung; Li, Chi-Lun; Li, Pei-Jou; Houng, Mau-Phon; Yang, Cheng-Fu

2016-01-01

In this study, commercial-grade NiCr (80 wt % Ni, 20 wt % Cr) and NiCrSi (55 wt % Ni, 40 wt % Cr, 5 wt % Si) were used as targets and the sputtering method was used to deposit NiCr and NiCrSi thin films on Al2O3 and Si substrates at room temperature under different deposition time. X-ray diffraction patterns showed that the NiCr and NiCrSi thin films were amorphous phase, and the field-effect scanning electronic microscope observations showed that only nano-crystalline grains were revealed on the surfaces of the NiCr and NiCrSi thin films. The log (resistivity) values of the NiCr and NiCrSi thin-film resistors decreased approximately linearly as their thicknesses increased. We found that the value of temperature coefficient of resistance (TCR value) of the NiCr thin-film resistors was positive and that of the NiCrSi thin-film resistors was negative. To investigate these thin-film resistors with a low TCR value, we designed a novel bi-layer structure to fabricate the thin-film resistors via two different stacking methods. The bi-layer structures were created by depositing NiCr for 10 min as the upper (or lower) layer and depositing NiCrSi for 10, 30, or 60 min as the lower (or upper) layer. We aim to show that the stacking method had no apparent effect on the resistivity of the NiCr-NiCrSi bi-layer thin-film resistors but had large effect on the TCR value. PMID:28344296

New chemical approach to obtain dense layer phosphate-based ionic conductor coating on negative electrode material surface: Synthesis way, outgassing and improvement of C-rate capability

NASA Astrophysics Data System (ADS)

Fleutot, Benoit; Davoisne, Carine; Gachot, Grégory; Cavalaglio, Sébastien; Grugeon, Sylvie; Viallet, Virginie

2017-04-01

Li4Ti5O12 (LTO) based batteries have severe gassing behavior during charge/discharge and storage process, due to interfacial reactions between active material and electrolyte solution. In the same time, the electronic and ionic conductivity of pristine LTO is very poor and induces the use of nanoparticles which increase the outgassing phenomena. The coating of LTO particles could be a solution. For this the LTO spinel particles are modified with ionic conductor Li3PO4 coating using a spray-drying method. For the first time a homogeneous thin dense layer phosphate based conductor is obtained without nanoparticles, as a thin film material. It is so possible to study the influence of ionic conductor deposited on the negative electrode material on performances by the controlled layer thickness. This coating was characterized by XRD, SEM, XPS and TEM. The electrochemical performance of Li3PO4 coated Li4Ti5O12 is improved at high C-rate by the surface modification (improvement of 30 mAh g-1 at 5 C-rate compared to pristine LTO for 5 nm of coating), inducing by a modification of surface energy. An optimum coating thickness was studied. This type of coating allows a significant decrease of outgassing phenomena due the conformal coating and opens the way to a great number of studies and new technologies.

Monitoring the layer-by-layer self-assembly of graphene and graphene oxide by spectroscopic ellipsometry.

PubMed

Zhou, Kai-Ge; Chang, Meng-Jie; Wang, Hang-Xing; Xie, Yu-Long; Zhang, Hao-Li

2012-01-01

Thin films of graphene oxide, graphene and copper (II) phthalocyanine dye have been successfully fabricated by electrostatic layer-by-layer (LbL) assembly approach. We present the first variable angle spectroscopic ellipsometry (VASE) investigation on these graphene-dye hybrid thin films. The thickness evaluation suggested that our LbL assembly process produces highly uniform and reproducible thin films. We demonstrate that the refractive indices of the graphene-dye thin films undergo dramatic variation in the range close to the absorption of the dyes. This investigation provides new insight to the optical properties of graphene containing thin films and shall help to establish an appropriate optical model for graphene-based hybrid materials.

Humidity-insensitive water evaporation from molecular complex fluids.

PubMed

Salmon, Jean-Baptiste; Doumenc, Frédéric; Guerrier, Béatrice

2017-09-01

We investigated theoretically water evaporation from concentrated supramolecular mixtures, such as solutions of polymers or amphiphilic molecules, using numerical resolutions of a one-dimensional model based on mass transport equations. Solvent evaporation leads to the formation of a concentrated solute layer at the drying interface, which slows down evaporation in a long-time-scale regime. In this regime, often referred to as the falling rate period, evaporation is dominated by diffusive mass transport within the solution, as already known. However, we demonstrate that, in this regime, the rate of evaporation does not also depend on the ambient humidity for many molecular complex fluids. Using analytical solutions in some limiting cases, we first demonstrate that a sharp decrease of the water chemical activity at high solute concentration leads to evaporation rates which depend weakly on the humidity, as the solute concentration at the drying interface slightly depends on the humidity. However, we also show that a strong decrease of the mutual diffusion coefficient of the solution enhances considerably this effect, leading to nearly independent evaporation rates over a wide range of humidity. The decrease of the mutual diffusion coefficient indeed induces strong concentration gradients at the drying interface, which shield the concentration profiles from humidity variations, except in a very thin region close to the drying interface.

Influences of Indium Tin Oxide Layer on the Properties of RF Magnetron-Sputtered (BaSr)TiO3 Thin Films on Indium Tin Oxide-Coated Glass Substrate

NASA Astrophysics Data System (ADS)

Kim, Tae Song; Oh, Myung Hwan; Kim, Chong Hee

1993-06-01

Nearly stoichiometric ((Ba+Sr)/Ti=1.08-1.09) and optically transparent (BaSr)TiO3 thin films were deposited on an indium tin oxide (ITO)-coated glass substrate by means of rf magnetron sputtering for their application to the insulating layer of an electroluminescent flat panel display. The influence of the ITO layer on the properties of (BaSr)TiO3 thin films deposited on the ITO-coated substrate was investigated. The ITO layer did not affect the crystallographic orientation of (BaSr)TiO3 thin film, but enhanced the grain growth. Another effect of the ITO layer on (BaSr)TiO3 thin films was the interdiffusion phenomenon, which was studied by means of secondary ion mass spectrometry (SIMS). As the substrate temperature increased, interdiffusion intensified at the interface not only between the grown film and ITO layer but also between the ITO layer and base glass substrate. The refractive index (nf) of (BaSr)TiO3 thin film deposited on a bare glass substrate was 2.138-2.286, as a function of substrate temperature.

Corrosion-resistant multilayer structures with improved reflectivity

DOEpatents

Soufli, Regina; Fernandez-Perea, Monica; Robinson, Jeff C.

2013-04-09

In one general embodiment, a thin film structure includes a substrate; a first corrosion barrier layer above the substrate; a reflective layer above the first corrosion barrier layer, wherein the reflective layer comprises at least one repeating set of sub-layers, wherein one of the sub-layers of each set of sub-layers being of a corrodible material; and a second corrosion barrier layer above the reflective layer. In another general embodiment, a system includes an optical element having a thin film structure as recited above; and an image capture or spectrometer device. In a further general embodiment, a laser according to one embodiment includes a light source and the thin film structure as recited above.

Internal hypersonic flow. [in thin shock layer

NASA Technical Reports Server (NTRS)

Lin, T. C.; Rubin, S. G.

1974-01-01

An approach for studying hypersonic internal flow with the aid of a thin-shock-layer approximation is discussed, giving attention to a comparison of thin-shock-layer results with the data obtained on the basis of the imposition theory or a finite-difference integration of the Euler equations. Relations in the case of strong interaction are considered together with questions of pressure distribution and aspects of the boundary-layer solution.

Methods for producing thin film charge selective transport layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammond, Scott Ryan; Olson, Dana C.; van Hest, Marinus Franciscus Antonius Maria

Methods for producing thin film charge selective transport layers are provided. In one embodiment, a method for forming a thin film charge selective transport layer comprises: providing a precursor solution comprising a metal containing reactive precursor material dissolved into a complexing solvent; depositing the precursor solution onto a surface of a substrate to form a film; and forming a charge selective transport layer on the substrate by annealing the film.

Al-/Ga-Doped ZnO Window Layers for Highly Efficient Cu₂ZnSn(S,Se)₄ Thin Film Solar Cells.

PubMed

Seo, Se Won; Seo, Jung Woo; Kim, Donghwan; Cheon, Ki-Beom; Lee, Doh-Kwon; Kim, Jin Young

2018-09-01

The successful use of Al-/Ga-doped ZnO (AGZO) thin films as a transparent conducting oxide (TCO) layer of a Cu2ZnSn(S,Se)4 (CZTSSe) thin film solar cell is demonstrated. The AGZO thin films were prepared by radio frequency (RF) sputtering. The structural, crystallographic, electrical, and optical properties of the AGZO thin films were systematically investigated. The photovoltaic properties of CZTSSe thin film solar cells incorporating the AGZO-based TCO layer were also reported. It has been found that the RF power and substrate temperature of the AGZO thin film are important factors determining the electrical, optical, and structural properties. The optimization process involving the RF power and the substrate temperature leads to good electrical and optical transmittance of the AGZO thin films. Finally, the CZTSSe solar cell with the AGZO TCO layer demonstrated a high conversion efficiency of 9.68%, which is higher than that of the conventional AZO counterpart by 12%.

Growth and optical property characterization of textured barium titanate thin films for photonic applications

NASA Astrophysics Data System (ADS)

Dicken, Matthew J.; Diest, Kenneth; Park, Young-Bae; Atwater, Harry A.

2007-03-01

We have investigated the growth of barium titanate thin films on bulk crystalline and amorphous substrates utilizing biaxially oriented template layers. Ion beam-assisted deposition was used to grow thin, biaxially textured, magnesium oxide template layers on amorphous and silicon substrates. Growth of highly oriented barium titanate films on these template layers was achieved by molecular beam epitaxy using a layer-by-layer growth process. Barium titanate thin films were grown in molecular oxygen and in the presence of oxygen radicals produced by a 300 W radio frequency plasma. We used X-ray and in situ reflection high-energy electron diffraction (RHEED) to analyze the structural properties and show the predominantly c-oriented grains in the films. Variable angle spectroscopic ellipsometry was used to analyze and compare the optical properties of the thin films grown with and without oxygen plasma. We have shown that optical quality barium titanate thin films, which show bulk crystal-like properties, can be grown on any substrate through the use of biaxially oriented magnesium oxide template layers.

Analysis of phytochemical profile of Terminalia arjuna bark extract with antioxidative and antimicrobial properties.

PubMed

Mandal, Shreya; Patra, Arpita; Samanta, Animesh; Roy, Suchismita; Mandal, Arpita; Mahapatra, Tapasi Das; Pradhan, Shrabani; Das, Koushik; Nandi, Dilip Kumar

2013-12-01

To investigate phytochemical screening, antimicrobial activity and qualitative thin layer chromatographic separation of flavonoid components, antioxidant activity and total flavonoid compound of Terminalia arjuna. For phytochemical screening, some common and available standard tests were done. Antimicrobial bioassay was done through agar well diffusion method. Detection of antioxidant activity and flavonoid compounds were done through thin layer chromatography. Total antioxidant activity was measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) in colorimetric method. Aluminum chloride colorimetric method was used for total flavonoid determination. Phytochemical screening showed the active compounds presence in high concentration, such as phytosterol, lactones, flavonoids, phenolic compounds and tannins and glycosides. The antimicrobial activity of extract showed that greater inhibition zone against Gram negative bacteria than Gram positive bacteria. This methanolic extract showed a promising antioxidant activity, as absorption of DPPH redicles decreased in DPPH free radical scavenging assay. Flavonoids components having antioxidant property present in the methanol extract at a level of 199.00 mg quercetin equivalent/g of dried methanol extract in colorimetric method. The Terminalia arjuna bark extract revealed the presence of bio-active constituents which are known to exhibit medicinal as well as physiological activities. Copyright © 2013 Asian Pacific Tropical Biomedical Magazine. Published by Elsevier B.V. All rights reserved.

Determination of caffeine, theobromine and theophylline in Mate beer and Mate soft drinks by high-performance thin-layer chromatography.

PubMed

Oellig, Claudia; Schunck, Jacob; Schwack, Wolfgang

2018-01-19

Mate beer and Mate soft drinks are beverages produced from the dried leaves of Ilex paraguariensis (Yerba Mate). In Yerba Mate, the xanthine derivatives caffeine, theobromine and theophylline, also known as methylxanthines, are important active components. The presented method for the determination of caffeine, theobromine and theophylline in Mate beer and Mate soft drinks by high-performance thin-layer chromatography with ultraviolet detection (HPTLC-UV) offers a fully automated and sensitive determination of the three methylxanthines. Filtration of the samples was followed by degassing, dilution with acetonitrile in the case of Mate beers for protein precipitation, and centrifugation before the extracts were analyzed by HPTLC-UV on LiChrospher silica gel plates with fluorescence indicator and acetone/toluene/chloroform (4:3:3, v/v/v) as the mobile phase. For quantitation, the absorbance was scanned at 274nm. Limits of detection and quantitation were 1 and 4ng/zone, respectively, for caffeine, theobromine and theophylline. With recoveries close to 100% and low standard deviations reliable results were guaranteed. Experimental Mate beers as well as Mate beers and Mate soft drinks from the market were analyzed for their concentrations of methylxanthines. Copyright © 2017 Elsevier B.V. All rights reserved.

Oxide-cladding aluminum nitride photonic crystal slab: Design and investigation of material dispersion and fabrication induced disorder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melo, E. G., E-mail: emerdemelo@usp.br; Alvarado, M. A.; Carreño, M. N. P.

2016-01-14

Photonic crystal slabs with a lower-index material surrounding the core layer are an attractive choice to circumvent the drawbacks in the fabrication of membranes suspended in air. In this work we propose a photonic crystal (PhC) slab structure composed of a triangular pattern of air holes in a multilayer thin film of aluminum nitride embedded in silicon dioxide layers designed for operating around 450 nm wavelengths. We show the design of an ideal structure and analyze the effects of material dispersion based on a first-order correction perturbation theory approach using dielectric functions obtained by experimental measurements of the thin film materials.more » Numerical methods were used to investigate the effects of fabrication induced disorder of typical nanofabrication processes on the bandgap size and spectral response of the proposed device. Deviation in holes radii and positions were introduced in the proposed PhC slab model with a Gaussian distribution profile. Impacts of slope in holes sidewalls that might result from the dry etching of AlN were also evaluated. The results show that for operation at the midgap frequency, slope in holes sidewalls is more critical than displacements in holes sizes and positions.« less

Effect of different coating layer on the topography and optical properties of ZnO nanostructured

NASA Astrophysics Data System (ADS)

Mohamed, R.; Mamat, M. H.; Malek, M. F.; Ismail, A. S.; Yusoff, M. M.; Asiah, M. N.; Khusaimi, Z.; Rusop, M.

2018-05-01

Magnesium (Mg) and aluminum (Al) co-doped zinc oxide (MAZO) thin films were synthesized on glass substrate by sol-gel spin coating method. MAZO thin films were prepared at different coating layers range from 1 to 9. Atomic Force Microscopy (AFM) was used to investigate the topography of the thin films. According to the AFM results, Root Means Square (RMS) of MAZO thin films was increased from 0.747 to 6.545 nm, with increase of number coating layer from 1 to 9, respectively. The results shown the variation on structural and topography properties of MAZO seed film when it's deposited at different coating layers on glass substrate. The optical properties was analyzed using UV-Vis spectroscopy. The obtained results show that the transmittance spectra was increased as thin films coating layer increases.

Thin layer model for nonlinear evolution of the Rayleigh-Taylor instability

NASA Astrophysics Data System (ADS)

Zhao, K. G.; Wang, L. F.; Xue, C.; Ye, W. H.; Wu, J. F.; Ding, Y. K.; Zhang, W. Y.

2018-03-01

On the basis of the thin layer approximation [Ott, Phys. Rev. Lett. 29, 1429 (1972)], a revised thin layer model for incompressible Rayleigh-Taylor instability has been developed to describe the deformation and nonlinear evolution of the perturbed interface. The differential equations for motion are obtained by analyzing the forces (the gravity and pressure difference) of fluid elements (i.e., Newton's second law). The positions of the perturbed interface are obtained from the numerical solution of the motion equations. For the case of vacuum on both sides of the layer, the positions of the upper and lower interfaces obtained from the revised thin layer approximation agree with that from the weakly nonlinear (WN) model of a finite-thickness fluid layer [Wang et al., Phys. Plasmas 21, 122710 (2014)]. For the case considering the fluids on both sides of the layer, the bubble-spike amplitude from the revised thin layer model agrees with that from the WN model [Wang et al., Phys. Plasmas 17, 052305 (2010)] and the expanded Layzer's theory [Goncharov, Phys. Rev. Lett. 88, 134502 (2002)] in the early nonlinear growth regime. Note that the revised thin layer model can be applied to investigate the perturbation growth at arbitrary Atwood numbers. In addition, the large deformation (the large perturbed amplitude and the arbitrary perturbed distributions) in the initial stage can also be described by the present model.

A Raman Microspectroscopy Study of Water and Trehalose in Spin-Dried Cells

PubMed Central

Abazari, Alireza; Chakraborty, Nilay; Hand, Steven; Aksan, Alptekin; Toner, Mehmet

2014-01-01

Long-term storage of desiccated nucleated mammalian cells at ambient temperature may be accomplished in a stable glassy state, which can be achieved by removal of water from the biological sample in the presence of glass-forming agents including trehalose. The stability of the glass may be compromised due to a nonuniform distribution of residual water and trehalose within and around the desiccated cells. Thus, quantification of water and trehalose contents at the single-cell level is critical for predicting the glass formation and stability for dry storage. Using Raman microspectroscopy, we estimated the trehalose and residual water contents in the microenvironment of spin-dried cells. Individual cells with or without intracellular trehalose were embedded in a solid thin layer of extracellular trehalose after spin-drying. We found strong evidence suggesting that the residual water was bound at a 2:1 water/trehalose molar ratio in both the extracellular and intracellular milieus. Other than the water associated with trehalose, we did not find any more residual water in the spin-dried sample, intra- or extracellularly. The extracellular trehalose film exhibited characteristics of an amorphous state with a glass transition temperature of ∼22°C. The intracellular milieu also dried to levels suitable for glass formation at room temperature. These findings demonstrate a method for quantification of water and trehalose in desiccated specimens using confocal Raman microspectroscopy. This approach has broad use in desiccation studies to carefully investigate the relationship of water and trehalose content and distribution with the tolerance to drying in mammalian cells. PMID:25418294

Two-dimensional models for the optical response of thin films

NASA Astrophysics Data System (ADS)

Li, Yilei; Heinz, Tony F.

2018-04-01

In this work, we present a systematic study of 2D optical models for the response of thin layers of material under excitation by normally incident light. The treatment, within the framework of classical optics, analyzes a thin film supported by a semi-infinite substrate, with both the thin layer and the substrate assumed to exhibit local, isotropic linear response. Starting from the conventional three-dimensional (3D) slab model of the system, we derive a two-dimensional (2D) sheet model for the thin film in which the optical response is described by a sheet optical conductivity. We develop criteria for the applicability of this 2D sheet model for a layer with an optical thickness far smaller than the wavelength of the light. We examine in detail atomically thin semi-metallic and semiconductor van-der-Waals layers and ultrathin metal films as representative examples. Excellent agreement of the 2D sheet model with the 3D slab model is demonstrated over a broad spectral range from the radio frequency limit to the near ultraviolet. A linearized version of system response for the 2D model is also presented for the case where the influence of the optically thin layer is sufficiently weak. Analytical expressions for the applicability and accuracy of the different optical models are derived, and the appropriateness of the linearized treatment for the materials is considered. We discuss the advantages, as well as limitations, of these models for the purpose of deducing the optical response function of the thin layer from experiment. We generalize the theory to take into account in-plane anisotropy, layered thin film structures, and more general substrates. Implications of the 2D model for the transmission of light by the thin film and for the implementation of half- and totally absorbing layers are discussed.

System-based approach for an advanced drug delivery platform

NASA Astrophysics Data System (ADS)

Kulinsky, Lawrence; Xu, Han; Tsai, Han-Kuan A.; Madou, Marc

2006-03-01

Present study is looking at the problem of integrating drug delivery microcapsule, a bio-sensor, and a control mechanism into a biomedical drug delivery system. A wide range of medical practices from cancer therapy to gastroenterological treatments can benefit from such novel bio-system. Drug release in our drug delivery system is achieved by electrochemically actuating an array of polymeric valves on a set of drug reservoirs. The valves are bi-layer structures, made in the shape of a flap hinged on one side to a valve seat, and consisting of thin films of evaporated gold and electrochemically deposited polypyrrole (PPy). These thin PPy(DBS) bi-layer flaps cover access holes of underlying chambers micromachined in a silicon substrate. Chromium and polyimide layers are applied to implement "differential adhesion" to obtain a voltage induced deflection of the bilayer away from the drug reservoir. The Cr is an adhesion-promoting layer, which is used to strongly bind the gold layer down to the substrate, whereas the gold adheres weakly to polyimide. Drug actives (dry or wet) were pre-stored in the chambers and their release is achieved upon the application of a small bias (~ 1V). Negative voltage causes cation adsorption and volume change in PPy film. This translates into the bending of the PPy/Au bi-layer actuator and release of the drug from reservoirs. This design of the drug delivery module is miniaturized to the dimensions of 200μm valve diameter. Galvanostatic and potentiostatic PPy deposition methods were compared, and potentiostatic deposition method yields film of more uniform thickness. PPy deposition experiments with various pyrrole and NaDBS concentrations were also performed. Glucose biosensor based on glucose oxidase (GOx) embedded in the PPy matrix during elechtrochemical deposition was manufactured and successfully tested. Multiple-drug pulsatile release and continuous linear release patterns can be implemented by controlling the operation of an array of valves. Varying amounts of drugs, together with more complex controlling strategies would allow creation of more complex drug delivery patterns.

HiRISE Observations of the Polar Regions of Mars

NASA Astrophysics Data System (ADS)

Herkenhoff, K. E.; Byrne, S.; Fishbaugh, K.; Russell, P.; Fortezzo, C.; McEwen, A.

2008-12-01

Digital elevation models (DEMs) derived from MRO HiRISE stereo images allow meter-scale topographic measurements in the north polar layered deposits (NPLD) and distinction of slope vs. albedo effects on apparent brightness of individual layers. HiRISE images do not show thin layers at the limit of resolution. Rather, fine layering, if it exists, appears to have been obscured by a more dust-rich mantling deposit which shows signs of eolian erosion and slumping. Stratigraphic sequences within the NPLD appear to be repeated within exposures observed by HiRISE, indicative of a record of periodic climate changes. Granular flows sourced from within the dark, basal unit are suggestive of, but do not require, the presence of water during their formation. Active mass wasting of frost and dust has been observed on steep NPLD scarps in early spring, similar to dry, loose snow avalanches on terrestrial slopes. Bright and dark streaks are seen to evolve during the northern summer, evidence for active eolian redistribution of frost and perhaps dark (non- volatile) material. Relatively dark reddish patches observed within the north polar residual cap during the summer indicate that the cap is very thin (<1 m) or more transparent in places. HiRISE images of exposures of the south polar layered deposits (SPLD) show rectilinear fractures that are continuous across several layers and whose orientation is not affected by the topography of the exposure, suggesting that they were formed before erosion of the SPLD. They appear to extend laterally and vertically through the SPLD, like a joint set. While NPLD tectonism appears limited to isolated grabens, several faults have been observed by HiRISE in the SPLD, showing structural details including reverse fault splays that merge into bedding planes and possible evidence for thrust duplication. The faults may be the result of basal sliding (decollements) ramping into thrust faults near the margin of the SPLD.

Detecting the Water-soluble Chloride Distribution of Cement Paste in a High-precision Way.

PubMed

Chang, Honglei; Mu, Song

2017-11-21

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a high-precision chloride profile. Firstly, paste specimens are molded, cured, and exposed to cyclic wet-dry conditions. Then, powder samples at different specimen depths are grinded when the exposure age is reached. Finally, the water-soluble chloride content is detected using a silver nitrate titration method, and chloride profiles are plotted. The key to improving the accuracy of the chloride distribution along the depth is to exclude the error in the powderization, which is the most critical step for testing the distribution of chloride. Based on the above concept, the grinding method in this protocol can be used to grind powder samples automatically layer by layer from the surface inward, and it should be noted that a very thin grinding thickness (less than 0.5 mm) with a minimum error less than 0.04 mm can be obtained. The chloride profile obtained by this method better reflects the chloride distribution in specimens, which helps researchers to capture the distribution features that are often overlooked. Furthermore, this method can be applied to studies in the field of cement-based materials, which require high chloride distribution accuracy.

Coastal Fog, South Peruvian Coast at Pisco

NASA Technical Reports Server (NTRS)

2002-01-01

Coastal fog commonly drapes the Peruvian coast. This image captures complex interactions between land, sea, and atmosphere along the southern Peruvian coast. When Shuttle astronauts took the image in February of 2002, the layers of coastal fog and stratus were being progressively scoured away by brisk south to southeast winds. Remnants of the cloud deck banked against the larger, obstructing headlands like Peninsula Paracas and Isla Sangayan, giving the prominent 'white comma' effect. Southerlies also produced ripples of internal gravity waves in the clouds offshore where warm, dry air aloft interacts with a thinning layer of cool, moist air near the sea surface on the outer edge of the remaining cloud bank. South of Peninsula Baracas, the small headlands channeled the clouds into streaks-local horizontal vortices caused by the headlands provided enough lift to give points of origin of the clouds in some bays. Besides the shelter of the peninsula, the Bahia de Pisco appears to be cloud-free due to a dry, offshore flow down the valley of the Rio Ica. The STS-109 crew took image STS109-730-80 in February 2002. The image is provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

Dry transfer of graphene to dielectrics and flexible substrates using polyimide as a transparent and stable intermediate layer

NASA Astrophysics Data System (ADS)

Marchena, Miriam; Wagner, Frederic; Arliguie, Therese; Zhu, Bin; Johnson, Benedict; Fernández, Manuel; Lai Chen, Tong; Chang, Theresa; Lee, Robert; Pruneri, Valerio; Mazumder, Prantik

2018-07-01

We demonstrate the direct transfer of graphene from Cu foil to rigid and flexible substrates, such as glass and PET, using as an intermediate layer a thin film of polyimide (PI) mixed with an aminosilane (3-aminopropyltrimethoxysilane) or only PI, respectively. While the dry removal of graphene by an adhesive has been previously demonstrated—being removed from graphite by scotch tape or from a Cu foil by thick epoxy (~20 µm) on Si—our work is the first step towards making a substrate ready for device fabrication using the polymer-free technique. Our approach leads to an article that is transparent, thermally stable—up to 350 °C—and free of polymer residues on the device side of the graphene, which is contrary to the case of the standard wet-transfer process using PMMA. Also, in addition to previous novelty, our technique is fast and easier by using current industrial technology—a hot press and a laminator—with Cu recycling by its mechanical peel-off; it provides high interfacial stability in aqueous media and it is not restricted to a specific material—polyimide and polyamic acids can be used. All the previous reasons demonstrate a feasible process that enables device fabrication.

Initial formation of calcite crystals in the thin prismatic layer with the periostracum of Pinctada fucata.

PubMed

Suzuki, Michio; Nakayama, Seiji; Nagasawa, Hiromichi; Kogure, Toshihiro

2013-02-01

Although the formation mechanism of calcite crystals in the prismatic layer has been studied well in many previous works, the initial state of calcite formation has not been observed in detail using electron microscopes. In this study, we report that the soft prismatic layer with transparent color (the thin prismatic layer) in the tip of the fresh shell of Pinctada fucata was picked up to observe the early calcification phase. A scanning electron microscope (SEM) image showed that the growth tip of the thin prismatic layer was covered by the periostracum, which was also where the initial formation of calcite crystals began. A cross-section containing the thin calcite crystals in the thin prismatic layer with the periostracum was made using a focused ion beam (FIB) system. In a transmission electron microscope (TEM) observation, the thin calcite crystal (thickness is about 1μm) on the periostracum was found to be a single crystal with the c-axis oriented perpendicular to the shell surface. On the other hand, many aggregated small particles consisting of bassanite crystals were observed in the periostracum suggesting the possibility that not only organic sulfate but also inorganic sulfates exist in the prismatic layer. These discoveries in the early calcification phase of the thin prismatic layer may help to clarify the mechanism of regulating the nucleation and orientation of the calcite crystal in the shell. Copyright © 2012 Elsevier Ltd. All rights reserved.

Buffer layers for high-Tc thin films on sapphire

NASA Technical Reports Server (NTRS)

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.

Layered ultra-thin coherent structures used as electrical resistors having low-temperature coefficient of resistivity

DOEpatents

Werner, T.R.; Falco, C.M.; Schuller, I.K.

1982-08-31

A thin film resistor having a controlled temperature coefficient of resistance (TCR) ranging from negative to positive degrees kelvin and having relatively high resistivity. The resistor is a multilayer superlattice crystal containing a plurality of alternating, ultra-thin layers of two different metals. TCR is varied by controlling the thickness of the individual layers. The resistor can be readily prepared by methods compatible with thin film circuitry manufacturing techniques.

Effect of ZnO buffer layer on phase transition properties of vanadium dioxide thin films

NASA Astrophysics Data System (ADS)

Zhu, Huiqun; Li, Lekang; Li, Chunbo

2016-03-01

VO2 thin films were prepared on ZnO buffer layers by DC magnetron sputtering at room temperature using vanadium target and post annealing at 400 °C. The ZnO buffer layers with different thickness deposited on glass substrates by magnetron sputtering have a high visible and near infrared optical transmittance. The electrical resistivity and the phase transition properties of the VO2/ZnO composite thin films in terms of temperature were investigated. The results showed that the resistivity variation of VO2 thin film with ZnO buffer layer deposited for 35 min was 16 KΩ-cm. The VO2/ZnO composite thin films exhibit a reversible semiconductor-metal phase transition at 48 °C.

Thin-Layer Fuel Cell for Teaching and Classroom Demonstrations

ERIC Educational Resources Information Center

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…

Optical characterizations of silver nanoprisms embedded in polymer thin film layers

NASA Astrophysics Data System (ADS)

Carlberg, Miriam; Pourcin, Florent; Margeat, Olivier; Le Rouzo, Judikael; Berginc, Gerard; Sauvage, Rose-Marie; Ackermann, Jorg; Escoubas, Ludovic

2017-10-01

The precise control of light-matter interaction has a wide range of applications and is currently driven by the use of nanoparticles (NPs) by the recent advances in nanotechnology. Taking advantage of the material, size, shape, and surrounding media dependence of the optical properties of plasmonic NPs, thin film layers with tunable optical properties are achieved. The NPs are synthesized by wet chemistry and embedded in a polyvinylpyrrolidone (PVP) polymer thin film layer. Spectrophotometer and spectroscopic ellipsometry measurements are coupled to finite-difference time domain numerical modeling to optically characterize the heterogeneous thin film layers. Silver nanoprisms of 10 to 50 nm edge size exhibit high absorption through the visible wavelength range. A simple optical model composed of a Cauchy law and a Lorentz law, accounting for the optical properties of the nonabsorbing polymer and the absorbing property of the nanoprisms, fits the spectroscopic ellipsometry measurements. Knowing the complex optical indices of heterogeneous thin film layers let us design layers of any optical properties.

Drying characteristics of pumpkin ( Cucurbita moschata) slices in convective and freeze dryer

NASA Astrophysics Data System (ADS)

Caliskan, Gulsah; Dirim, Safiye Nur

2017-06-01

This study was intended to determine the drying and rehydration kinetics of convective and freeze dried pumpkin slices (0.5 × 3.5 × 0.5 cm). A pilot scale tray drier (at 80 ± 2 °C inlet temperature, 1 m s-1 air velocity) and freeze drier (13.33 kPa absolute pressure, condenser temperature of -48 ± 2 °C) were used for the drying experiments. Drying curves were fitted to six well-known thin layer drying models. Nonlinear regression analysis was used to evaluate the parameters of the selected models by using statistical software SPSS 16.0 (SPSS Inc., USA). For the convective and freeze drying processes of pumpkin slices, the highest R2 values, and the lowest RMSE as well as χ2 values were obtained from Page model. The effective moisture diffusivity (Deff) of the convective and freeze dried pumpkin slices were obtained from the Fick's diffusion model, and they were found to be 2.233 × 10-7 and 3.040 × 10-9 m2s-1, respectively. Specific moisture extraction rate, moisture extraction rate, and specific energy consumption values were almost twice in freeze drying process. Depending on the results, moisture contents and water activity values of pumpkin slices were in acceptable limits for safe storage of products. The rehydration behaviour of [at 18 ± 2 and 100 ± 2 °C for 1:25, 1:50, 1:75, 1:100, and 1:125 solid:liquid ratios (w:w)] dried pumpkin slices was determined by Peleg's model with the highest R2. The highest total soluble solid loss of pumpkin slices was observed for the rehydration experiment which performed at 1:25 solid: liquid ratio (w:w). Rehydration ratio of freeze dried slices was found 2-3 times higher than convective dried slices.

Extracting elastic properties of an atomically thin interfacial layer by time-domain analysis of femtosecond acoustics

NASA Astrophysics Data System (ADS)

Chen, H.-Y.; Huang, Y.-R.; Shih, H.-Y.; Chen, M.-J.; Sheu, J.-K.; Sun, C.-K.

2017-11-01

Modern devices adopting denser designs and complex 3D structures have created much more interfaces than before, where atomically thin interfacial layers could form. However, fundamental information such as the elastic property of the interfacial layers is hard to measure. The elastic property of the interfacial layer is of great importance in both thermal management and nano-engineering of modern devices. Appropriate techniques to probe the elastic properties of interfacial layers as thin as only several atoms are thus critically needed. In this work, we demonstrated the feasibility of utilizing the time-resolved femtosecond acoustics technique to extract the elastic properties and mass density of a 1.85-nm-thick interfacial layer, with the aid of transmission electron microscopy. We believe that this femtosecond acoustics approach will provide a strategy to measure the absolute elastic properties of atomically thin interfacial layers.

A novel method for air drying aloe leaf slices by covering with filter papers as a shrink-proof layer.

PubMed

Kim, S A; Baek, J H; Lee, S J; Choi, S Y; Hur, W; Lee, S Y

2009-01-01

To prevent the shrinkage of aloe vera slices during air drying, a method utilizing a shrink-proof layer was developed. The sample was configured of whole leaf aloe slices, where 1 side or both sides were covered with filter papers as shrink-proof layers. After air drying by varying the air temperature and the slice thickness, the drying characteristics, as well as several quality factors of the dried aloe vera leaf slices, were analyzed. In the simulation of the drying curves, the modified Page model showed the best fitness, representing a diffusion-controlled drying mechanism. Nonetheless, there was a trace of a constant-rate drying period in the samples dried by the method. Shrinkage was greatly reduced, and the rehydration ratios increased by approximately 50%. Scanning electron microscopic analysis revealed that the surface structure of original fibrous form was well sustained. FT-IR characteristics showed that the dried samples could sustain aloe polysaccharide acetylation. Furthermore, the functional properties of the dried slices including water holding capacity, swelling, and fat absorption capability were improved, and polysaccharide retention levels increased by 20% to 30%. Therefore, we concluded that application of shrink-proof layers on aloe slices provides a novel way to overcome the shrinkage problems commonly found in air drying, thereby improving their functional properties with less cost. Practical Application: This research article demonstrates a novel air drying method using shrink-proof layers to prevent the shrinkage of aloe slices. We analyzed extensively the characteristics of shrinkage mechanism and physical properties of aloe flesh gels in this drying system. We concluded that this method can be a beneficial means to retain the functional properties of dried aloe, and a potential alternative to freeze drying, which is still costly.

Unexpected spontaneous ignition of Late Glacial sediments from the palaeolake Wukenfurche (NE Germany)

NASA Astrophysics Data System (ADS)

Dräger, Nadine; Brademann, Brian; Theuerkauf, Martin; Wulf, Sabine; Tjallingii, Rik; Słowiński, Michał; Schlaak, Norbert; Błaszkiewicz, Mirosław; Brauer, Achim

2015-04-01

A new finely laminated sediment archive has been recovered from the palaeolake Wukenfurche, NE Germany, comprising the last Glacial to Interglacial transition. The site is located within the Eberswalde ice-marginal valley and south of the terminal moraine that was formed during the Pomeranian phase of the Weichselian glaciation. Two sediment cores were obtained from the presently swampy area in July 2014. From these individual profiles a 14.7 m long continuous composite profile has been compiled by correlation of distinct marker layers. Glacial sand deposits covered by basal peat are found at the base of the cores. A visible volcanic ash layer 6 cm above the transition from basal peat into the overlaying finely laminated lake sediments corresponds most likely to the late Allerød Laacher See Tephra (LST). Preliminary counting on core photographs of the 3.5 m thick package of reddish and black alternating laminae above the LST yields a total of ca. 2500 layer couplets. Further micro-facies analyses on large-scale thin sections will be applied to test if these couplets are of annual origin (i.e. varves). Standard preparation for large-scale thin sections involves freeze-drying (for 48 hours) of 10 cm-long sediment slabs stored in aluminum boxes. Immediately after releasing the vacuum of the freeze-dryer chamber we observed an unexpected spontaneous combustion of the sediment from a particular interval of the profile. The exothermic combustion process lasted for approximately 10 to 20 minutes during which temperatures of up to 350°C have been measured with an infrared camera. Preliminary results suggest that oxidation of iron sulfides contributes to the observed reaction. To our knowledge this is the first time that such spontaneous combustion of lake sediments after freeze-drying has been observed. Details of the combustion process and sediment characteristics will be provided. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analysis -ICLEA- of the Helmholtz Association, grant number VH-VI-415.

Comparing the effectiveness of thinning and prescribed fire for modifying structure in dry coniferous forests

Treesearch

Richy J. Harrod; Nicholas A. Povak; David W. Peterson

2007-01-01

Forest thinning and prescribed fires are the main practices used by managers to address concerns over ecosystem degradation and severe wildland fire potential in dry forests of the Western United States. There is some debate, however, about treatment effectiveness in meeting management objectives as well as their ecological consequences. This study assesses the...

Determination of the Mass Absorption Coefficient in Two-Layer Ti/V and V/Ti Thin Film Systems by the X-Ray Fluorescence Method

NASA Astrophysics Data System (ADS)

Mashin, N. I.; Chernyaeva, E. A.; Tumanova, A. N.; Gafarova, L. M.

2016-03-01

A new XRF procedure for the determination of the mass absorption coefficient in thin film Ti/V and V/Ti two-layer systems has been proposed. The procedure uses easy-to-make thin-film layers of sputtered titanium and vanadium on a polymer film substrate. Correction coefficients have been calculated that take into account attenuation of primary radiation of the X-ray tube, as well as attenuation of the spectral line of the bottom layer element in the top layer.

Anisotropic membranes for gas separation

DOEpatents

Gollan, Arye Z.

1987-01-01

A gas separation membrane has a dense separating layer about 10,000 Angstroms or less thick and a porous support layer 10 to 400 microns thick that is an integral unit with gradually and continuously decreasing pore size from the base of the support layer to the surface of the thin separating layer and is made from a casting solution comprising ethyl cellulose and ethyl cellulose-based blends, typically greater than 47.5 ethoxyl content ethyl cellulose blended with compatible second polymers, such as nitrocellulose. The polymer content of the casting solution is from about 10% to about 35% by weight of the total solution with up to about 50% of this polymer weight a compatible second polymer to the ethyl cellulose in a volatile solvent such as isopropanol, methylacetate, methanol, ethanol, and acetone. Typical nonsolvents for the casting solutions include water and formamide. The casting solution is cast in air from about zero to 10 seconds to allow the volatile solvent to evaporate and then quenched in a coagulation bath, typically water, at a temperature of 7.degree.-25.degree. C. and then air dried at ambient temperature, typically 10.degree.-30.degree. C.

High Performance and Highly Reliable ZnO Thin Film Transistor Fabricated by Atomic Layer Deposition for Next Generation Displays

DTIC Science & Technology

2011-08-19

zinc oxide ( ZnO ) thin film as an active channel layer in TFT has become of great interest owing to their specific...630-0192 Japan Phone: +81-743-72-6060 Fax: +81-743-72-6069 E-mail: uraoka@ms.naist.jp Keywords: zinc oxide , thin film transistors , atomic layer...deposition Symposium topic: Transparent Semiconductors Oxides [Abstract] In this study, we fabricated TFTs using ZnO thin film as the

Pilot-scale submersed cultivation of R. microsporus var. oligosporus in thin stillage, a dry-grind corn-to-ethanol co-product

NASA Astrophysics Data System (ADS)

Erickson, Daniel Thomas

An innovative process to add value to a corn-to-ethanol co-product, Thin stillage, was studied for pilot-scale viability. A 1500L bioreactor was designed, operated, and optimized to cultivate Rhizopus microsporus var. oligosporus via submersed fermentation in Thin Stillage. The biomass was harvested and processed into a feed suitable for storage and ultimately for animal feeding trials. Characterization of the biomass and feed trials revealed that there is substantial potential as a nutrient dense feed supplement with 41.1% protein, 26.3% fat, and metabolizable energy on s dried basis. The amino acid profile is superior to that of DDGS, with most notably 1.7% Lys on dried basis. This process produces a significantly more nutrient dense product than DDGS, and could increase water-reclaimation in a dry-grind corn to ethanol plant. Industrially it would replace the energy intensive process of converting thin stillage into syrup that adds only $10-25/ton to DDG, while maintaining production of DDG. Using thin stillage as used a growth media for R. microsporus var. oligosporus, should not only lead to saving in energy costs, but also generate a high-value co-product which could lead to economic gains. Also there is still unexplored potential of enzymes, chitin, and co-culturing to further add value.

Thermal and Photochemical Reactions of NO2 on a Chromium (III) Oxide Surface

NASA Astrophysics Data System (ADS)

Nishino, N.; Finlayson-Pitts, B. J.

2011-12-01

Chromium oxide (Cr2O3) is a major component of the oxide layer on stainless steel surfaces. It is also widely used as pigment in paints and roofs and as a protective coating on various surfaces. While many studies have focused on the catalytic activity of Cr2O3 surfaces for selective catalytic reduction (SCR), less attention has been paid to its surface chemistry involving atmospherically important species such as NO2 under atmospheric conditions. In this study, we have investigated thermal and photochemical reactions of NO2 in the presence and the absence of water vapor, using a thin layer of Cr2O3 as a model for the surface of stainless steel as well as other similarly coated surfaces in the boundary layer. A 30 nm thick Cr2O3 film was deposited on a germanium attenuated total reflectance (ATR) crystal, and the changes in the surface species were monitored by Fourier Transform Infrared (FTIR) spectroscopy. Upon NO2 adsorption, nitrate (NO3-) ions appeared likely coordinated to Cr3+ ion(s). The NO3- peaks reversibly shifted when water vapor was added, suggesting that NO3- become solvated. Irradiation at 311 nm led to a decrease in NO3- ions under both dry and humid conditions. The major gas-phase species formed by the irradiation was NO under dry conditions, while NO2 was mainly formed in the presence of H2O. Possible mechanisms and the implications for heterogeneous NO2 chemistry in the boundary layer will be discussed. The results will also be compared to similar chemistry on other surfaces.

Use of manometric temperature measurements (MTM) to characterize the freeze-drying behavior of amorphous protein formulations.

PubMed

Johnson, Robert E; Oldroyd, Megan E; Ahmed, Saleem S; Gieseler, Henning; Lewis, Lavinia M

2010-06-01

The freeze-drying behavior and cake morphology of a model protein in an amorphous formulation were studied at varying protein concentrations using conservative (-25 degrees C) and aggressive (+25 degrees C) shelf temperatures at constant chamber pressure during primary drying. The two cycles were characterized by manometric temperature measurements (MTM) in a SMART freeze dryer that estimates the sublimation rate (dm/dt), product temperature at the freeze-drying front (T(p-MTM)) and product resistance (R(p)) during a run. The calculated sublimation rates (dm/dt) were 3-4 times faster in the aggressive cycle compared to the conservative cycle. For conservatively dried cakes R(p) increased with both dry layer thickness and protein concentration. For aggressively dried cakes (where freeze-drying occurs at the edge of microcollapse), R(p) also increased with protein concentration but was independent of the dry layer thickness. The sublimation rate was influenced by R(p), dry layer thickness and T(p-MTM) in the conservative cycle, but was governed mainly by T(p-MTM) in the aggressive cycle, where R(p) is independent of the dry layer thickness. The aggressively dried cakes had a more open and porous structure compared to their conservatively dried counterparts. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association

Tunable Nanoantennas for Surface Enhanced Infrared Absorption Spectroscopy by Colloidal Lithography and Post-Fabrication Etching

NASA Astrophysics Data System (ADS)

Chen, Kai; Duy Dao, Thang; Nagao, Tadaaki

2017-03-01

We fabricated large-area metallic (Al and Au) nanoantenna arrays on Si substrates using cost-effective colloidal lithography with different micrometer-sized polystyrene spheres. Variation of the sphere size leads to tunable plasmon resonances in the middle infrared (MIR) range. The enhanced near-fields allow us to detect the surface phonon polaritons in the natural SiO2 thin layers. We demonstrated further tuning capability of the resonances by employing dry etching of the Si substrates with the nanoantennas acting as the etching masks. The effective refractive index of the nanoantenna surroundings is efficiently decreased giving rise to blueshifts of the resonances. In addition, partial removal of the Si substrates elevates the nanoantennas from the high-refractive-index substrates making more enhanced near-fields accessible for molecular sensing applications as demonstrated here with surface-enhanced infrared absorption (SEIRA) spectroscopy for a thin polymer film. We also directly compared the plasmonic enhancement from the Al and Au nanoantenna arrays.

Domain matched epitaxial growth of (111) Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} thin films on (0001) Al{sub 2}O{sub 3} with ZnO buffer layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnaprasad, P. S., E-mail: pskrishnaprasu@gmail.com, E-mail: mkj@cusat.ac.in; Jayaraj, M. K., E-mail: pskrishnaprasu@gmail.com, E-mail: mkj@cusat.ac.in; Antony, Aldrin

2015-03-28

Epitaxial (111) Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} (BST) thin films have been grown by pulsed laser deposition on (0001) Al{sub 2}O{sub 3} substrate with ZnO as buffer layer. The x-ray ω-2θ, Φ-scan and reciprocal space mapping indicate epitaxial nature of BST thin films. The domain matched epitaxial growth of BST thin films over ZnO buffer layer was confirmed using Fourier filtered high resolution transmission electron microscope images of the film-buffer interface. The incorporation of ZnO buffer layer effectively suppressed the lattice mismatch and promoted domain matched epitaxial growth of BST thin films. Coplanar inter digital capacitors fabricated on epitaxial (111) BSTmore » thin films show significantly improved tunable performance over polycrystalline thin films.« less

Experimental Study of Acid Treatment Toward Characterization of Structural, Optical, and Morphological Properties of TiO2-SnO2 Composite Thin Film

NASA Astrophysics Data System (ADS)

Fajar, M. N.; Hidayat, R.; Triwikantoro; Endarko

2018-04-01

The TiO2-SnO2 thin film with single and double-layer structure has successfully synthesized on FTO (Fluorine-doped Tin Oxide) substrate using the screen printing technique. The structural, optical, and morphological properties of the film were investigated by XRD, UV-Vis, and SEM, respectively. The results showed that the single and double-layer structure of TiO2-SnO2 thin film has mixed phase with a strong formation of casseritte phase. The acid treatment effect on TiO2-SnO2 thin film decreases the peak intensity of anatase phase formation and thin film’s absorbance values. The morphological study is also revealed that the single layer TiO2-SnO2 thin film had a more porous nature and decreased particle size distribution after acid treatment, while the double-layer TiO2-SnO2 thin film Eroded due to acid treatment.

Nanopore thin film enabled optical platform for drug loading and release.

PubMed

Song, Chao; Che, Xiangchen; Que, Long

2017-08-07

In this paper, a drug loading and release device fabricated using nanopore thin film and layer-by-layer (LbL) nanoassembly is reported. The nanopore thin film is a layer of anodic aluminum oxide (AAO), consisting of honeycomb-shape nanopores. Using the LbL nanoassembly process, the drug, using gentamicin sulfate (GS) as the model, can be loaded into the nanopores and the stacked layers on the nanopore thin film surface. The drug release from the device is achieved by immersing it into flowing DI water. Both the loading and release processes can be monitored optically. The effect of the nanopore size/volume on drug loading and release has also been evaluated. Further, the neuron cells have been cultured and can grow normally on the nanopore thin film, verifying its bio-compatibility. The successful fabrication of nanopore thin film device on silicon membrane render it as a potential implantable controlled drug release device.

Surface passivation investigation on ultra-thin atomic layer deposited aluminum oxide layers for their potential application to form tunnel layer passivated contacts

NASA Astrophysics Data System (ADS)

Xin, Zheng; Ling, Zhi Peng; Nandakumar, Naomi; Kaur, Gurleen; Ke, Cangming; Liao, Baochen; Aberle, Armin G.; Stangl, Rolf

2017-08-01

The surface passivation performance of atomic layer deposited ultra-thin aluminium oxide layers with different thickness in the tunnel layer regime, i.e., ranging from one atomic cycle (∼0.13 nm) to 11 atomic cycles (∼1.5 nm) on n-type silicon wafers is studied. The effect of thickness and thermal activation on passivation performance is investigated with corona-voltage metrology to measure the interface defect density D it(E) and the total interface charge Q tot. Furthermore, the bonding configuration variation of the AlO x films under various post-deposition thermal activation conditions is analyzed by Fourier transform infrared spectroscopy. Additionally, poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) is used as capping layer on ultra-thin AlO x tunneling layers to further reduce the surface recombination current density to values as low as 42 fA/cm2. This work is a useful reference for using ultra-thin ALD AlO x layers as tunnel layers in order to form hole selective passivated contacts for silicon solar cells.

Process for protein enrichment of cassava by solid substrate fermentation in rural conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daubresse, P.; Ntibashirwa, S.; Gheysen, A.

1987-06-01

An artisanal static process for protein enrichment of cassava by solid-state fermentation, developed in laboratory and tested on pilot units in Burundi (Central Africa), provides enriched cassava containing 10.7% of dry matter protein versus 1% before fermentation. Cassava chips, processed into granules of 2-4-mm diameter, are moistened (40% water content) and steamed. After cooling to 40 degrees C, cassava is mixed with a nutritive solution containing the inoculum (Rhizopus oryzae, strain MUCL 28627) and providing the following per 100 g dry matter: 3.4 g urea, 1.5 g KH/sub 2/PO/sub 4/, O.8 g MgSO/sub 4/.7H/sub 2/O, and 22.7 g citric acid.more » For the fermentation, cassava, with circa 60% moisture content, is spread in a thin layer (2-3 cm thick) on perforated trays and slid into an aerated humidified enclosure. The incubation lasts more or less 65 hours. The production of protein enriched cassava is 3.26 kg dry matter/square m tray. The effects of the variation of the nutritive solution composition and the inoculum conservation period on the protein production are equally discussed. (Refs. 37).« less

Separation and characterization of polycyclic aromatic hydrocarbons and alkylphenols in coal derived solvents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurtubise, R.J.; Allen, T.W.; Hussain, A.

1981-03-29

Dry-column chromatography with an aluminum oxide stationary phase and a n-hexane-ether (19:1) mobile phase was used to separate polycyclic aromatic hydrocarbons (PAH) by ring size. Prior to the dry-column chromatography step, the coal derived solvents were added to an acid treated silica gel column and eluted with chloroform. This step removed pyridine-type nitrogen heterocycles. After separation of the individual ring fractions, the fractions were further separated by either thin layer chromatography (TLC) or high performance liquid chromatography (HPLC). If TLC was used, then after separation fluorescence profiles of each PAH ring fraction distributed on 30%-acetylated cellulose chromatoplates were obtained withmore » a spectrodensitometer. Measurement of fluorescence peak heights gave an approximate measure of the amount of the 3-, 4-, 5-, and 6- ring PAH. For HPLC separation, the 3- and 4- ring PAH fractions obtained from the dry-column chromatography step were separated with a ..mu..-Bondapak C/sub 18/ column and methanol:water (65:35) mobile phase. The HPLC separated PAH were characterized by chromatographic correlation factors and corrected fluorescence excitation spectra. Alkylphenols were identified in coal recycle solvent sample following separation by HPLC.« less

Fabrication and properties of ZnO/GaN heterostructure nanocolumnar thin film on Si (111) substrate

PubMed Central

2013-01-01

Zinc oxide thin films have been obtained on bare and GaN buffer layer decorated Si (111) substrates by pulsed laser deposition (PLD), respectively. GaN buffer layer was achieved by a two-step method. The structure, surface morphology, composition, and optical properties of these thin films were investigated by X-ray diffraction, field emission scanning electron microscopy, infrared absorption spectra, and photoluminiscence (PL) spectra, respectively. Scanning electron microscopy images indicate that the flower-like grains were presented on the surface of ZnO thin films grown on GaN/Si (111) substrate, while the ZnO thin films grown on Si (111) substrate show the morphology of inclination column. PL spectrum reveals that the ultraviolet emission efficiency of ZnO thin film on GaN buffer layer is high, and the defect emission of ZnO thin film derived from Zni and Vo is low. The results demonstrate that the existence of GaN buffer layer can greatly improve the ZnO thin film on the Si (111) substrate by PLD techniques. PMID:23448090

Fabrication and properties of ZnO/GaN heterostructure nanocolumnar thin film on Si (111) substrate.

PubMed

Wei, Xianqi; Zhao, Ranran; Shao, Minghui; Xu, Xijin; Huang, Jinzhao

2013-02-28

Zinc oxide thin films have been obtained on bare and GaN buffer layer decorated Si (111) substrates by pulsed laser deposition (PLD), respectively. GaN buffer layer was achieved by a two-step method. The structure, surface morphology, composition, and optical properties of these thin films were investigated by X-ray diffraction, field emission scanning electron microscopy, infrared absorption spectra, and photoluminiscence (PL) spectra, respectively. Scanning electron microscopy images indicate that the flower-like grains were presented on the surface of ZnO thin films grown on GaN/Si (111) substrate, while the ZnO thin films grown on Si (111) substrate show the morphology of inclination column. PL spectrum reveals that the ultraviolet emission efficiency of ZnO thin film on GaN buffer layer is high, and the defect emission of ZnO thin film derived from Zni and Vo is low. The results demonstrate that the existence of GaN buffer layer can greatly improve the ZnO thin film on the Si (111) substrate by PLD techniques.

Conductive layer for biaxially oriented semiconductor film growth

DOEpatents

Findikoglu, Alp T.; Matias, Vladimir

2007-10-30

A conductive layer for biaxially oriented semiconductor film growth and a thin film semiconductor structure such as, for example, a photodetector, a photovoltaic cell, or a light emitting diode (LED) that includes a crystallographically oriented semiconducting film disposed on the conductive layer. The thin film semiconductor structure includes: a substrate; a first electrode deposited on the substrate; and a semiconducting layer epitaxially deposited on the first electrode. The first electrode includes a template layer deposited on the substrate and a buffer layer epitaxially deposited on the template layer. The template layer includes a first metal nitride that is electrically conductive and has a rock salt crystal structure, and the buffer layer includes a second metal nitride that is electrically conductive. The semiconducting layer is epitaxially deposited on the buffer layer. A method of making such a thin film semiconductor structure is also described.

Method of preparing thermal insulation for high temperature microwave sintering operations

DOEpatents

Holcombe, C.E.; Dykes, N.L.; Morrow, M.S.

1996-07-16

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering. 1 fig.

Thermal insulation for high temperature microwave sintering operations and method thereof

DOEpatents

Holcombe, C.E.; Dykes, N.L.; Morrow, M.S.

1995-09-12

Superior microwave transparent thermal insulations for high temperature microwave sintering operations were prepared. One embodiment of the thermal insulation comprises granules of boron nitride coated with a very thin layer of glassy carbon made by preparing a glassy carbon precursor and blending it with boron nitride powder to form a mixture. The blended mixture is granulated to form a grit which is dried and heated to form the granules of boron nitride coated with a glassy carbon. Alternatively, grains of glassy carbon are coated with boron nitride by blending a mixture of a slurry comprising boron nitride, boric acid binder, and methyl alcohol with glassy carbon grains to form a blended mixture. The blended mixture is dried to form grains of glassy carbon coated with boron nitride. In addition, a physical mixture of boron nitride powder and glassy carbon grains has also been shown to be an excellent thermal insulation material for microwave processing and sintering. 1 fig.

Hollow fiber optics with improved durability for high-peak-power pulses of Q-switched Nd:YAG lasers.

PubMed

Matsuura, Yuji; Tsuchiuchi, Akio; Noguchi, Hiroshi; Miyagi, Mitsunobu

2007-03-10

To improve the damage threshold of hollow optical waveguides for transmitting Q-switched Nd:YAG laser pulses, we optimize the metallization processes for the inner coating of fibers. For silver-coated hollow fiber as the base, second, and third Nd:YAG lasers, drying silver films at a moderate temperature and with inert gas flow is found to be effective. By using this drying process, the resistance to high-peak-power optical pulse radiation is drastically improved for fibers fabricated with and without the sensitizing process. The maximum peak power transmitted in the fiber is greater than 20 MW. To improve the energy threshold of aluminum-coated hollow fibers for the fourth and fifth harmonics of Nd:YAG lasers, a thin silver film is added between the aluminum film and the glass substrate to increase adhesion of the aluminum coating. By using this primer layer, the power threshold improves to 3 MW for the fourth harmonics of a Q-switched Nd:YAG laser light.

Unexpected structural and magnetic depth dependence of YIG thin films

NASA Astrophysics Data System (ADS)

Cooper, J. F. K.; Kinane, C. J.; Langridge, S.; Ali, M.; Hickey, B. J.; Niizeki, T.; Uchida, K.; Saitoh, E.; Ambaye, H.; Glavic, A.

2017-09-01

We report measurements on yttrium iron garnet (YIG) thin films grown on both gadolinium gallium garnet (GGG) and yttrium aluminum garnet (YAG) substrates, with and without thin Pt top layers. We provide three principal results: the observation of an interfacial region at the Pt/YIG interface, we place a limit on the induced magnetism of the Pt layer, and confirm the existence of an interfacial layer at the GGG/YIG interface. Polarized neutron reflectometry (PNR) was used to give depth dependence of both the structure and magnetism of these structures. We find that a thin film of YIG on GGG is best described by three distinct layers: an interfacial layer near the GGG, around 5 nm thick and nonmagnetic, a magnetic "bulk" phase, and a nonmagnetic and compositionally distinct thin layer near the surface. We theorize that the bottom layer, which is independent of the film thickness, is caused by Gd diffusion. The top layer is likely to be extremely important in inverse spin Hall effect measurements, and is most likely Y2O3 or very similar. Magnetic sensitivity in the PNR to any induced moment in the Pt is increased by the existence of the Y2O3 layer; any moment is found to be less than 0.02 μB/atom .

Methods for fabricating thin film III-V compound solar cell

DOEpatents

Pan, Noren; Hillier, Glen; Vu, Duy Phach; Tatavarti, Rao; Youtsey, Christopher; McCallum, David; Martin, Genevieve

2011-08-09

The present invention utilizes epitaxial lift-off in which a sacrificial layer is included in the epitaxial growth between the substrate and a thin film III-V compound solar cell. To provide support for the thin film III-V compound solar cell in absence of the substrate, a backing layer is applied to a surface of the thin film III-V compound solar cell before it is separated from the substrate. To separate the thin film III-V compound solar cell from the substrate, the sacrificial layer is removed as part of the epitaxial lift-off. Once the substrate is separated from the thin film III-V compound solar cell, the substrate may then be reused in the formation of another thin film III-V compound solar cell.

Schottky barrier solar cell

NASA Technical Reports Server (NTRS)

Stirn, R. J.; Yeh, Y. C. M. (Inventor)

1981-01-01

A method of fabricating a Schottky barrier solar cell is described. The cell consists of a thin substrate of low cost material with at least the top surface of the substrate being electrically conductive. A thin layer of heavily doped n-type polycrystalling germanium is deposited on the substrate after a passivation layer is deposited to prevent migration of impurities into the polycrystalline germanium. The polycrystalline germanium is recrystallized to increase the crystal sizes to serve as a base layer on which a thin layer of gallium arsenide is vapor-epitaxilly grown followed by a thermally-grown oxide layer. A metal layer is deposited on the oxide layer and a grid electrode is deposited to be in electrical contact with the top surface of the metal layer.

Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

DOEpatents

Braunlich, Peter F.; Tetzlaff, Wolfgang

1989-01-01

Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phoshphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate.

Modelling the mid-infrared drying of sweet potato: kinetics, mass and heat transfer parameters, and energy consumption

NASA Astrophysics Data System (ADS)

Onwude, Daniel I.; Hashim, Norhashila; Abdan, Khalina; Janius, Rimfiel; Chen, Guangnan

2018-04-01

This study investigated the drying kinetics, mass and heat transfer characteristics of sweet potato slices (0.4-0.6 cm thickness) during drying based on mid-infrared experimental set-up (intensity of 1100-1400 W/m2). Thin layer drying models were used to evaluate the drying kinetics of sweet potato slices. Two analytical models (Fick's diffusion model, and Dincer and Dost model) were used to study the mass transfer behaviour of sweet potato slices with and without shrinkage during mid-infrared drying. The heat transfer flux between the emitter and sweet potato slices was also investigated. Results demonstrated that an increase in infrared intensity from 1100 W/m2 to 1400 W/m2 resulted in increased in average radiation heat flux by 3.4 times and a 15% reduction in the overall drying time. The two-term exponential model was found to be the best in predicting the drying kinetics of sweet potato slices during mid-infrared drying. The specific heat consumption varied from 0.91-4.82 kWh/kg. The effective moisture diffusivity with and without shrinkage using the Fick's diffusion model varied from 2.632 × 10-9 to 1.596 × 10-8 m2/s, and 1.24 × 10-8 to 2.4 × 10-8 m2/s using Dincer and Dost model, respectively. The obtained values of mass transfer coefficient, Biot number and activation energy varied from 5.99 × 10-6 to 1.17 × 10-5 m/s, 0.53 to 2.62, and 12.83 kJ/mol to 34.64 kJ/mol, respectively. The values obtained for Biot number implied the existence of simultaneous internal and external resistances. The findings further explained that mid-infrared intensity of 1100 W/m2 did not significantly affect the quality of sweet potato during drying, demonstrating a great potential of applying low intensity mid-infrared radiation in the drying of agricultural crops.

Design and Fabrication of Electrostatically Actuated Silicon Microshutters Arrays

NASA Technical Reports Server (NTRS)

Oh, L.; Li, M.; Kim, K.; Kelly, D.; Kutyrev, A.; Moseley, S.

2017-01-01

We have developed a new fabrication process to actuate microshutter arrays (MSA) electrostatically at NASA Goddard Space Flight Center. The microshutters are fabricated on silicon with thin silicon nitride membranes. A pixel size of each microshutter is 100 x 200 micrometers 2. The microshutters rotate 90 degrees on torsion bars. The selected microshutters are actuated, held, and addressed electrostatically by applying voltages on the electrodes the front and back sides of the microshutters. The atomic layer deposition (ALD) of aluminum oxide was used to insulate electrodes on the back side of walls; the insulation can withstand over 100 V. The ALD aluminum oxide is dry etched, and then the microshutters are released in vapor HF.

Layered Organization in the Coastal Ocean: 4-D Assessment of Thin Layer Structure, Dynamics and Impacts

DTIC Science & Technology

2007-09-30

For example, the differences seen between the waters off of the US Pacific Northwest and the California Bight are almost certainly a reflection of the...the Pacific Northwest were favorable for thin layer development during that study. This is even more evident in those cases where thin layers...approach during the 2005 and 2006 LOCO process study combined time series data from an array of our Ocean Response Coastal Analysis System ( ORCAS ) (Donaghay

Synthesis and Characterization of Poly (Arylene Ether Benzimidazole) Oligomers

NASA Technical Reports Server (NTRS)

Leonard, Michael J.

1995-01-01

Several poly(arylene ether benzimidazole) oligomers were prepared by the nucleophilic aromatic substitution reaction of a bisphenol benzimidazole and various alkyl-substituted aromatic bisphenols with an activated aromatic dihalide in N, N-dimethylacetarnide. Moderate to high molecular weight terpolymers were obtained in all cases, as shown by their inherent viscosities, which ranged from 0.50 to 0.87 dL g(sup -1). Glass transition temperatures (T(sub g)s) of polymer powders ranged from 267-280 C. Air-dried unoriented thin film T(sub g)s were markedly lower than those of the powders, whereas T(sub g)s of films dried in a nitrogen atmosphere were identical to those of the corresponding powders. In addition, air-dried films were dark amber and brittle, whereas nitrogen-dried films were yellow and creasable. Nitrogen-dried films showed slightly higher thin-film tensile properties than the air-dried films, as well.

Thinning and prescribed fire effects on overstory tree and snag structure in dry coniferous forests of the interior Pacific Northwest

Treesearch

Richy J. Harrod; David W. Peterson; Nicholas A. Povak; Erich Kyle Dodson

2009-01-01

Forest thinning and prescribed fires are practices used by managers to address concerns over ecosystem degradation and severe wildland fire potential in dry forests. There is some debate, however, about treatment effectiveness in meeting management objectives as well as their ecological consequences. The purpose of this study was to assess changes to forest stand...

Energy stability of droplets and dry spots in a thin film model of hanging drops

NASA Astrophysics Data System (ADS)

Cheung, Ka-Luen; Chou, Kai-Seng

2017-10-01

The 2-D thin film equation describing the evolution of hang drops is studied. All radially symmetric steady states are classified, and their energy stability is determined. It is shown that the droplet with zero contact angle is the only global energy minimizer and the dry spot with zero contact angle is a strict local energy minimizer.

Characterization of strain relaxation behavior in Si1- x Ge x epitaxial layers by dry oxidation

NASA Astrophysics Data System (ADS)

Jang, Hyunchul; Kim, Byongju; Koo, Sangmo; Park, Seran; Ko, Dae-Hong

2017-11-01

We fabricated fully strained Si0.77Ge0.23 epitaxial layers on Si substrates and investigated their strain relaxation behaviors under dry oxidation and the effect of oxidation temperatures and times. After the oxidation process, a Ge-rich layer was formed between the oxide and the remaining Si0.77Ge0.23 layer. Using reciprocal space mapping measurements, we confirmed that the strain of the Si0.77Ge0.23 layers was efficiently relaxed after oxidation, with a maximum relaxation value of 70% after oxidation at 850 °C for 120 min. The surface of Si0.77Ge0.23 layer after strain relaxation by dry oxidation was smoother than a thick Si0.77Ge0.23 layer, which achieved a similar strain relaxation value by increasing the film thickness. Additionally, N2 annealing was performed in order to compare its effect on the relaxation compared to dry oxidation and to identify relaxation mechanisms, other than the thermally driven ones, occurring during dry oxidation.

High average power scaleable thin-disk laser

DOEpatents

Beach, Raymond J.; Honea, Eric C.; Bibeau, Camille; Payne, Stephen A.; Powell, Howard; Krupke, William F.; Sutton, Steven B.

2002-01-01

Using a thin disk laser gain element with an undoped cap layer enables the scaling of lasers to extremely high average output power values. Ordinarily, the power scaling of such thin disk lasers is limited by the deleterious effects of amplified spontaneous emission. By using an undoped cap layer diffusion bonded to the thin disk, the onset of amplified spontaneous emission does not occur as readily as if no cap layer is used, and much larger transverse thin disks can be effectively used as laser gain elements. This invention can be used as a high average power laser for material processing applications as well as for weapon and air defense applications.

Use of dry-milling derived thin stillage for producing eicosapentaenoic acid (EPA) by the fungus Pythium irregulare.

PubMed

Liang, Yi; Zhao, Xuefei; Strait, Megan; Wen, Zhiyou

2012-05-01

This study was to explore the use of thin stillage, a major byproduct in dry milling corn-ethanol plants, for production of eicosapentaenoic acid (EPA) by the fungus Pythium irregulare. Thin stillage contains various compounds that were ideal for fungal growth. Thin stillage concentration and temperature played important roles in fungal growth and EPA production. When 50% thin stillage was used in a stepwise temperature shift culture process, the cell density reached 23 g/L at day 9 with EPA yield and productivity of 243 and 27 mg/L day, respectively. The fungal biomass contained 39% lipid, 28% protein, 30% carbohydrate, and 3% ash. The fungal culture also generated a nutrient-depleted liquid by removing organic compounds in the raw thin stillage. The results collectively showed a new use of thin stillage by feeding to the fungus P. irregulare for producing omega-3 fatty acids. Copyright © 2012 Elsevier Ltd. All rights reserved.

The enhancement mechanism of thin plasma layer on antenna radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Chunsheng, E-mail: wangcs@hit.edu.cn; Jiang, Binhao; Li, Xueai

A model of plasma-antenna is carried out to study the radiation enhancement mechanism of antenna covered by thin plasma layer. The results show when the radiation intensity achieves maximum, a region of equal electric field is formed due to the reflection of electric field at the interface of plasma and air. The plasma layer acted as an extension of the antenna. Furthermore, the shape of plasma layer is changed to verify the effect of plasma boundary on antenna radiation. The study shows the effect of thin plasma layer on electromagnetic field and provides a type of plasma antenna.

Improving Fire Resistance of Cotton Fabric through Layer-by-Layer Assembled Graphene Multilayer Nanocoating

NASA Astrophysics Data System (ADS)

Jang, Wonjun; Chung, Il Jun; Kim, Junwoo; Seo, Seongmin; Park, Yong Tae; Choi, Kyungwho

2018-05-01

In this study, thin films containing poly(vinyl alcohol) (PVA) and graphene nanoplatelets (GNPs), stabilized with poly(4-styrene-sulfonic acid) (PSS), were assembled by a simple and cost-effective layer-by-layer (LbL) technique in order to introduce the anti-flammability to cotton. These antiflammable layers were characterized by using UV-vis spectrometry and quartz crystal microbalance as a function of the number of bilayers deposited. Scanning electron microscopy was used to visualize the morphology of the thin film coatings on the cotton fabric. The graphene-polymer thin films introduced anti-flammable properties through thermally stable carbonaceous layers at a high temperature. The thermal stability and flame retardant property of graphene-coated cotton was demonstrated by thermogravimetric analysis, cone calorimetry, and vertical flame test. The results indicate that LbL-assembled graphene-polymer thin films can be applied largely in the field of flame retardant.

2D granular flows with the μ(I) rheology and side walls friction: A well-balanced multilayer discretization

NASA Astrophysics Data System (ADS)

Fernández-Nieto, E. D.; Garres-Díaz, J.; Mangeney, A.; Narbona-Reina, G.

2018-03-01

We present here numerical modelling of granular flows with the μ (I) rheology in confined channels. The contribution is twofold: (i) a model to approximate the Navier-Stokes equations with the μ (I) rheology through an asymptotic analysis; under the hypothesis of a one-dimensional flow, this model takes into account side walls friction; (ii) a multilayer discretization following Fernández-Nieto et al. (2016) [20]. In this new numerical scheme, we propose an appropriate treatment of the rheological terms through a hydrostatic reconstruction which allows this scheme to be well-balanced and therefore to deal with dry areas. Based on academic tests, we first evaluate the influence of the width of the channel on the normal profiles of the downslope velocity thanks to the multilayer approach that is intrinsically able to describe changes from Bagnold to S-shaped (and vice versa) velocity profiles. We also check the well-balanced property of the proposed numerical scheme. We show that approximating side walls friction using single-layer models may lead to strong errors. Secondly, we compare the numerical results with experimental data on granular collapses. We show that the proposed scheme allows us to qualitatively reproduce the deposit in the case of a rigid bed (i.e. dry area) and that the error made by replacing the dry area by a small layer of material may be large if this layer is not thin enough. The proposed model is also able to reproduce the time evolution of the free surface and of the flow/no-flow interface. In addition, it reproduces the effect of erosion for granular flows over initially static material lying on the bed. This is possible when using a variable friction coefficient μ (I) but not with a constant friction coefficient.

Programmable Electrochemical Rectifier Based on a Thin-Layer Cell.

PubMed

Park, Seungjin; Park, Jun Hui; Hwang, Seongpil; Kwak, Juhyoun

2017-06-21

A programmable electrochemical rectifier based on thin-layer electrochemistry is described here. Both the rectification ratio and the response time of the device are programmable by controlling the gap distance of the thin-layer electrochemical cell, which is easily controlled using commercially available beads. One of the electrodes was modified using a ferrocene-terminated self-assembled monolayer to offer unidirectional charge transfers via soluble redox species. The thin-layer configuration provided enhanced mass transport, which was determined by the gap thickness. The device with the smallest gap thickness (∼4 μm) showed an unprecedented, high rectification ratio (up to 160) with a fast response time in a two-terminal configuration using conventional electronics.

The effects of layering in ferroelectric Si-doped HfO{sub 2} thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lomenzo, Patrick D.; Nishida, Toshikazu, E-mail: nishida@ufl.edu; Takmeel, Qanit

2014-08-18

Atomic layer deposited Si-doped HfO{sub 2} thin films approximately 10 nm thick are deposited with various Si-dopant concentrations and distributions. The ferroelectric behavior of the HfO{sub 2} thin films are shown to be dependent on both the Si mol. % and the distribution of Si-dopants. Metal-ferroelectric-insulator-semiconductor capacitors are shown to exhibit a tunable remanent polarization through the adjustment of the Si-dopant distribution at a constant Si concentration. Inhomogeneous layering of Si-dopants within the thin films effectively lowers the remanent polarization. A pinched hysteresis loop is observed for higher Si-dopant concentrations and found to be dependent on the Si layering distribution.

NMR of thin layers using a meanderline surface coil

DOEpatents

Cowgill, Donald F.

2001-01-01

A miniature meanderline sensor coil which extends the capabilities of nuclear magnetic resonance (NMR) to provide analysis of thin planar samples and surface layer geometries. The sensor coil allows standard NMR techniques to be used to examine thin planar (or curved) layers, extending NMRs utility to many problems of modern interest. This technique can be used to examine contact layers, non-destructively depth profile into films, or image multiple layers in a 3-dimensional sense. It lends itself to high resolution NMR techniques of magic angle spinning and thus can be used to examine the bonding and electronic structure in layered materials or to observe the chemistry associated with aging coatings. Coupling this sensor coil technology with an arrangement of small magnets will produce a penetrator probe for remote in-situ chemical analysis of groundwater or contaminant sediments. Alternatively, the sensor coil can be further miniaturized to provide sub-micron depth resolution within thin films or to orthoscopically examine living tissue. This thin-layer NMR technique using a stationary meanderline coil in a series-resonant circuit has been demonstrated and it has been determined that the flat meanderline geometry has about he same detection sensitivity as a solenoidal coil, but is specifically tailored to examine planar material layers, while avoiding signals from the bulk.

Effect of processing parameters on microstructure of MoS{sub 2} ultra-thin films synthesized by chemical vapor deposition method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Yang; You, Suping; Sun, Kewei

2015-06-15

MoS{sub 2} ultra-thin layers are synthesized using a chemical vapor deposition method based on the sulfurization of molybdenum trioxide (MoO{sub 3}). The ultra-thin layers are characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy and atomic force microscope (AFM). Based on our experimental results, all the processing parameters, such as the tilt angle of substrate, applied voltage, heating time and the weight of source materials have effect on the microstructures of the layers. In this paper, the effects of such processing parameters on the crystal structures and morphologies of the as-grown layers are studied. It is found that the film obtainedmore » with the tilt angle of 0.06° is more uniform. A larger applied voltage is preferred to the growth of MoS{sub 2} thin films at a certain heating time. In order to obtain the ultra-thin layers of MoS{sub 2}, the weight of 0.003 g of source materials is preferred. Under our optimal experimental conditions, the surface of the film is smooth and composed of many uniformly distributed and aggregated particles, and the ultra-thin MoS{sub 2} atomic layers (1∼10 layers) covers an area of more than 2 mm×2 mm.« less

Friction and wear life properties of polyimide thin films

NASA Technical Reports Server (NTRS)

Fusaro, R. L.

1972-01-01

A transition in the friction coefficient and wear life properties of Pyralin polyimide (PI) thin films was found to exist at a temperature between 25 deg and 100 deg C. Above this transition, PI thin films gave long wear lives and low friction coefficients. The presence of H2O in air improved the friction and wear life properties at 25 deg C; but at 100 deg C, H2O had a detrimental effect. At 100 deg C and above, a dry argon atmosphere gave lower friction coefficients and longer wear lives than did a dry air atmosphere.

The properties of plasma-enhanced atomic layer deposition (ALD) ZnO thin films and comparison with thermal ALD

NASA Astrophysics Data System (ADS)

Kim, Doyoung; Kang, Hyemin; Kim, Jae-Min; Kim, Hyungjun

2011-02-01

Zinc oxide (ZnO) thin films were prepared by plasma-enhanced atomic layer deposition (PE-ALD) using oxygen plasma as a reactant and the properties were compared with those of thermal atomic layer deposition (TH-ALD) ZnO thin films. While hexagonal wurzite phase with preferential (0 0 2) orientation was obtained for both cases, significant differences were observed in various aspects of film properties including resistivity values between these two techniques. Photoluminescence (PL) measurements have shown that high resistivity of PE-ALD ZnO thin films is due to the oxygen interstitials at low growth temperature of 200 °C, whose amount decreases with increasing growth temperature. Thin film transistors (TFT) using TH- and PE-ALD ZnO as an active layer were also fabricated and the device properties were evaluated comparatively.

Laser readable thermoluminescent radiation dosimeters and methods for producing thereof

DOEpatents

Braunlich, P.F.; Tetzlaff, W.

1989-04-25

Thin layer thermoluminescent radiation dosimeters for use in laser readable dosimetry systems, and methods of fabricating such thin layer dosimeters are disclosed. The thin layer thermoluminescent radiation dosimeters include a thin substrate made from glass or other inorganic materials capable of withstanding high temperatures and high heating rates. A thin layer of a thermoluminescent phosphor material is heat bonded to the substrate using an inorganic binder such as glass. The dosimeters can be mounted in frames and cases for ease in handling. Methods of the invention include mixing a suitable phosphor composition and binder, both being in particulate or granular form. The mixture is then deposited onto a substrate such as by using mask printing techniques. The dosimeters are thereafter heated to fuse and bond the binder and phosphor to the substrate. 34 figs.

Fermi level de-pinning of aluminium contacts to n-type germanium using thin atomic layer deposited layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gajula, D. R., E-mail: dgajula01@qub.ac.uk; Baine, P.; Armstrong, B. M.

Fermi-level pinning of aluminium on n-type germanium (n-Ge) was reduced by insertion of a thin interfacial dielectric by atomic layer deposition. The barrier height for aluminium contacts on n-Ge was reduced from 0.7 eV to a value of 0.28 eV for a thin Al{sub 2}O{sub 3} interfacial layer (∼2.8 nm). For diodes with an Al{sub 2}O{sub 3} interfacial layer, the contact resistance started to increase for layer thicknesses above 2.8 nm. For diodes with a HfO{sub 2} interfacial layer, the barrier height was also reduced but the contact resistance increased dramatically for layer thicknesses above 1.5 nm.

Characterization and modeling of low energy ion-induced damage in III-V semiconductors

NASA Astrophysics Data System (ADS)

Chen, Ching-Hui

1997-11-01

Low energy ion-induced damage (sub-keV) created during dry etching processes can extend quite deeply into materials. A systematic study on the deep penetration of dry etch-induced damage is necessary to improve device performance and helpful in further understanding the nature of defect propagation in semiconductors. In this study, a phenomenological model of dry etching damage that includes both effects of ion channeling and defect diffusion has been developed. It underscores that in addition to ion channeling, enhanced defect diffusion also plays an important role in establishing the damage profile. Further, the enhanced diffusion of dry etch- induced damage was experimentally observed for the first time by investigating the influences of concurrent above- bandgap laser illumination and low energy Ar+ ion bombardment on the damage profiles of GaAs/AlGaAs and InP-GaAs/InP heterostructures. The results indicate that non-radiative recombination of electron and hole pairs at defect sites is responsible for the observed radiation enhanced diffusion. DLTS measurements are also employed to characterize the nature of the enhanced diffusion in n-GaAs and reveal that a major component of the ion- induced defects is associated with primary point defects. Using the better understanding of the damage propagation in dry etched materials, a thin layer of low temperature grown GaAs (~200A) was utilized to stop defect propagation during dry etching process. This approach has been successfully applied to reduce ion damage that would occur during the formation of a dry-etch gate recess of a high electron mobility transistor. Finally, some future experiments are proposed and conceptually described, which would further clarify some of the many outstanding issues in the understanding and mitigation of etch- induced damage.

Mechanisms That Generate Resource Pulses in a Fluctuating Wetland

PubMed Central

Botson, Bryan A.; Gawlik, Dale E.; Trexler, Joel C.

2016-01-01

Animals living in patchy environments may depend on resource pulses to meet the high energetic demands of breeding. We developed two primary a priori hypotheses to examine relationships between three categories of wading bird prey biomass and covariates hypothesized to affect the concentration of aquatic fauna, a pulsed resource for breeding wading bird populations during the dry season. The fish concentration hypothesis proposed that local-scale processes concentrate wet-season fish biomass into patches in the dry season, whereas the fish production hypothesis states that the amount of dry-season fish biomass reflects fish biomass production during the preceding wet season. We sampled prey in drying pools at 405 sites throughout the Florida Everglades between December and May from 2006–2010 to test these hypotheses. The models that explained variation in dry-season fish biomass included water-level recession rate, wet-season biomass, microtopography, submerged vegetation, and the interaction between wet-season biomass and recession rate. Crayfish (Procambarus spp.) biomass was positively associated with wet-season crayfish biomass, moderate water depth, dense submerged aquatic vegetation, thin flocculent layer and a short interval of time since the last dry-down. Grass shrimp (Palaemonetes paludosus) biomass increased with increasing rates of water level recession, supporting our impression that shrimp, like fish, form seasonal concentrations. Strong support for wet-season fish and crayfish biomass in the top models confirmed the importance of wet-season standing stock to concentrations of fish and crayfish the following dry season. Additionally, the importance of recession rate and microtopography showed that local scale abiotic factors transformed fish production into the high quality foraging patches on which apex predators depended. PMID:27448023

Self-assembled three-dimensional and compressible interdigitated thin-film supercapacitors and batteries

PubMed Central

Nyström, Gustav; Marais, Andrew; Karabulut, Erdem; Wågberg, Lars; Cui, Yi; Hamedi, Mahiar M.

2015-01-01

Traditional thin-film energy-storage devices consist of stacked layers of active films on two-dimensional substrates and do not exploit the third dimension. Fully three-dimensional thin-film devices would allow energy storage in bulk materials with arbitrary form factors and with mechanical properties unique to bulk materials such as compressibility. Here we show three-dimensional energy-storage devices based on layer-by-layer self-assembly of interdigitated thin films on the surface of an open-cell aerogel substrate. We demonstrate a reversibly compressible three-dimensional supercapacitor with carbon nanotube electrodes and a three-dimensional hybrid battery with a copper hexacyanoferrate ion intercalating cathode and a carbon nanotube anode. The three-dimensional supercapacitor shows stable operation over 400 cycles with a capacitance of 25 F g−1 and is fully functional even at compressions up to 75%. Our results demonstrate that layer-by-layer self-assembly inside aerogels is a rapid, precise and scalable route for building high-surface-area 3D thin-film devices. PMID:26021485

Thin film electronic devices with conductive and transparent gas and moisture permeation barriers

DOEpatents

Simpson, Lin Jay

2013-12-17

A thin film stack (100, 200) is provided for use in electronic devices such as photovoltaic devices. The stack (100, 200) may be integrated with a substrate (110) such as a light transmitting/transmissive layer. A electrical conductor layer (120, 220) is formed on a surface of the substrate (110) or device layer such as a transparent conducting (TC) material layer (120,220) with pin holes or defects (224) caused by manufacturing. The stack (100) includes a thin film (130, 230) of metal that acts as a barrier for environmental contaminants (226, 228). The metal thin film (130,230) is deposited on the conductor layer (120, 220) and formed from a self-healing metal such as a metal that forms self-terminating oxides. A permeation plug or block (236) is formed in or adjacent to the thin film (130, 230) of metal at or proximate to the pin holes (224) to block further permeation of contaminants through the pin holes (224).

Productivity correlated to photobiochemical performance of Chlorella mass cultures grown outdoors in thin-layer cascades.

PubMed

Masojídek, Jiří; Kopecký, Jiří; Giannelli, Luca; Torzillo, Giuseppe

2011-02-01

This work aims to: (1) correlate photochemical activity and productivity, (2) characterize the flow pattern of culture layers and (3) determine a range of biomass densities for high productivity of the freshwater microalga Chlorella spp., grown outdoors in thin-layer cascade units. Biomass density, irradiance inside culture, pigment content and productivity were measured in the microalgae cultures. Chlorophyll-fluorescence quenching was monitored in situ (using saturation-pulse method) to estimate photochemical activities. Photobiochemical activities and growth parameters were studied in cultures of biomass density between 1 and 47 g L(-1). Fluorescence measurements showed that diluted cultures (1-2 g DW L(-1)) experienced significant photostress due to inhibition of electron transport in the PSII complex. The highest photochemical activities were achieved in cultures of 6.5-12.5 g DW L(-1), which gave a maximum daylight productivity of up to 55 g dry biomass m(-2) day(-1). A midday depression of maximum PSII photochemical yield (F (v)/F (m)) of 20-30% compared with morning values in these cultures proved to be compatible with well-performing cultures. Lower or higher depression of F (v)/F (m) indicated low-light acclimated or photo-inhibited cultures, respectively. A hydrodynamic model of the culture demonstrated highly turbulent flow allowing rapid light/dark cycles (with frequency of 0.5 s(-1)) which possibly match the turnover of the photosynthetic apparatus. These results are important from a biotechnological point of view for optimisation of growth of outdoor microalgae mass cultures under various climatic conditions.

Fabrication of read-only type triple-layered disc

NASA Astrophysics Data System (ADS)

Yang, Huei Wen; Jeng, Tzuan Ren; Yen, Wen Hsin; Chan, Rong Po; Shin, Kuo Ding; Huang, Der Ray

2003-06-01

The approach to increase optical recording density has become very popular research subject in these years. One direct and effective method is to increase the recording layer stack number. That is to say, to add one more recording layer can get one more recording capacity. In this paper, we will propose a new method for manufacturing read only type multi-layered disc. The process is described in the following. This first recorded data layer (called L0) still follows the traditional DVD disc manufacturing process. We obtain the polycarbonate substrate by replicating from Ni stamper. Then polycarbonate substrate is sputtered thin silicon film for semi-reflection layer. As for second layer (L1) and even more layer (Ln-1) producing, one special kind of duplication (called SKD) method is proposed. The duplication (or replication) source of second or nth recorded data is not only limited from Ni stamper. Even polycarbonate or PMMA substrate has recording data are also acceptable sources. At next step, the duplication source is deposited by thin gold film. Then we apply spin coating to bond the first layer (L0) substrate and second layer (L1) duplication source by choosing suitable UV curing glue. After being emitted by UV lamp for several seconds, we can easily separate the duplication source of second layer (L1) from (L0) substrate. Then we find the thin second data layer (L1) is replicated and stacks upon the first layer. On the same way, we sputter thin AgTi layer on the thin second data layer for another semi- reflective layer. By following the above manufacture step, we can produce more layers. In our experimental, we prepare triple layered read-only type disc. The total capacity is almost 12GB for one side of disc, and 24GB for two side of disc. The read-out intensity of laser from each data layer is expected to be similar. Thus we have designed particular reflectance and transmittance for each data layer by controlling the thickness of thin silicon film. We can verify our design by checking the focusing error signal in S-curve search of optical pickup head. The signal quality for each layer can be found from the signal eye pattern and jitter. For compatibility with present drive system, the requirement of the readout signal from each layer should be same as DVD or CD specification

Insight into the epitaxial encapsulation of Pd catalysts in an oriented metalloporphyrin network thin film for tandem catalysis.

PubMed

Vohra, M Ismail; Li, De-Jing; Gu, Zhi-Gang; Zhang, Jian

2017-06-14

A palladium catalyst (Pd-Cs) encapsulated metalloporphyrin network PIZA-1 thin film with bifunctional properties has been developed through a modified epitaxial layer-by-layer encapsulation approach. Combining the oxidation activity of Pd-Cs and the acetalization activity of the Lewis acidic sites in the PIZA-1 thin film, this bifunctional catalyst of the Pd-Cs@PIZA-1 thin film exhibits a good catalytic activity in a one-pot tandem oxidation-acetalization reaction. Furthermore, the surface components can be controlled by ending the top layer with different precursors in the thin film preparation procedures. The catalytic performances of these thin films with different surface composites were studied under the same conditions, which showed different reaction conversions. The result revealed that the surface component can influence the catalytic performance of the thin films. This epitaxial encapsulation offers a good understanding of the tandem catalysis for thin film materials and provides useful guidance to develop new thin film materials with catalytic properties.

Use of a thin-layer technique in thyroid fine needle aspiration.

PubMed

Malle, Despoina; Valeri, Rosalia-Maria; Pazaitou-Panajiotou, Kalliopi; Kiziridou, Anastasia; Vainas, Iraklis; Destouni, Charicleia

2006-01-01

To investigate the efficacy of the ThinPrep Processor (Cytyc Corporation, Boxborough, Massachusetts, U.S.A) in fine needle aspiration (FNA) of thyroid gland lesions. This study included 459 thyroid FNA specimens obtained from patients who came to our endocrinology department with various thyroid disorders over 3 years. The cytologic material was prepared using both the conventional and ThinPrep method in the first 2 years (285 cases), while in the last one only the ThinPrep method was used (1 74 cases). The smears were stained using a modified Papanicolaou procedure and May-Grünwald-Giemsa stain. Immunocytochemistry was performed on thin-layer slides using specific monoclonal antibodies when needed. Thin-layer and direct smear diagnoses were compared with the final cytologic or histologic diagnoses, when available. Our cases included 279 adenomatoid nodules, 15 cases of Hashimoto thyroiditis, 45 follicular neoplasms, 14 Hürthle cell tumors, 58 papillary carcinomas and 1 5 anaplastic carcinomas. Thin-layer preparations showed a trend toward a lower proportion of inadequate specimens and a lower false negative rate. Cytomorphologic features showed some differences between the 2 methods. Colloid was less frequently observed on ThinPrep slides, while nuclear detail and micronucleoli were more easily detected with this technique. Moreover, ThinPrep appeared to be the appropriate method for the use of ancillary techniques in suspicious cases. Thin-layer cytology improves the diagnostic accuracy of thyroid FNA and offers the possibility of performing new techniques, such as immunocytochemistry, on the same sample in order to detect malignancy as well as the type and origin of thyroid gland neoplasms.

Photovoltaic sub-cell interconnects

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Hest, Marinus Franciscus Antonius Maria; Swinger Platt, Heather Anne

2017-05-09

Photovoltaic sub-cell interconnect systems and methods are provided. In one embodiment, a photovoltaic device comprises a thin film stack of layers deposited upon a substrate, wherein the thin film stack layers are subdivided into a plurality of sub-cells interconnected in series by a plurality of electrical interconnection structures; and wherein the plurality of electrical interconnection structures each comprise no more than two scribes that penetrate into the thin film stack layers.

Effect of atmospheric-pressure plasma treatment on the adhesion properties of a thin adhesive layer in a selective transfer process

NASA Astrophysics Data System (ADS)

Yoon, Min-Ah; Kim, Chan; Hur, Min; Kang, Woo Seok; Kim, Jaegu; Kim, Jae-Hyun; Lee, Hak-Joo; Kim, Kwang-Seop

2018-01-01

The adhesion between a stamp and thin film devices is crucial for their transfer on a flexible substrate. In this paper, a thin adhesive silicone layer on the stamp was treated by atmospheric pressure plasma to locally control the adhesion strength for the selective transfer. The adhesion strength of the silicone layer was significantly reduced after the plasma treatment, while its surface energy was increased. To understand the inconsistency between the adhesion strength and surface energy changes, the surface properties of the silicone layer were characterized using nanoindentation and X-ray photoelectron spectroscopy. These techniques revealed that a thin, hard, silica-like layer had formed on the surface from plasma-enhanced oxidation. This layer played an important role in decreasing the contact area and increasing the interfacial slippage, resulting in decreased adhesion. As a practical application, the transfer process was demonstrated on GaN LEDs that had been previously delaminated by a laser lift-off (LLO) process. Although the LEDs were not transferred onto the treated adhesive layer due to the reduced adhesion, the untreated adhesive layer could readily pick up the LEDs. It is expected that this simple method of controlling the adhesion of a stamp with a thin adhesive layer would enable a continuous, selective and large-scale roll-to-roll selective transfer process and thereby advance the development of flexible, stretchable and wearable electronics.

Study on the growth mechanism and optical properties of sputtered lead selenide thin films

NASA Astrophysics Data System (ADS)

Sun, Xigui; Gao, Kewei; Pang, Xiaolu; Yang, Huisheng; Volinsky, Alex A.

2015-11-01

Lead selenide thin films with different microstructure were deposited on Si (1 0 0) substrates using magnetron sputtering at 50 °C, 150 °C and 250 °C, respectively. The crystal structure of the sputtered PbSe thin films varies from amorphous crystalline to columnar grain, and then to double-layer (nano-crystalline layer and columnar grain layer) structure as the deposition temperature increases, which is due to the dominating growth mode of the thin films changes from Frank-van der Merwe (or layer-by-layer) growth mode at 50 °C to Volmer-Weber (or 3D island) growth mode at 150 °C, and then to Stranski-Krastanow (or 3D island-on-wetting-layer) growth mode at 250 °C. The growth mechanism of the sputtered PbSe thin films is mainly dominated by the surface and strain energy contributions. Moreover, the strain energy contribution is more prominent when the deposition temperature is less than 180 °C, while, the surface energy contribution is more prominent when the deposition temperature is higher than 180 °C. The absorption spectra of the sputtered PbSe thin films are in 3.1-5 μm range. Besides, the sputtered PbSe thin film prepared at 250 °C has two different optical band gaps due to its unique double-layer structure. According to the theoretical calculation results, the variation of the band gap with the deposition temperature is determined by the shift of the valence band maximum with the lattice constant.

Synthesis and characterization of Zn(O,OH)S and AgInS2 layers to be used in thin film solar cells

NASA Astrophysics Data System (ADS)

Vallejo, W.; Arredondo, C. A.; Gordillo, G.

2010-11-01

In this paper AgInS2 and Zn(O,OH)S thin films were synthesized and characterized. AgInS2 layers were grown by co-evaporation from metal precursors in a two-step process, and, Zn(O,OH)S thin films were deposited from chemical bath containing thiourea, zinc acetate, sodium citrate and ammonia. X-ray diffraction measurements indicated that AgInS2 thin films grown with chalcopyrite structure, and the as-grown Zn(O,OH)S thin films were polycrystalline. It was also found that the AgInS2 films presented p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and energy band-gap Eg of about 1.95 eV, Zn(O,OH),S thin films presented Eg of about 3.89 eV. Morphological analysis showed that under this synthesis conditions Zn(O,OH),S thin films coated uniformly the absorber layer. Additionally, the Zn(O,OH)S kinetic growth on AgInS2 layer was studied also. Finally, the results suggest that these layers possibly could be used in one-junction solar cells and/or as top cell in a tandem solar cell.

Deformation behavior of coherently strained InAs/GaAs(111)A heteroepitaxial systems: Theoretical calculations and experimental measurements

NASA Astrophysics Data System (ADS)

Zepeda-Ruiz, Luis A.; Pelzel, Rodney I.; Nosho, Brett Z.; Weinberg, W. Henry; Maroudas, Dimitrios

2001-09-01

A comprehensive, quantitative analysis is presented of the deformation behavior of coherently strained InAs/GaAs(111)A heteroepitaxial systems. The analysis combines a hierarchical theoretical approach with experimental measurements. Continuum linear elasticity theory is linked with atomic-scale calculations of structural relaxation for detailed theoretical studies of deformation in systems consisting of InAs thin films on thin GaAs(111)A substrates that are mechanically unconstrained at their bases. Molecular-beam epitaxy is used to grow very thin InAs films on both thick and thin GaAs buffer layers on epi-ready GaAs(111)A substrates. The deformation state of these samples is characterized by x-ray diffraction (XRD). The interplanar distances of thin GaAs buffer layers along the [220] and [111] crystallographic directions obtained from the corresponding XRD spectra indicate clearly that thin buffer layers deform parallel to the InAs/GaAs(111)A interfacial plane, thus aiding in the accommodation of the strain induced by lattice mismatch. The experimental measurements are in excellent agreement with the calculated lattice interplanar distances and the corresponding strain fields in the thin mechanically unconstrained substrates considered in the theoretical analysis. Therefore, this work contributes direct evidence in support of our earlier proposal that thin buffer layers in layer-by-layer semiconductor heteroepitaxy exhibit mechanical behavior similar to that of compliant substrates [see, e.g., B. Z. Nosho, L. A. Zepeda-Ruiz, R. I. Pelzel, W. H. Weinberg, and D. Maroudas, Appl. Phys. Lett. 75, 829 (1999)].

Self-assembly of dodecaphenyl POSS thin films

NASA Astrophysics Data System (ADS)

Handke, Bartosz; Klita, Łukasz; Niemiec, Wiktor

2017-12-01

The self-assembly abilities of Dodecaphenyl Polyhedral Oligomeric Silsesquioxane thin films on Si(1 0 0) surfaces were studied. Due to their thermal properties - relatively low sublimation temperature and preservation of molecular structure - cage type silsesquioxanes are ideal material for the preparation of a thin films by Physical Vapor Deposition. The Ultra-High Vacuum environment and the deposition precision of the PVD method enable the study of early stages of thin film growth and its molecular organization. X-ray Reflectivity and Atomic Force Microscopy measurements allow to pursuit size-effects in the structure of thin films with thickness ranges from less than a single molecular layer up to several tens of layers. Thermal treatment of the thin films triggered phase change: from a poorly ordered polycrystalline film into a well-ordered multilayer structure. Self-assembly of the layers is the effect of the π-stacking of phenyl rings, which force molecules to arrange in a superlattice, forming stacks of alternating organic-inorganic layers.

Effect of Al doping on performance of ZnO thin film transistors

NASA Astrophysics Data System (ADS)

Dong, Junchen; Han, Dedong; Li, Huijin; Yu, Wen; Zhang, Shendong; Zhang, Xing; Wang, Yi

2018-03-01

In this work, we investigate the Aluminum-doped Zinc Oxide (AZO) thin films and their feasibility as the active layer for thin film transistors (TFTs). A comparison on performance is made between the AZO TFTs and ZnO TFTs. The electrical properties such as saturation mobility, subthreshold swing, and on-to-off current ratio are improved when AZO is utilized as the active layer. Oxygen component of the thin film materials indicates that Al is the suppressor for oxygen defect in active layer, which improves the subthreshold swing. Moreover, based on band structure analyzation, we observe that the carrier concentration of AZO is higher than ZnO, leading to the enhancement of saturation mobility. The microstructure of the thin films convey that the AZO films exhibit much smaller grain boundaries than ZnO films, which results in the lower off-state current and higher on-to-off current ratio of AZO TFTs. The AZO thin films show huge potential to be the active layer of TFTs.

Thin film photovoltaic device with multilayer substrate

DOEpatents

Catalano, Anthony W.; Bhushan, Manjul

1984-01-01

A thin film photovoltaic device which utilizes at least one compound semiconductor layer chosen from Groups IIB and VA of the Periodic Table is formed on a multilayer substrate The substrate includes a lowermost support layer on which all of the other layers of the device are formed. Additionally, an uppermost carbide or silicon layer is adjacent to the semiconductor layer. Below the carbide or silicon layer is a metal layer of high conductivity and expansion coefficient equal to or slightly greater than that of the semiconductor layer.

Controlled placement and orientation of nanostructures

DOEpatents

Zettl, Alex K; Yuzvinsky, Thomas D; Fennimore, Adam M

2014-04-08

A method for controlled deposition and orientation of molecular sized nanoelectromechanical systems (NEMS) on substrates is disclosed. The method comprised: forming a thin layer of polymer coating on a substrate; exposing a selected portion of the thin layer of polymer to alter a selected portion of the thin layer of polymer; forming a suspension of nanostructures in a solvent, wherein the solvent suspends the nanostructures and activates the nanostructures in the solvent for deposition; and flowing a suspension of nanostructures across the layer of polymer in a flow direction; thereby: depositing a nanostructure in the suspension of nanostructures only to the selected portion of the thin layer of polymer coating on the substrate to form a deposited nanostructure oriented in the flow direction. By selectively employing portions of the method above, complex NEMS may be built of simpler NEMSs components.

Effect of inserting a hole injection layer in organic light-emitting diodes: A numerical approach

NASA Astrophysics Data System (ADS)

Lee, Hyeongi; Hwang, Youngwook; Won, Taeyoung

2015-01-01

For investigating the effect of inserting a hole injection layer (HIL), we carried out a computational study concerning organic light-emitting diodes (OLEDs) that had a thin CuPc layer as the hole injection layer. We used S-TAD (2, 2', 7, 7'-tetrakis-(N, Ndiphenylamino)-9, 9-spirobifluoren) for the hole transfer layer, S-DPVBi (4, 4'-bis (2, 2'-diphenylvinyl)-1, 1'-spirobiphenyl) for the emission layer and Alq3 (Tris (8-hyroxyquinolinato) aluminium) for the electron transfer layer. This tri-layer device was compared with four-layer devices. To this tri-layer device, we added a thin CuPc layer, which had a 5.3 eV highest occupied molecular orbital (HOMO) level and a 3.8 eV lowest unoccupied molecular orbital (LUMO) level, as a hole injection layer, and we chose this device for Device A. Also, we varied the LUMO level or the HOMO level of the thin CuPc layer. These two devices were identified as Device C and Device D, respectively. In this paper, we simulated the carrier injection, transport and recombination in these four devices. Thereby, we showed the effect of the HIL, and we demonstrated that the characteristics of these devices were improved by adding a thin layer of CuPc between the anode and the HTL.

Fabrication of ATO/Graphene Multi-layered Transparent Conducting Thin Films

NASA Astrophysics Data System (ADS)

Li, Na; Chen, Fei; Shen, Qiang; Wang, Chuanbin; Zhang, Lianmeng

2013-03-01

A novel transparent conducting oxide based on the ATO/graphene multi-layered thin films has been developed to satisfy the application of transparent conductive electrode in solar cells. The ATO thin films are prepared by pulsed laser deposition method with high quality, namely the sheet resistance of 49.5 Ω/sq and average transmittance of 81.9 %. The prepared graphene sheet is well reduced and shows atomically thin, spotty distributed appearance on the top of the ATO thin films. The XRD and optical micrographs are used to confirm the successfully preparation of the ATO/graphene multi-layered thin films. The Hall measurements and UV-Vis spectrophotometer are conducted to evaluate the sheet resistance and optical transmittance of the innovative structure. It is found that graphene can improve the electrical properties of the ATO thin films with little influence on the optical transmittance.

Deer forage in a loblolly pine plantation

Treesearch

Robert M. Blair

1967-01-01

Browse yields in a 30-year-old plantation thinned at ages 20 and 25 years were directly related to the amount of pine removed and varied from 154 lb (oven-dry) per acre under light thinning to 199 lb/acre under heavy thinning. At plantation age 35, five growing seasons after a third thinning, browse yields were inversely related to pine-thinning intensity, ranging from...

Oriented conductive oxide electrodes on SiO2/Si and glass

DOEpatents

Jia, Quanxi; Arendt, Paul N.

2001-01-01

A thin film structure is provided including a silicon substrate with a layer of silicon dioxide on a surface thereof, and a layer of cubic oxide material deposited upon the layer of silicon dioxide by ion-beam-assisted-deposition, said layer of cubic oxide material characterized as biaxially oriented. Preferably, the cubic oxide material is yttria-stabilized zirconia. Additional thin layers of biaxially oriented ruthenium oxide or lanthanum strontium cobalt oxide are deposited upon the layer of yttria-stabilized zirconia. An intermediate layer of cerium oxide is employed between the yttria-stabilized zirconia layer and the lanthanum strontium cobalt oxide layer. Also, a layer of barium strontium titanium oxide can be upon the layer of biaxially oriented ruthenium oxide or lanthanum strontium cobalt oxide. Also, a method of forming such thin film structures, including a low temperature deposition of a layer of a biaxially oriented cubic oxide material upon the silicon dioxide surface of a silicon dioxide/silicon substrate is provided.

Damped response of shells by a constrained viscoelastic layer

NASA Technical Reports Server (NTRS)

El-Raheb, M.; Wagner, P.

1986-01-01

Vibration absorbers are introduced into an asymmetric configuration of thin cylinders and tori enclosing an acoustic medium. The absorbers consist of thin axial strips bonded to the cylinder with a thin viscoelastic layer. The constrained layer dissipates the energy of relative motions between strip and cylinder. The absorber is most effective on response modes with two or more circumferential waves. The use of transfer matrices is extended to the coupled cylinder-absorber system.

Photocurrent generation in SnO2 thin film by surface charged chemisorption O ions

NASA Astrophysics Data System (ADS)

Lee, Po-Ming; Liao, Ching-Han; Lin, Chia-Hua; Liu, Cheng-Yi

2018-06-01

We report a photocurrent generation mechanism in the SnO2 thin film surface layer by the charged chemisorption O ions on the SnO2 thin film surface induced by O2-annealing. A critical build-in electric field in the SnO2 surface layer resulted from the charged O ions on SnO2 surface prolongs the lifetime and reduces the recombination probability of the photo-excited electron-hole pairs by UV-laser irradiation (266 nm) in the SnO2 surface layer, which is the key for the photocurrent generation in the SnO2 thin film surface layer. The critical lifetime of prolonged photo-excited electron-hole pair is calculated to be 8.3 ms.

Multi-oxide active layer deposition using Applied Materials Pivot array coater for high-mobility metal oxide TFT

NASA Astrophysics Data System (ADS)

Park, Hyun Chan; Scheer, Evelyn; Witting, Karin; Hanika, Markus; Bender, Marcus; Hsu, Hao Chien; Yim, Dong Kil

2015-11-01

By controlling a thin indium tin oxide (ITO), indium zinc oxide interface layer between gate insulator and indium gallium zinc oxide (IGZO), the thin-film transistor (TFT) performance can reach higher mobility as conventional IGZO as well as superior stability. For large-area display application, Applied Materials static PVD array coater (Applied Materials GmbH & Co. KG, Alzenau, Germany) using rotary targets has been developed to enable uniform thin layer deposition in display industry. Unique magnet motion parameter optimization in Pivot sputtering coater is shown to provide very uniform thin ITO layer to reach TFT performance with high mobility, not only on small scale, but also on Gen8.5 (2500 × 2200 mm glass size) production system.

Highly stable thin film transistors using multilayer channel structure

NASA Astrophysics Data System (ADS)

Nayak, Pradipta K.; Wang, Zhenwei; Anjum, D. H.; Hedhili, M. N.; Alshareef, H. N.

2015-03-01

We report highly stable gate-bias stress performance of thin film transistors (TFTs) using zinc oxide (ZnO)/hafnium oxide (HfO2) multilayer structure as the channel layer. Positive and negative gate-bias stress stability of the TFTs was measured at room temperature and at 60 °C. A tremendous improvement in gate-bias stress stability was obtained in case of the TFT with multiple layers of ZnO embedded between HfO2 layers compared to the TFT with a single layer of ZnO as the semiconductor. The ultra-thin HfO2 layers act as passivation layers, which prevent the adsorption of oxygen and water molecules in the ZnO layer and hence significantly improve the gate-bias stress stability of ZnO TFTs.

Method of manufacturing a shapeable short-resistant capacitor

DOEpatents

Taylor, Ralph S.; Myers, John D.; Baney, William J.

2013-04-02

A method that employs a novel combination of conventional fabrication techniques provides a ceramic short-resistant capacitor that is bendable and/or shapeable to provide a multiple layer capacitor that is extremely compact and amenable to desirable geometries. The method allows thinner and more flexible ceramic capacitors to be made. The method includes forming a first thin metal layer on a substrate; depositing a thin, ceramic dielectric layer over the metal layer; depositing a second thin metal layer over the dielectric layer to form a capacitor exhibiting a benign failure mode; and separating the capacitor from the substrate. The method may also include bending the resulting capacitor into a serpentine arrangement with gaps between the layers that allow venting of evaporated electrode material in the event of a benign failure.

Method and apparatus for fabricating a thin-film solar cell utilizing a hot wire chemical vapor deposition technique

DOEpatents

Wang, Qi; Iwaniczko, Eugene

2006-10-17

A thin-film solar cell is provided. The thin-film solar cell comprises an a-SiGe:H (1.6 eV) n-i-p solar cell having a deposition rate of at least ten (10) .ANG./second for the a-SiGe:H intrinsic layer by hot wire chemical vapor deposition. A method for fabricating a thin film solar cell is also provided. The method comprises depositing a n-i-p layer at a deposition rate of at least ten (10) .ANG./second for the a-SiGe:H intrinsic layer.

Ultra-high current density thin-film Si diode

DOEpatents

Wang; Qi

2008-04-22

A combination of a thin-film .mu.c-Si and a-Si:H containing diode structure characterized by an ultra-high current density that exceeds 1000 A/cm.sup.2, comprising: a substrate; a bottom metal layer disposed on the substrate; an n-layer of .mu.c-Si deposited the bottom metal layer; an i-layer of .mu.c-Si deposited on the n-layer; a buffer layer of a-Si:H deposited on the i-layer, a p-layer of .mu.c-Si deposited on the buffer layer; and a top metal layer deposited on the p-layer.

Friction and wear behavior of nitrogen-doped ZnO thin films deposited via MOCVD under dry contact

DOE PAGES

Mbamara, U. S.; Olofinjana, B.; Ajayi, O. O.; ...

2016-02-01

Most researches on doped ZnO thin films are tilted toward their applications in optoelectronics and semiconductor devices. Research on their tribological properties is still unfolding. In this work, nitrogen-doped ZnO thin films were deposited on 304 L stainless steel substrate from a combination of zinc acetate and ammonium acetate precursor by MOCVD technique. Compositional and structural studies of the films were done using Rutherford Backscattering Spectroscopy (RBS) and X-ray Diffraction (XRD). The frictional behavior of the thin film coatings was evaluated using a ball-on-flat configuration in reciprocating sliding under dry contact condition. After friction test, the flat and ball counter-facemore » surfaces were examined to assess the wear dimension and failure mechanism. In conclusion, both friction behavior and wear (in the ball counter-face) were observed to be dependent on the crystallinity and thickness of the thin film coatings.« less

Efficacy of a Fatty Acids Dietary Supplement in a Polyethylene Glycol-Induced Mouse Model of Retinal Degeneration

PubMed Central

Locri, Filippo; Lardner, Emma; Kvanta, Anders; Rusciano, Dario; Bagnoli, Paola

2017-01-01

Current knowledge of the benefits of nutrition supplements for eye pathologies is based largely on the use of appropriate animal models, together with defined dietary supplementation. Here, C57BL6 mice were subretinally injected with polyethylene glycol (PEG)-400, an established model of retinal degeneration with a dry age-related macular degeneration (AMD)-like phenotype, an eye pathology that lacks treatment. In response to PEG-400, markers of the complement system, angiogenesis, inflammation, gliosis, and macrophage infiltration were upregulated in both retinas and retinal pigment epithelium (RPE)/choroids, whereas dietary supplementation with a mixture based on fatty acids counteracted their upregulation. Major effects include a reduction of inflammation, in both retinas and RPE/choroids, and an inhibition of macrophage infiltration in the choroid, yet not in the retina, suggesting a targeted action through the choroidal vasculature. Histological analysis revealed a thinning of the outer nuclear layer (ONL), together with dysregulation of the epithelium layer in response to PEG-400. In addition, immunohistofluorescence demonstrated Müller cell gliosis and macrophage infiltration into subretinal tissues supporting the molecular findings. Reduced ONL thickness, gliosis, and macrophage infiltration were counteracted by the diet supplement. The present data suggest that fatty acids may represent a useful form of diet supplementation to prevent or limit the progression of dry AMD. PMID:28961167

Synthesis of high-performance Li2FeSiO4/C composite powder by spray-freezing/freeze-drying a solution with two carbon sources

NASA Astrophysics Data System (ADS)

Fujita, Yukiko; Iwase, Hiroaki; Shida, Kenji; Liao, Jinsun; Fukui, Takehisa; Matsuda, Motohide

2017-09-01

Li2FeSiO4 is a promising cathode active material for lithium-ion batteries due to its high theoretical capacity. Spray-freezing/freeze-drying, a practical process reported for the synthesis of various ceramic powders, is applied to the synthesis of Li2FeSiO4/C composite powders and high-performance Li2FeSiO4/C composite powders are successfully synthesized by using starting solutions containing both Indian ink and glucose as carbon sources followed by heating. The synthesized composite powders have a unique structure, composed of Li2FeSiO4 nanoparticles coated with a thin carbon layer formed by the carbonization of glucose and carbon nanoparticles from Indian ink. The carbon layer enhances the electrochemical reactivity of the Li2FeSiO4, and the carbon nanoparticles play a role in the formation of electron-conducting paths in the cathode. The composite powders deliver an initial discharge capacity of 195 and 137 mAh g-1 at 0.1 C and 1 C, respectively, without further addition of conductive additive. The discharge capacity at 1 C is 72 mAh g-1 after the 100th cycle, corresponding to approximately 75% of the capacity at the 2nd cycle.

Electron transport in ultra-thin films and ballistic electron emission microscopy

NASA Astrophysics Data System (ADS)

Claveau, Y.; Di Matteo, S.; de Andres, P. L.; Flores, F.

2017-03-01

We have developed a calculation scheme for the elastic electron current in ultra-thin epitaxial heterostructures. Our model uses a Keldysh’s non-equilibrium Green’s function formalism and a layer-by-layer construction of the epitaxial film. Such an approach is appropriate to describe the current in a ballistic electron emission microscope (BEEM) where the metal base layer is ultra-thin and generalizes a previous one based on a decimation technique appropriated for thick slabs. This formalism allows a full quantum mechanical description of the transmission across the epitaxial heterostructure interface, including multiple scattering via the Dyson equation, which is deemed a crucial ingredient to describe interfaces of ultra-thin layers properly in the future. We introduce a theoretical formulation needed for ultra-thin layers and we compare with results obtained for thick Au(1 1 1) metal layers. An interesting effect takes place for a width of about ten layers: a BEEM current can propagate via the center of the reciprocal space (\\overlineΓ ) along the Au(1 1 1) direction. We associate this current to a coherent interference finite-width effect that cannot be found using a decimation technique. Finally, we have tested the validity of the handy semiclassical formalism to describe the BEEM current.

Lidar observation of transition of cirrus clouds over a tropical station Gadanki (13.45° N, 79.18° E): case studies

NASA Astrophysics Data System (ADS)

Srinivasan, M. A.; Rao, C. Dhananjaya; Krishnaiah, M.

2016-05-01

The present study describes Mie lidar observations of the cirrus cloud passage showing transition between double thin layers into single thick and single thick layer into double thin layers of cirrus over Gadanki region. During Case1: 17 January 2007, Case4: 12 June 2007, Case5: 14 July 2007 and Case6: 24 July 2007 the transition is found to from two thin cirrus layers into single geometrically thick layer. Case2: 14 May 2007 and Case3: 15 May 2007, the transition is found to from single geometrically thick layer into two thin cirrus layers. Linear Depolarization Ratio (LDR) and Back Scatter Ration (BSR) are found to show similar variation with strong peaks during transition; both LDR and Cloud Optical Depth (COD) is found to show similar variation except during transition with strong peaks in COD which is not clearly found from LDR for the all cases. There is a significant weakening of zonal and meridional winds during Case1 which might be due to the transition from multiple to single thick cirrus indicating potential capability of thick cirrus in modulating the wind fields. There exists strong upward wind dominance contributed to significant ascent in cloud-base altitude thereby causing transition of multiple thin layers into single thick cirrus.

Patterning layer-by-layer self-assembled multilayer by lithography and its applications to thin film devices

NASA Astrophysics Data System (ADS)

Hua, Feng

Nanoparticles are exciting materials because they exhibit unique electronic, catalytic, and optical properties. As a novel and promising nanobuilding block, it attracts considerable research efforts in its integration into a wide variety of thin film devices. Nanoparticles were adsorbed onto the substrate with layer-by-layer self-assembly which becomes of great interest due to its suitability in colloid particle assembly. Without extremely high temperatures and sophisticated equipment, molecularly organized films in an exactly pre-designed order can grow on almost all the substrates in nature. Two approaches generating spatially separated patterns comprised of nanoparticles are demonstrated, as well as two approaches patterning more than one type of nonoparticle on a silicon wafer. The structure of the thin film patterned by these approaches are analyzed and considered suitable to the thin film device. Finally, the combination of lithography and layer-by-layer (lbl) self-assembly is utilized to realize the microelectronic device with functional nonoparticles. The lbl self-assembly is the way to coat the nonoparticles and the lighography to pattern them. Based on the coating and patterning technique, a MOS-capacitor, a MOS field-effect-transistor and magnetic thin film cantilever are fabricated.

Method for collecting spores from a mold

DOEpatents

Au, Frederick H. F.; Beckert, Werner F.

1977-01-01

A technique and apparatus used therewith for determining the uptake of plutonium and other contaminants by soil microorganisms which, in turn, gives a measure of the plutonium and/or other contaminants available to the biosphere at that particular time. A measured quantity of uncontaminated spores of a selected mold is added to a moistened sample of the soil to be tested. The mixture is allowed to sit a predetermined number of days under specified temperature conditions. An agar layer is then applied to the top of the sample. After three or more days, when spores of the mold growing in the sample have formed, the spores are collected by a miniature vacuum collection apparatus operated under preselected vacuum conditions, which collect only the spores with essentially no contamination by mycelial fragments or culture medium. After collection, the fungal spores are dried and analyzed for the plutonium and/or other contaminants. The apparatus is also suitable for collection of pollen, small insects, dust and other small particles, material from thin-layer chromatography plates, etc.

System for sampling and monitoring microscopic organisms and substances

DOEpatents

Au, Frederick H. F.; Beckert, Werner F.

1976-01-01

A technique and apparatus used therewith for determining the uptake of plutonium and other contaminants by soil microorganisms which, in turn, gives a measure of the plutonium and/or other contaminants available to the biosphere at that particular time. A measured quantity of uncontaminated spores of a selected mold is added to a moistened sample of the soil to be tested. The mixture is allowed to sit a predetermined number of days under specified temperature conditions. An agar layer is then applied to the top of the sample. After three or more days, when spores of the mold growing in the sample have formed, the spores are collected by a miniature vacuum collection apparatus operated under preselected vacuum conditions, which collect only the spores with essentially no contamination by mycelial fragments or culture medium. After collection, the fungal spores are dried and analyzed for the plutonium and/or other contaminants. The apparatus is also suitable for collection of pollen, small insects, dust and other small particles, material from thin-layer chromatography plates, etc.

Sol-gel derived (La 0.8M 0.2)CrO 3 (M dbnd Ca, Sr) coating layer on stainless-steel substrate for use as a separator in intermediate-temperature solid oxide fuel cell

NASA Astrophysics Data System (ADS)

A Lee, E.; Lee, S.; Hwang, H. J.; Moon, J.-W.

A ceramic coating technique is applied to reduce the voltage drop caused by oxidation of the metallic separator (SUS444) in intermediate-temperature (IT) solid oxide fuel cell (SOFCs) systems. Precursor solutions for (La, Ca)CrO 3 (LCC) and (La, Sr)CrO 3 (LSC) coatings are prepared by adding nitric acid and ethylene glycol into an aqueous solution of lanthanum, strontium (or calcium) and chromium nitrates. Dried LCC and LSC gel films are heat-treated at 400-800 °C after dip-coating on the SUS444 substrate. XRD and Fourier-transform infrared (FT-IR) analysis is used to examine the crystallization behaviour and chemical structure of the precursor solution. The oxidation behaviour of the coated SUS444 substrate is compared with an uncoated SUS444 substrate. The oxidation of the SUS444 is inhibited by the LCC and LSC thin film layers.

Slantwise convection on fluid planets: Interpreting convective adjustment from Juno observations

NASA Astrophysics Data System (ADS)

O'Neill, M. E.; Kaspi, Y.; Galanti, E.

2016-12-01

NASA's Juno mission provides unprecedented microwave measurements that pierce Jupiter's weather layer and image the transition to an adiabatic fluid below. This region is expected to be highly turbulent and complex, but to date most models use the moist-to-dry transition as a simple boundary. We present simple theoretical arguments and GCM results to argue that columnar convection is important even in the relatively thin boundary layer, particularly in the equatorial region. We first demonstrate how surface cooling can lead to very horizontal parcel paths, using a simple parcel model. Next we show the impact of this horizontal motion on angular momentum flux in a high-resolution Jovian model. The GCM is a state-of-the-art modification of the MITgcm, with deep geometry, compressibility and interactive two-stream radiation. We show that slantwise convection primarily mixes fluid along columnar surfaces of angular momentum, and discuss the impacts this should have on lapse rate interpretation of both the Galileo probe sounding and the Juno microwave observations.

A case of rhinolithiasis in botswana: a mineralogical, microscopic and chemical study.

PubMed

Vink, Bernard W; van Hasselt, Piet; Wormald, Richard

2002-12-01

A case of rhinolithiasis in Southeast Botswana was treated and after removal in hospital, the rhinolith was subjected to macroscopic and microscopic examination, X-ray diffraction analysis, electron microscope analysis and partial botanical analysis. The rhinolith consists of a strongly elliptical core of calcium stearate (C36H70CaO4.H2O), surrounded by approximately 30 elongated concentric growth rings, consisting of sodium-containing whitlockite (Ca18Mg2(Na,H)(PO4)14). The different layers have various degrees of porosity and red staining, probably due to traces of amorphous iron oxide. The origin of the rhinolith started with a piece of plant material, lodged in the nose, which was replaced by calcium stearate, leaving some remnants of resistant epidermal plant tissue. During subsequent years, thin layers of whitlockite were deposited periodically around the core with the reddish brown bands representing deposition during the dry season when atmospheric dust rich in amorphous iron oxide is at its highest in Botswana.

Bioinspired assembly of surface-roughened nanoplatelets.

PubMed

Lin, Tzung-Hua; Huang, Wei-Han; Jun, In-Kook; Jiang, Peng

2010-04-15

Here we report a novel electrophoretic deposition technology for assembling surface-roughened inorganic nanoplatelets into ordered multilayers that mimic the brick-and-mortar nanostructure found in the nacreous layer of mollusk shells. A thin layer of sol-gel silica is coated on smooth gibbsite nanoplatelets in order to increase the surface roughness to mimic the asperity of aragonite platelets found in nacres. To avoid the severe cracking caused by the shrinkage of sol-gel silica during drying, polyelectrolyte polyethyleneimine is used to reverse the surface charge of silica-coated-gibbsite nanoplatelets and increase the adherence and strength of the electrodeposited films. Polymer nanocomposites can then be made by infiltrating the interstitials of the aligned nanoplatelet multilayers with photocurable monomer followed by photopolymerization. The resulting self-standing films are highly transparent and exhibit nearly three times higher tensile strength and one-order-of-magnitude higher toughness than those of pure polymer. The measured tensile strength agrees with that predicted by a simple shear lag model. Published by Elsevier Inc.

Organic electronic devices with multiple solution-processed layers

DOEpatents

Forrest, Stephen R.; Lassiter, Brian E.; Zimmerman, Jeramy D.

2015-08-04

A method of fabricating a tandem organic photosensitive device involves depositing a first layer of an organic electron donor type material film by solution-processing of the organic electron donor type material dissolved in a first solvent; depositing a first layer of an organic electron acceptor type material over the first layer of the organic electron donor type material film by a dry deposition process; depositing a conductive layer over the interim stack by a dry deposition process; depositing a second layer of the organic electron donor type material over the conductive layer by solution-processing of the organic electron donor type material dissolved in a second solvent, wherein the organic electron acceptor type material and the conductive layer are insoluble in the second solvent; depositing a second layer of an organic electron acceptor type material over the second layer of the organic electron donor type material film by a dry deposition process, resulting in a stack.

Thin and thick layers of resin-based sealer cement bonded to root dentine compared: Adhesive behaviour.

PubMed

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 < 0.05. The thick 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. © 2015 Australian Society of Endodontology.

Method of Fabricating Schottky Barrier solar cell

NASA Technical Reports Server (NTRS)

Stirn, R. J.; Yeh, Y. C. M. (Inventor)

1982-01-01

On a thin substrate of low cost material with at least the top surface of the substrate being electrically conductive is deposited a thin layer of heavily doped n-type polycrystalline germanium, with crystalline sizes in the submicron range. A passivation layer may be deposited on the substrate to prevent migration of impurities into the polycrystalline germanium. The polycrystalline germanium is recrystallized to increase the crystal sizes in the germanium layer to not less than 5 micros to serve as a base layer on which a thin layer of gallium arsenide is vapor epitaxially grown to a selected thickness. A thermally-grown oxide layer of a thickness of several tens of angstroms is formed on the gallium arsenide layer. A metal layer, of not more about 100 angstroms thick, is deposited on the oxide layer, and a grid electrode is deposited to be in electrical contact with the top surface of the metal layer. An antireflection coating may be deposited on the exposed top surface of the metal layer.

Characterization of aluminum selenide bi-layer thin film

NASA Astrophysics Data System (ADS)

Boolchandani, Sarita; Soni, Gyanesh; Srivastava, Subodh; Vijay, Y. K.

2018-05-01

The Aluminum Selenide (AlSe) bi-layer thin films were grown on glass substrate using thermal evaporation method under high vacuum condition. The morphological characterization was done using SEM. Electrical measurement with temperature variation shows that thin films exhibit the semiconductor nature. The optical properties of prepared thin films have also been characterized by UV-VIS spectroscopy measurements. The band gap of composite thin films has been calculated by Tauc's relation at different temperature ranging 35°C-100°C.

Dust input in the formation of rock varnish from the Dry Valleys (Antarctica)

NASA Astrophysics Data System (ADS)

Zerboni, A.; Guglielmin, M.

2017-12-01

Rock varnish is a glossy, yellowish to dark brown coating that covers geomorphically stable, aerially exposed rock surfaces and landforms in warm and cold arid lands. In warm deserts, rock varnish consists of clay minerals, Mn-Fe oxides/hydroxides, and Si+alkalis dust; it occasionally containis sulphates, phosphates, and organic remains. In Antarctica, rock varnish developed on a variety of bedrocks and has been described being mostly formed of Si, Al, Fe, and sulphates, suggesting a double process in its formation, including biomineralization alternated to dust accretion. We investigated rock coatings developed on sandstones outcropping in the Dry Valleys of Antarctica and most of the samples highlithed an extremely complex varnish structure, alternating tihn layer of different chemical compostion. Optical microscope evidenced the occurrence of highly birefringent minerals, occasionally thinly laminated and consisitng of Si and Al-rich minerals (clays). These are interlayered by few micron-thick dark lenses and continous layers. The latter are well evident under the scanning electron microscope and chemical analysis confirmed that they consist of different kinds of sulphates; jarosite is the most represented species, but gypsum crystals were also found. Fe-rich hypocoatings and intergranula crusts were also detected, sometimes preserving the shape of the hyphae they have replaced. Moreover, small weathering pits on sandstone surface display the occurrence of an amorphous, dark Mn/Fe-rich rock varnish. The formation of rock varnish in the Dry Valleys is a complex process, which required the accretion of airborne dust of variable composition and subsequent recrystallization of some constituent, possibly promoted by microorganisms. In particualr, the formation of sulphates seems to preserve the memory of S-rich dust produced by volcanic eruptions. On the contrary, the formation of Mn-rich varnish should be in relation with the occurrence of higher environmental humidity within weathering pits. Rock varnish in the Dry Valleys represents a potential tool to reconstruct past water availability and changes in the aeolian fallout.

Accumulation and Distribution of Dry Matter and Nutrients in Aigeiros Poplar Plantations

Treesearch

G. L. Switzer; L. E. Nelson; James B. Baker

1976-01-01

Patterns of accumulation of dry matter and nutrients through 20 years in Aigeiros poplar plantations are strongly influenced by mode of plantation culture. Accumulation of both dry matter and nutrients in closely spaced thinned plantations is linear through age 12 to 14, after which accumulation declines and then stabilizes. In contrast, dry matter and nutrient...

[Effects of nitrogen application rate on light interception and dry matter distribution at diffe-rent layers in wheat canopy under supplemental irrigation based on measuring soil moisture.

PubMed

Zheng, Xue Jiao; Yu, Zhen Wen; Zhang, Yong Li; Shi, Yu

2018-02-01

With the large-spike wheat cultivar Shannong 23 as test material,a field experiment was conducted by increasing the relative soil moisture content to 70% and 65% at jointing and anthesis stages. Four nitrogen levels,0 (N 0 ), 180 (N 1 ), 240 (N 2 ) and 300 kg·hm -2 (N 3 ), were designed to examine the effects of nitrogen application rates on the interception of photosynthetic active radiation (PAR) and dry matter distribution of wheat at different canopy layers. The results showed that the total stem number of wheat population at anthesis stage, the leaf area index at 10, 20 and 30 days after anthesis, PAR capture ratio at upper and middle layers and total PAR capture ratio in wheat canopy on day 20 after anthesis of treatment N 2 were significantly higher than those in the treatments of both N 0 and N 1 . Those indexes showed no significant increase when the application rate increased to 300 kg·hm -2 (N 3 ). The vegetative organ dry matter accumulation of all layers at maturity stage of treatment N 2 were significantly higher than N 0 and N 1 . Compared with treatment N 0 and N 1 , N 2 increased the grain and total dry matter accumulation by 36.7% and 35.4%, 9.5% and 10.2%, respectively, but had no significant difference with treatment N 3 . The vegetative organ dry matter accumulation at all layers, grain and total dry matter accumulation were significantly and positively correlated with PAR capture ratio at upper and middle layers, and had no significant correlation with that at lower layer. The vegetative organ dry matter accumulation at all layers was significantly and positively correlated with grain dry matter accumulation. The application rate at 240 kg·hm -2 (N 2 ) would be the optimum treatment under the present experimental condition.

Piezoresistivity of mechanically drawn single-walled carbon nanotube (SWCNT) thin films-: mechanism and optimizing principle

NASA Astrophysics Data System (ADS)

Obitayo, Waris

The individual carbon nanotube (CNT) based strain sensors have been found to have excellent piezoresistive properties with a reported gauge factor (GF) of up to 3000. This GF on the other hand, has been shown to be structurally dependent on the nanotubes. In contrast, to individual CNT based strain sensors, the ensemble CNT based strain sensors have very low GFs e.g. for a single walled carbon nanotube (SWCNT) thin film strain sensor, GF is ~1. As a result, studies which are mostly numerical/analytical have revealed the dependence of piezoresistivity on key parameters like concentration, orientation, length and diameter, aspect ratio, energy barrier height and Poisson ratio of polymer matrix. The fundamental understanding of the piezoresistive mechanism in an ensemble CNT based strain sensor still remains unclear, largely due to discrepancies in the outcomes of these numerical studies. Besides, there have been little or no experimental confirmation of these studies. The goal of my PhD is to study the mechanism and the optimizing principle of a SWCNT thin film strain sensor and provide experimental validation of the numerical/analytical investigations. The dependence of the piezoresistivity on key parameters like orientation, network density, bundle diameter (effective tunneling area), and length is studied, and how one can effectively optimize the piezoresistive behavior of a SWCNT thin film strain sensors. To reach this goal, my first research accomplishment involves the study of orientation of SWCNTs and its effect on the piezoresistivity of mechanically drawn SWCNT thin film based piezoresistive sensors. Using polarized Raman spectroscopy analysis and coupled electrical-mechanical test, a quantitative relationship between the strain sensitivity and SWCNT alignment order parameter was established. As compared to randomly oriented SWCNT thin films, the one with draw ratio of 3.2 exhibited ~6x increase on the GF. My second accomplishment involves studying the influence of the network density on the piezoresistivity of mechanically drawn SWCNT thin films. Mechanically drawn SWCNT thin films with different layer (or thickness) e.g. 1-layer, 3-layer, 10-layer and 20-layer SWCNT thin films were prepared to understand the variation of SWCNT network density as well as the alignment of SWCNTs on the strain sensitivity. The less entangled SWCNT bundles observed in the sparse network density (1- layer and 3-layer SWCNT thin films) allows for easy alignment and the best gauge factors. As compared to the randomly oriented SWCNT thin films, the one with draw ratio of 3.2 exhibited ~8x increase on the GF for the 1-layer SWCNT thin films while the 20-layer SWCNT thin films exhibited ~3x increase in the GF. My third accomplishment examines the effect of SWCNT bundles with different diameters on the piezoresistive behavior of mechanically drawn SWCNT thin films. SWCNT thin film network of sparse morphology (1-layer) with different bundle sizes were prepared by varying the sonication duration e.g. S0.5hr, S4hr, S10hr and S20hr and using spraying coating. The GF increased by a factor of ~10 when the randomly oriented SWCNT thin film was stretched to a draw ratio of 3.2 for the S0.5hr SWCNT thin films and by a factor of ~2 for the S20hr SWCNT thin films. Three main mechanisms were attributed to this behavior e.g. effect of concentration of exfoliated nanotubes, bundle reduction due to mechanical stretching, and influence of bundle length on the alignment of SWCNTs. Furthermore, information about the average length and length distribution is very essential when investigating the influence of individual nanotube length on the strain sensitivity. With that in mind, we would use our previously developed preparative ultracentrifuge method (PUM), and our newly developed gel electrophoresis and simultaneous Raman and photoluminescence spectroscopy (GEP-SRSPL) to characterize the average length and length distribution of individual SWCNTs respectively.

Process for forming epitaxial perovskite thin film layers using halide precursors

DOEpatents

Clem, Paul G.; Rodriguez, Mark A.; Voigt, James A.; Ashley, Carol S.

2001-01-01

A process for forming an epitaxial perovskite-phase thin film on a substrate. This thin film can act as a buffer layer between a Ni substrate and a YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor layer. The process utilizes alkali or alkaline metal acetates dissolved in halogenated organic acid along with titanium isopropoxide to dip or spin-coat the substrate which is then heated to about 700.degree. C. in an inert gas atmosphere to form the epitaxial film on the substrate. The YBCO superconductor can then be deposited on the layer formed by this invention.

Photo-EMF sensitivity of porous silicon thin layer-crystalline silicon heterojunction to ammonia adsorption.

PubMed

Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

2011-01-01

A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.

19.5%-Efficient CuIn1-xGaxSe2 Photovoltaic Cells Using A Cd-Zn-S Buffer Layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharya. R. N.

2008-01-01

CuIn1-xGaxSe2 (CIGS) solar cell junctions prepared by chemical-bath-deposited (CBD) Zn1-xCdxS (CdZnS), ZnS, and CdS buffer layers are discussed. A 19.52%-efficient, CIGS-based, thin-film photovoltaic device has been fabricated using a single-layer CBD CdZnS buffer layer. The mechanism that creates extensive hydroxide and oxide impurities in CBD-ZnS and CBD-CdZnS thin films (compared to CBD-CdS thin film) is presented.

Management of light absorption in extraordinary optical transmission based ultra-thin-film tandem solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mashooq, Kishwar; Talukder, Muhammad Anisuzzaman, E-mail: anis@eee.buet.ac.bd

2016-05-21

Although ultra-thin-film solar cells can be attractive in reducing the cost, they suffer from low absorption as the thickness of the active layer is usually much smaller than the wavelength of incident light. Different nano-photonic techniques, including plasmonic structures, are being explored to increase the light absorption in ultra-thin-film solar cells. More than one layer of active materials with different energy bandgaps can be used in tandem to increase the light absorption as well. However, due to different amount of light absorption in different active layers, photo-generated currents in different active layers will not be the same. The current mismatchmore » between the tandem layers makes them ineffective in increasing the efficiency. In this work, we investigate the light absorption properties of tandem solar cells with two ultra-thin active layers working as two subcells and a metal layer with periodically perforated holes in-between the two subcells. While the metal layer helps to overcome the current mismatch, the periodic holes increase the absorption of incident light by helping extraordinary optical transmission of the incident light from the top to the bottom subcell, and by coupling the incident light to plasmonic and photonic modes within ultra-thin active layers. We extensively study the effects of the geometry of holes in the intermediate metal layer on the light absorption properties of tandem solar cells with ultra-thin active layers. We also study how different metals in the intermediate layer affect the light absorption; how the geometry of holes in the intermediate layer affects the absorption when the active layer materials are changed; and how the intermediate metal layer affects the collection of photo-generated electron-hole pairs at the terminals. We find that in a solar cell with 6,6-phenyl C61-butyric acid methyl ester top subcell and copper indium gallium selenide bottom subcell, if the periodic holes in the metal layer are square or polygon, total absorption remains approximately the same. However, the total absorption suffers significantly if the holes are triangle. The transmission spectra of incident light into the bottom subcell, and hence the absorption, change significantly for square and circle holes if the active materials change to cadmium selenide (CdSe) and cadmium telluride (CdTe) in the top and bottom subcells, respectively. Although the intermediate metal layer may induce electron-hole pair recombination due to surface defects, the short-circuit current density of an ultra-thin plasmonic solar cell with an intermediate metal layer with two-dimensional hole array is >9% of that of a structure without the intermediate metal layer.« less

Study on the Hydrogenated ZnO-Based Thin Film Transistors. Part 1

DTIC Science & Technology

2011-04-30

IGZO film on the performance of thin film transistors 5 Chapter 2. Hydrogenation of a- IGZO channel layer in the thin film transistors 12...effect of substrate temperature during the deposition of a- IGZO film on the performance of thin film transistors Introduction The effect of substrate...temperature during depositing IGZO channel layer on the performance of amorphous indium-gallium-zinc oxide (a- IGZO

Thin-Film Power Transformers

NASA Technical Reports Server (NTRS)

Katti, Romney R.

1995-01-01

Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

Substrate spacing and thin-film yield in chemical bath deposition of semiconductor thin films

NASA Astrophysics Data System (ADS)

Arias-Carbajal Reádigos, A.; García, V. M.; Gomezdaza, O.; Campos, J.; Nair, M. T. S.; Nair, P. K.

2000-11-01

Thin-film yield in the chemical bath deposition technique is studied as a function of separation between substrates in batch production. Based on a mathematical model, it is proposed and experimentally verified in the case of CdS thin films that the film thickness reaches an asymptotic maximum with increase in substrate separation. It is shown that at a separation less than 1 mm between substrates the yield, i.e. percentage in moles of a soluble cadmium salt deposited as a thin film of CdS, can exceed 50%. This behaviour is explained on the basis of the existence of a critical layer of solution near the substrate, within which the relevant ionic species have a higher probability of interacting with the thin-film layer than of contributing to precipitate formation. The critical layer depends on the solution composition and the temperature of the bath as well as the duration of deposition. An effective value for the critical layer thickness has been defined as half the substrate separation at which 90% of the maximum film thickness for the particular bath composition, bath temperature and duration of deposition is obtained. In the case of CdS thin films studied as an example, the critical layer is found to extend from 0.5 to 2.5 mm from the substrate surface, depending on the deposition conditions.

Effects of morphological control on the characteristics of vertical-type OTFTs using Alq3.

PubMed

Kim, Young Do; Park, Jong Wook; Kang, In Nam; Oh, Se Young

2008-09-01

We have fabricated vertical-type organic thin-film transistors (OTFTs) using tris-(8-hydroxyquinoline) aluminum (Alq(3)) as an n-type active material. Vertical-type OTFT using Alq(3) has a layered structure of Al(source electrode)/Alq(3)(active layer)/Al(gate electrode)/Alq(3)(active layer)/ITO glass(drain electrode). Alq(3) thin films containing various surface morphologies could be obtained by the control of evaporation rate and substrate temperature. The effects of the morphological control of Alq(3) thin layer on the grain size and the flatness of film surface were investigated. The characteristics of vertical-type OTFT significantly influenced the growth condition of Alq(3) layer.

Disruption of vertical motility by shear triggers formation of thin phytoplankton layers.

PubMed

Durham, William M; Kessler, John O; Stocker, Roman

2009-02-20

Thin layers of phytoplankton are important hotspots of ecological activity that are found in the coastal ocean, meters beneath the surface, and contain cell concentrations up to two orders of magnitude above ambient concentrations. Current interpretations of their formation favor abiotic processes, yet many phytoplankton species found in these layers are motile. We demonstrated that layers formed when the vertical migration of phytoplankton was disrupted by hydrodynamic shear. This mechanism, which we call gyrotactic trapping, can be responsible for the thin layers of phytoplankton commonly observed in the ocean. These results reveal that the coupling between active microorganism motility and ambient fluid motion can shape the macroscopic features of the marine ecological landscape.

Enhanced electrical properties of dual-layer channel ZnO thin film transistors prepared by atomic layer deposition

NASA Astrophysics Data System (ADS)

Li, Huijin; Han, Dedong; Dong, Junchen; Yu, Wen; Liang, Yi; Luo, Zhen; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2018-05-01

The thin film transistors (TFTs) with a dual-layer channel structure combing ZnO thin layer grown at 200 °C and ZnO film grown at 120 °C by atomic layer deposition are fabricated. The dual-layer channel TFT exhibits a low leakage current of 2.8 × 10-13 A, Ion/Ioff ratio of 3.4 × 109, saturation mobility μsat of 12 cm2 V-1 s-1, subthreshold swing (SS) of 0.25 V/decade. The SS value decreases to 0.18 V/decade after the annealing treatment in O2 due to the reduction of the trap states at the channel/dielectric interface and in the bulk channel layer. The enhanced performance obtained from the dual-layer channel TFTs is due to the ability of maintaining high mobility and suppressing the increase in the off-current at the same time.

Fabrication and characterization of {110}-oriented Pb(Zr,Ti)O3 thin films on Pt/SiO2/Si substrates using PdO//Pd buffer layer

NASA Astrophysics Data System (ADS)

Oshima, Naoya; Uchiyama, Kiyoshi; Ehara, Yoshitaka; Oikawa, Takahiro; Ichinose, Daichi; Tanaka, Hiroki; Sato, Tomoya; Uchida, Hiroshi; Funakubo, Hiroshi

2017-10-01

A strongly {110}-oriented perovskite-type thin film of tetragonal Pb(Zr0.4Ti0.6)O3 (PZT) was successfully obtained on a (100)Si substrate using a {101}PdO//{111}Pd thin film as a buffer layer. The {101}PdO//{111}Pd thin film buffer layer was obtained by oxidizing {111}Pd after depositing {111}Pd on a {111}Pt/TiO x /SiO2/{100}Si substrate. Using this buffer layer, a {110} c -oriented SrRuO3 (SRO) thin film was deposited by sputtering as a bottom electrode of PZT thin films. Subsequently, the {110}-oriented PZT thin film can be deposited on a (110) c SRO thin film by metal-organic chemical deposition (MOCVD) and its properties can be compared with those of PZT thin films with other orientations of {100} and {111}. Among the {100}, {110}, {111}-oriented PZT films, the {100}-oriented one showed the largest remnant polarization, which is in good agreement with those of the PZTs epitaxially grown in the 〈100〉, 〈110〉, and 〈111〉 directions. The other properties, i.e., piezoelectricity and dielectric constants, also showed similar anisotropic tendencies, which is in good agreement with the data reported in the epitaxially grown PZTs.

Modeling of Multiphase Flow through Thin Porous Layers: Application to a Polymer Electrolyte Fuel Cell (PEFC)

NASA Astrophysics Data System (ADS)

Qin, C.; Hassanizadeh, S.

2013-12-01

Multiphase flow and species transport though thin porous layers are encountered in a number of industrial applications, such as fuel cells, filters, and hygiene products. Based on some macroscale models like the Darcy's law, to date, the modeling of flow and transport through such thin layers has been mostly performed in 3D discretized domains with many computational cells. But, there are a number of problems with this approach. First, a proper representative elementary volume (REV) is not defined. Second, one needs to discretize a thin porous medium into computational cells whose size may be comparable to the pore sizes. This suggests that the traditional models are not applicable to such thin domains. Third, the interfacial conditions between neighboring layers are usually not well defined. Last, 3D modeling of a number of interacting thin porous layers often requires heavy computational efforts. So, to eliminate the drawbacks mentioned above, we propose a new approach to modeling multilayers of thin porous media as 2D interacting continua (see Fig. 1). Macroscale 2D governing equations are formulated in terms of thickness-averaged material properties. Also, the exchange of thermodynamic properties between neighboring layers is described by thickness-averaged quantities. In Comparison to previous macroscale models, our model has the distinctive advantages of: (1) it is rigorous thermodynamics-based model; (2) it is formulated in terms of thickness-averaged material properties which are easily measureable; and (3) it reduces 3D modeling to 2D leading to a very significant reduction of computation efforts. As an application, we employ the new approach in the study of liquid water flooding in the cathode of a polymer electrolyte fuel cell (PEFC). To highlight the advantages of the present model, we compare the results of water distribution with those obtained from the traditional 3D Darcy-based modeling. Finally, it is worth noting that, for specific case studies, a number of material properties in the model need to be determined experimentally, such as mass and heat exchange coefficients between neighboring layers. Fig. 1: Schematic representation of three thin porous layers, which may exchange mass, momentum, and energy. Also, a typical averaging domain (REV) is shown. Note that the layer thickness and thus the REV height can be spatially variable. Also, in reality, the layers are tightly stacked and there is no gap between them.

Analysis of the free amino acid content in pollen of nine Asteraceae species of known allergenic activity.

PubMed

Mondal, A K; Parui, S; Mandal, S

1998-01-01

The study reports the free amino acid composition of the pollen of nine members of the family Asteraceae, i.e. Ageratum conyzoides L., Blumea oxyodonta DC., Eupatorium odoratum L., Gnaphalium indicum L., Mikania scandens Willd., Parthenium hysterophorus L., Spilanthes acmella Murr., Vernonia cinerea (L.) Lees. and Xanthium strumarium L. by thin layer chromatography. The amino acid content was found to vary from 0.5-4.0% of the total dry weight. Fourteen amino acids were identified, among which amino-n-butyric acid, aspartic acid and proline were present in almost all pollen samples. The other major amino acids present in free form included arginine, cystine, glutamic acid, glycine, isoleucine, leucine, methionine, ornithine, tryptophan and tyrosine.

Preparation and characterization of 5-(4-hydroxy-3-nitrobenzyl)-3-phenyl-2-thiohydantoin, the phenylthiohydantoin derivative of 3-nitrotyrosine.

PubMed

Lilova, A; Kleinschmidt, T; Nedkov, P; Braunitzer, G

1986-10-01

The phenylthiocarbamoyl derivative of 3-nitrotyrosine was synthesized according to the known Edman method and then converted to its phenylthiohydantoin derivative [5-(4-hydroxy-3-nitrobenzyl)-3-phenyl-2-thiohydantion] by incubation in 0.5M HCl for 24 h at room temperature. After drying over P2O5 the chromatographically pure substance could be obtained by double recrystallization from hot acetic acid. It could be established that a shorter incubation time leads to an incomplete conversion and higher temperatures cause polymerization of the product. The compounds could be characterized by thin-layer and high-performance liquid chromatography, melting point, elemental analysis as well as NMR- and absorption spectroscopy.

Effect of thin oxide layers incorporated in spin valve structures

NASA Astrophysics Data System (ADS)

Gillies, M. F.; Kuiper, A. E. T.; Leibbrandt, G. W. R.

2001-06-01

The enhancement of the magnetoresistance effect, induced by incorporating nano-oxide layers (NOLs) in a bottom-type spin valve, was studied for various preparation conditions. The effect of a NOL in the Co90Fe10 pinned layer was found to depend critically on the oxygen pressure applied to form the thin oxide film. Pressures over 10-3 Torr O2 yield oxides thicker than about 0.7 nm, which apparently deteriorate the biasing field which exists over the oxide. The magnetoresistance values can further be raised by forming a specular reflecting oxide on top of the sense layer. Promising results were obtained with an Al2O3 capping layer formed in a solid-state oxidation reaction that occurs spontaneously when a thin Al layer is deposited on the oxidized surface of the Co90Fe10 sense layer.

Water softening process

DOEpatents

Sheppard, John D.; Thomas, David G.

1976-01-01

This invention involves an improved process for softening hard water which comprises selectively precipitaing CaCO.sub.3 to form a thin layer thereof, increasing the pH of said water to precipitate magnesium as magnesium hydroxide and then filtering the resultant slurry through said layer. The CaCO.sub.3 layer serves as a thin permeable layer which has particularly useful application in cross-flow filtration applications.

Matching characteristics of different buffer layers with VO2 thin films

NASA Astrophysics Data System (ADS)

Yang, Kai; Zhang, Dongping; Liu, Yi; Guan, Tianrui; Qin, Xiaonan; Zhong, Aihua; Cai, Xingmin; Fan, Ping; Lv, Weizhong

2016-10-01

VO2 thin films were fabricated by reactive DC magnetron sputtering on different buffer layers of MgF2, Al2O3 and TiO2, respectively. The crystallinity and orientation relationship, thickness of VO2 thin films, atoms vibrational modes, optical and electrical property, surface morphology of films were characterized by X-ray diffraction, Raman scattering microscopy, step profiler, spectrophotometer, four-probe technique, and scanning electron microscopy, respectively. XRD results investigated that the films have preferential crystalline planes VO2 (011). The crystallinity of VO2 films grown on TiO2 buffer layers are superior to VO2 directly deposited on soda-lime glass. The Raman bands of the VO2 films correspond to an Ag symmetry mode of VO2 (M). The sample prepared on 100nm TiO2 buffer layer appears nanorods structure, and exhibits remarkable solar energy modulation ability as high as 5.82% in full spectrum and 23% in near infrared spectrum. Cross-sectional SEM image of the thin films samples indicate that MgF2 buffer layer has clear interface with VO2 layer. But there are serious interdiffusion phenomenons between Al2O3, TiO2 buffer layer with VO2 layer.

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

ERIC Educational Resources Information Center

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…

High performance thin film transistor with ZnO channel layer deposited by DC magnetron sputtering.

PubMed

Moon, Yeon-Keon; Moon, Dae-Yong; Lee, Sang-Ho; Jeong, Chang-Oh; Park, Jong-Wan

2008-09-01

Research in large area electronics, especially for low-temperature plastic substrates, focuses commonly on limitations of the semiconductor in thin film transistors (TFTs), in particular its low mobility. ZnO is an emerging example of a semiconductor material for TFTs that can have high mobility, while a-Si and organic semiconductors have low mobility (<1 cm2/Vs). ZnO-based TFTs have achieved high mobility, along with low-voltage operation low off-state current, and low gate leakage current. In general, ZnO thin films for the channel layer of TFTs are deposited with RF magnetron sputtering methods. On the other hand, we studied ZnO thin films deposited with DC magnetron sputtering for the channel layer of TFTs. After analyzing the basic physical and chemical properties of ZnO thin films, we fabricated a TFT-unit cell using ZnO thin films for the channel layer. The field effect mobility (micro(sat)) of 1.8 cm2/Vs and threshold voltage (Vth) of -0.7 V were obtained.

Magnetoelastic sensor for characterizing properties of thin-film/coatings

NASA Technical Reports Server (NTRS)

Bachas, Leonidas G. (Inventor); Barrett, Gary (Inventor); Grimes, Craig A. (Inventor); Kouzoudis, Dimitris (Inventor); Schmidt, Stefan (Inventor)

2004-01-01

An apparatus for determining elasticity characteristics of a thin-film layer. The apparatus comprises a sensor element having a base magnetostrictive element at least one surface of which is at least partially coated with the thin-film layer. The thin-film layer may be of a variety of materials (having a synthetic and/or bio-component) in a state or form capable of being deposited, manually or otherwise, on the base element surface, such as by way of eye-dropper, melting, dripping, brushing, sputtering, spraying, etching, evaporation, dip-coating, laminating, etc. Among suitable thin-film layers for the sensor element of the invention are fluent bio-substances, thin-film deposits used in manufacturing processes, polymeric coatings, paint, an adhesive, and so on. A receiver, preferably remotely located, is used to measure a plurality of values for magneto-elastic emission intensity of the sensor element in either characterization: (a) the measure of the plurality of values is used to identify a magneto-elastic resonant frequency value for the sensor element; and (b) the measure of the plurality of successive values is done at a preselected magneto-elastic frequency.

Scavenging of oxygen from SrTiO3 by metals and its implications for oxide thin film deposition

NASA Astrophysics Data System (ADS)

Posadas, Agham; Kormondy, Kristy; Guo, Wei; Ponath, Patrick; Kremer, Jacqueline; Hadamek, Tobias; Demkov, Alexander

SrTiO3 is a widely used substrate for the growth of other functional oxide thin films. However, SrTiO3 loses oxygen very easily during oxide thin film deposition even under relatively high oxygen pressures. In some cases, there will be an interfacial layer of oxygen-deficient SrTiO3 formed at the interface with the deposited oxide film, depending on the metals present in the film. By depositing a variety of metals layer by layer and measuring the evolution of the core level spectra of both the deposited metal and SrTiO3 using x-ray photoelectron spectroscopy, we show that there are three distinct types of behavior that occur for thin metal films on SrTiO3. We discuss the implications of these types of behavior for the growth of complex oxide thin films on SrTiO3, and which oxide thin films are expected to produce an interfacial oxygen-deficient layer depending on their elemental constituents.

High-Efficiency Polycrystalline CdS/CdTe Solar Cells on Buffered Commercial TCO-Coated Glass

NASA Astrophysics Data System (ADS)

Colegrove, E.; Banai, R.; Blissett, C.; Buurma, C.; Ellsworth, J.; Morley, M.; Barnes, S.; Gilmore, C.; Bergeson, J. D.; Dhere, R.; Scott, M.; Gessert, T.; Sivananthan, Siva

2012-10-01

Multiple polycrystalline CdS/CdTe solar cells with efficiencies greater than 15% were produced on buffered, commercially available Pilkington TEC Glass at EPIR Technologies, Inc. (EPIR, Bolingbrook, IL) and verified by the National Renewable Energy Laboratory (NREL). n-CdS and p-CdTe were grown by chemical bath deposition (CBD) and close space sublimation, respectively. Samples with sputter-deposited CdS were also investigated. Initial results indicate that this is a viable dry-process alternative to CBD for production-scale processing. Published results for polycrystalline CdS/CdTe solar cells with high efficiencies are typically based on cells using research-grade transparent conducting oxides (TCOs) requiring high-temperature processing inconducive to low-cost manufacturing. EPIR's results for cells on commercial glass were obtained by implementing a high-resistivity SnO2 buffer layer and by optimizing the CdS window layer thickness. The high-resistivity buffer layer prevents the formation of CdTe-TCO junctions, thereby maintaining a high open-circuit voltage and fill factor, whereas using a thin CdS layer reduces absorption losses and improves the short-circuit current density. EPIR's best device demonstrated an NREL-verified efficiency of 15.3%. The mean efficiency of hundreds of cells produced with a buffer layer between December 2010 and June 2011 is 14.4%. Quantum efficiency results are presented to demonstrate EPIR's progress toward NREL's best-published results.

Extraordinary Corrosion Protection from Polymer-Clay Nanobrick Wall Thin Films.

PubMed

Schindelholz, Eric J; Spoerke, Erik D; Nguyen, Hai-Duy; Grunlan, Jaime C; Qin, Shuang; Bufford, Daniel C

2018-06-20

Metals across all industries demand anticorrosion surface treatments and drive a continual need for high-performing and low-cost coatings. Here we demonstrate polymer-clay nanocomposite thin films as a new class of transparent conformal barrier coatings for protection in corrosive atmospheres. Films assembled via layer-by-layer deposition, as thin as 90 nm, are shown to reduce copper corrosion rates by >1000× in an aggressive H 2 S atmosphere. These multilayer nanobrick wall coatings hold promise as high-performing anticorrosion treatment alternatives to costlier, more toxic, and less scalable thin films, such as graphene, hexavalent chromium, or atomic-layer-deposited metal oxides.

Effects of V2O5/Au bi-layer electrodes on the top contact Pentacene-based organic thin film transistors

NASA Astrophysics Data System (ADS)

Borthakur, Tribeni; Sarma, Ranjit

2017-05-01

Top-contact Pentacene-based organic thin film transistors (OTFTs) with a thin layer of Vanadium Pent-oxide between Pentacene and Au layer are fabricated. Here we have found that the devices with V2O5/Au bi-layer source-drain electrode exhibit better field-effect mobility, high on-off ratio, low threshold voltage and low sub-threshold slope than the devices with Au only. The field-effect mobility, current on-off ratio, threshold voltage and sub-threshold slope of V2O5/Au bi-layer OTFT estimated from the device with 15 nm thick V2O5 layer is .77 cm2 v-1 s-1, 7.5×105, -2.9 V and .36 V/decade respectively.

Vertical III-nitride thin-film power diode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wierer, Jr., Jonathan; Fischer, Arthur J.; Allerman, Andrew A.

2017-03-14

A vertical III-nitride thin-film power diode can hold off high voltages (kV's) when operated under reverse bias. The III-nitride device layers can be grown on a wider bandgap template layer and growth substrate, which can be removed by laser lift-off of the epitaxial device layers grown thereon.

Carbon-Nanotube Conductive Layers for Thin-Film Solar Cells

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2005-01-01

Thin, transparent layers comprising mats of carbon nanotubes have been proposed for providing lateral (that is, inplane) electrical conductivities for collecting electric currents from the front surfaces of the emitter layers of thin-film solar photovoltaic cells. Traditionally, thin, semitransparent films of other electrically conductive materials (usually, indium tin oxide, zinc oxide, or cadmium sulfide) have been used for this purpose. As in the cases of the traditional semitransparent conductive films, the currents collected by the nanotube layers would, in turn, be further collected by front metal contact stripes. Depending on details of a specific solar-cell design, the layer of carbon nanotubes would be deposited in addition to, or instead of, a semitransparent layer of one of these traditional conductive materials (see figure). The proposal is expected to afford the following advantages: The electrical conductivity of the carbon- nanotube layer would exceed that of the corresponding semitransparent layer of traditional electrically conductive material. The greater electrical conductivity of the carbon-nanotube layer would make it possible to retain adequate lateral electrical conductivity while reducing the thickness of, or eliminating entirely, the traditional semitransparent conductive layer. As a consequence of thinning or elimination of the traditional semitransparent conductive layer, less light would be absorbed, so that more of the incident light would be available for photovoltaic conversion. The greater electrical conductivity of the carbon-nanotube layer would make it possible to increase the distance between front metal contact stripes, in addition to (or instead of) thinning or eliminating the layer of traditional semitransparent conductive material. Consequently, the fraction of solar-cell area shadowed by front metal contact stripes would be reduced again, making more of the incident light available for photovoltaic conversion. The electrical conductivities of individual carbon nanotubes can be so high that the mat of carbon nanotubes could be made sparse enough to be adequately transparent while affording adequate lateral electrical conductivity of the mat as a whole. The thickness of the nanotube layer would be chosen so that the layer would contribute significant lateral electrical conductivity, yet would be as nearly transparent as possible to incident light. A typical thickness for satisfying these competing requirements is expected to lie between 50 and 100 nm. The optimum thickness must be calculated by comparing the lateral electrical conductivity, the distance between front metal stripes, and the amount of light lost by absorption in the nanotube layer.

Efficacy and durability of ultraviolet tints in CR-39 ophthalmic lenses.

PubMed

Lee, D Y; Brown, W L; Trachimowicz, R

1997-11-01

Ocular protection from solar ultraviolet (UV) radiation has been emphasized in recent years as a result of the thinning of the ozone layer in the atmosphere. The purpose of this study was to evaluate the absorptive properties of UV tints in CR-39 lenses. We used a spectrophotometer to measure the UV transmittance of three groups of UV tinted CR-39 lenses, including (1) lenses tinted by local optical laboratories: (2) lenses tinted by us, using commercially available dyes: and (3) stock UV lenses that have UV absorptive molecules throughout the lens. We also tested the durability of these tints to daily washing/drying by measuring their UV transmittance characteristics at 3, 6, and 12 months. All the tested lenses absorbed all of the UV-B and at least 99% of UV-A. The durability of these UV tints when exposed to daily washing/drying was excellent: all lenses continued to absorb all of the UV-B and at least 99% of UV-A after 1 year. These data suggest that UV tinted CR-39 lenses provide protection against UV radiation that meets the ANSI Z80.3-1996 Standard for non-prescription sunglasses and fashion eyewear. Furthermore, normal daily washing/drying for 1 year does not cause a significant decrease in the protective effect of the UV tint.

Electromagnetic shielding effectiveness of a thin silver layer deposited onto PET film via atmospheric pressure plasma reduction

NASA Astrophysics Data System (ADS)

Oh, Hyo-Jun; Dao, Van-Duong; Choi, Ho-Suk

2018-03-01

This study presents the first use of a plasma reduction reaction under atmospheric pressure to fabricate a thin silver layer on polyethylene terephthalate (PET) film without the use of toxic chemicals, high voltages, or an expensive vacuum apparatus. The developed film is applied to electromagnetic interference (EMI) shielding. After repeatedly depositing a silver layer through a plasma reduction reaction on PET, we can successfully fabricate a uniformly deposited thin silver layer. It was found that both the particle size and film thickness of thin silver layers fabricated at different AgNO3 concentrations increase with an increase in the concentration of AgNO3. However, the roughness of the thin silver layer decreases when increasing the concentration of AgNO3 from 100 to 500 mM, and the roughness increases with a further increase in the concentration of AgNO3. The EMI shielding effectiveness (SE) of the film is measured in the frequency range of 0.045 to 1 GHz. As a result of optimizing the electrical conductivity by measuring sheet resistance of the thin silver layer, the film fabricated from 500 mM AgNO3 exhibits the highest EMI SE among all fabricated films. The maximum values of the EMI SE are 60.490 dB at 0.1 GHz and 54.721 dB at 1.0 GHz with minimum sheet resistance of 0.244 Ω/□. Given that the proposed strategy is simple and effective, it is promising for fabricating various low-cost metal films with high EMI SE.

ON AERODYNAMIC AND BOUNDARY LAYER RESISTANCES WITHIN DRY DEPOSITION MODELS

EPA Science Inventory

There have been many empirical parameterizations for the aerodynamic and boundary layer resistances proposed in the literature, e.g. those of the Meyers Multi-Layer Deposition Model (MLM) used with the nation-wide dry deposition network. Many include arbitrary constants or par...

Comparison of reproduce signal and noise of conventional and keepered CoCrTa/Cr thin film media

NASA Astrophysics Data System (ADS)

Sin, Kyusik; Ding, Juren; Glijer, Pawel; Sivertsen, John M.; Judy, Jack H.; Zhu, Jian-Gang

1994-05-01

We studied keepered high coercivity CoCrTa/Cr thin film media with a Cr isolation layer between the CoCrTa storage and an overcoating of an isotropic NiFe soft magnetic layer. The influence of the thickness of the NiFe and Cr layers, and the effects of head bias current on the signal output and noise, were studied using a thin film head. The reproduced signal increased by 7.3 dB, but the signal-to-noise ratio decreased by 4 dB at a linear density of 2100 fr/mm (53.3 kfr/in.) with a 1000 Å thick NiFe keeper layer. The medium noise increased with increasing NiFe thickness and the signal output decreased with decreasing Cr thickness. A low output signal obtained with very thin Cr may be due to magnetic interactions between the keeper layer and magnetic media layer. It is observed that signal distortion and timing asymmetry of the output signals depend on the thickness of the keeper layer and the head bias current. The signal distortion increased and the timing asymmetry decreased as the head bias current was increased. These results may be associated with different permeability of the keeper under the poles of the thin film head due to the superposition of head bias and bit fields.

Corrosion protection of steel by thin coatings of starch-oil dry lubricants

USDA-ARS?s Scientific Manuscript database

Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. Dry lubricants reduce friction between two metal surfaces. This research investigated the inhibition of corrosive behavior a dry lubricant formulation consisting of jet-cooked corn starch and soyb...

Multiple-layered effective medium approximation approach to modeling environmental effects on alumina passivated highly porous silicon nanostructured thin films measured by in-situ Mueller matrix ellipsometry

NASA Astrophysics Data System (ADS)

Mock, Alyssa; Carlson, Timothy; VanDerslice, Jeremy; Mohrmann, Joel; Woollam, John A.; Schubert, Eva; Schubert, Mathias

2017-11-01

Optical changes in alumina passivated highly porous silicon slanted columnar thin films during controlled exposure to toluene vapor are reported. Electron-beam evaporation glancing angle deposition and subsequent atomic layer deposition are utilized to deposit alumina passivated nanostructured porous silicon thin films. In-situ Mueller matrix generalized spectroscopic ellipsometry in an environmental cell is then used to determine changes in optical properties of the nanostructured thin films by inspection of individual Mueller matrix elements, each of which exhibit sensitivity to adsorption. The use of a multiple-layered effective medium approximation model allows for accurate description of the inhomogeneous nature of toluene adsorption onto alumina passivated highly porous silicon slanted columnar thin films.

Effect of Selectively Etched Ferroelectric Thin-Film Layer on the Performance of a Tunable Bandpass Filter

NASA Technical Reports Server (NTRS)

Subramanyam, Guru; Vignesparamoorthy, Sivaruban; Mueller, Carl; VanKeuls, Fred; Warner, Joseph; Miranda, Felix A.

2001-01-01

The main purpose of this work is to study the effect of a selectively etched ferroelectric thin film layer on the performance of an electrically tunable filter. An X-band tunable filter was designed, fabricated and tested on a selectively etched Barium Strontium Titanate (BSTO) ferroelectric thin film layer. Tunable filters with varying lengths of BSTO thin-film in the input and output coupling gaps were modeled, as well as experimentally tested. Experimental results showed that filters with coupling gaps partially filled with BSTO maintained frequency tunability and improved the insertion loss by approx. 2dB. To the best of our knowledge, these results represent the first experimental demonstration of the advantages of selective etching in the performance of thin film ferroelectric-based tunable microwave components.

Fabrication of Hydrogenated Diamond Metal-Insulator-Semiconductor Field-Effect Transistors.

PubMed

Liu, Jiangwei; Koide, Yasuo

2017-01-01

Diamond is regarded as a promising material for fabrication of high-power and high-frequency electronic devices due to its remarkable intrinsic properties, such as wide band gap energy, high carrier mobility, and high breakdown field. Meanwhile, since diamond has good biocompatibility, long-term durability, good chemical inertness, and a large electron-chemical potential window, it is a suitable candidate for the fabrication of biosensors. Here, we demonstrate the fabrication of hydrogenated diamond (H-diamond) based metal-insulator-semiconductor field-effect transistors (MISFETs). The fabrication is based on the combination of laser lithography, dry-etching, atomic layer deposition (ALD), sputtering deposition (SD), electrode evaporation, and lift-off techniques. The gate insulator is high-k HfO 2 with a SD/ALD bilayer structure. The thin ALD-HfO 2 film (4.0 nm) acts as a buffer layer to prevent the hydrogen surface of the H-diamond from plasma discharge damage during the SD-HfO 2 deposition. The growth of H-diamond epitaxial layer, fabrication of H-diamond MISFETs, and electrical property measurements for the MISFETs is demonstrated. This chapter explains the fabrication of H-diamond FET based biosensors.

Grafted Polystyrene Monolayer Brush as Both Negative and Positive Tone Electron Beam Resist.

PubMed

Aydinoglu, Ferhat; Yamada, Hirotaka; Dey, Ripon K; Cui, Bo

2017-05-23

Although spin coating is the most widely used electron-beam resist coating technique in nanolithography, it cannot typically be applied for nonflat or irregular surfaces. Here, we demonstrate that monolayer polystyrene brush can be grafted on substrates and used as both positive and negative electron-beam resist, which can be applied for such unconventional surfaces. Polystyrene is a popular negative resist when using solvent developer but solvent cannot be used for grafted polystyrene brush that is firmly bonded to the substrate. Instead, we employed two unconventional development methods to lead polystyrene brush to positive or negative tone behavior. Negative tone was achieved by thermal development at 300 °C because exposed thus cross-linked polystyrene brush is more thermally stable against vaporization than unexposed linear one. Surprisingly, positive tone behavior occurred when the brush was grafted onto an aluminum (Al) layer and the film stack was developed using diluted hydrofluoric acid (HF) that etched the underlying Al layer. By transferring the patterns into the silicon (Si) substrates using the thin Al layer as a sacrificial hard mask for dry etch, well-defined structures in Si were obtained in two different electron-beam resist tones as well as in nonflat surfaces.

Flow Visualization by Elastic Light Scattering in the Boundary Layer of a Supersonic Flow

NASA Technical Reports Server (NTRS)

Herring, G. C.; Hillard, Mervin E., Jr.

2000-01-01

We demonstrate instantaneous flow visualization of the boundary layer region of a Mach 2.5 supersonic flow over a flat plate that is interacting with an impinging shock wave. Tests were performed in the Unitary Plan Wind Tunnel (UPWT) at NASA Langley Research Center. The technique is elastic light scattering using 10-nsec laser pulses at 532 nm. We emphasize that no seed material of any kind, including water (H2O), is purposely added to the flow. The scattered light comes from a residual impurity that normally exists in the flow medium after the air drying process. Thus, the technique described here differs from the traditional vapor-screen method, which is typically accomplished by the addition of extra H2O vapor to the airflow. The flow is visualized with a series of thin two-dimensional light sheets (oriented perpendicular to the streamwise direction) that are located at several positions downstream of the leading edge of the model. This geometry allows the direct observation of the unsteady flow structure in the spanwise dimension of the model and also allows the indirect observation of the boundary layer growth in the streamwise dimension.

Mechanical Properties and Tribological Behavior of In Situ NbC/Fe Surface Composites

NASA Astrophysics Data System (ADS)

Cai, Xiaolong; Zhong, Lisheng; Xu, Yunhua

2017-01-01

The mechanical properties and tribological behavior of the niobium carbide (NbC)-reinforced gray cast iron surface composites prepared by in situ synthesis have been investigated. Composites are comprised of a thin compound layer and followed by a deep diffusion zone on the surface of gray cast iron. The graded distributions of the hardness and elastic modulus along the depth direction of the cross section of composites form in the ranges of 6.5-20.1 and 159.3-411.2 GPa, respectively. Meanwhile, dry wear tests for composites were implemented on pin-on-disk equipment at sliding speed of 14.7 × 10-2 m/s and under 5 or 20 N, respectively. The result indicates that tribological performances of composites are considerably dependent on the volume fraction and the grain size of the NbC as well as the mechanical properties of the matrices in different areas. The surface compound layer presents the lowest coefficient of friction and wear rate, and exhibits the highest wear resistance, in comparison with diffusion zone and substrate. Furthermore, the worn morphologies observed reveal the dominant wear mechanism is abrasive wear feature in compound layer and diffusion zone.

Surface layer formation of LiCoO2 thin film electrodes in non-aqueous electrolyte containing lithium bis(oxalate)borate

NASA Astrophysics Data System (ADS)

Matsui, Masaki; Dokko, Kaoru; Akita, Yasuhiro; Munakata, Hirokazu; Kanamura, Kiyoshi

2012-07-01

Surface layer formation processes on a LiCoO2 thin film electrode in a non-aqueous electrolyte containing lithium bis(oxalate)borate (LiBOB) were investigated using in situ FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). The in situ FTIR spectra of the electrolyte solution containing LiBOB showed that the adsorption of BOB anions on the electrode surface occurred during the charge process of the LiCoO2 thin film electrode above 4.0 V. XPS analysis for the LiCoO2 thin film electrode charged in an electrolyte containing LiBOB suggested that the adsorbed BOB anions on the electrode surface prevent the continuous decomposition of hexafluorophosphate (PF6) anions resulting in the formation of a very thin surface layer containing organic species, while the LiCoO2 charged in a LiPF6 solution had a relatively thick surface layer containing organic species and inorganic species.

Nanofiber based triple layer hydro-philic/-phobic membrane - a solution for pore wetting in membrane distillation

PubMed Central

Prince, J. A.; Rana, D.; Matsuura, T.; Ayyanar, N.; Shanmugasundaram, T. S.; Singh, G.

2014-01-01

The innovative design and synthesis of nanofiber based hydro-philic/phobic membranes with a thin hydro-phobic nanofiber layer on the top and a thin hydrophilic nanofiber layer on the bottom of the conventional casted micro-porous layer which opens up a solution for membrane pore wetting and improves the pure water flux in membrane distillation. PMID:25377488

Burning Graphene Layer-by-Layer

PubMed Central

Ermakov, Victor A.; Alaferdov, Andrei V.; Vaz, Alfredo R.; Perim, Eric; Autreto, Pedro A. S.; Paupitz, Ricardo; Galvao, Douglas S.; Moshkalev, Stanislav A.

2015-01-01

Graphene, in single layer or multi-layer forms, holds great promise for future electronics and high-temperature applications. Resistance to oxidation, an important property for high-temperature applications, has not yet been extensively investigated. Controlled thinning of multi-layer graphene (MLG), e.g., by plasma or laser processing is another challenge, since the existing methods produce non-uniform thinning or introduce undesirable defects in the basal plane. We report here that heating to extremely high temperatures (exceeding 2000 K) and controllable layer-by-layer burning (thinning) can be achieved by low-power laser processing of suspended high-quality MLG in air in “cold-wall” reactor configuration. In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates. Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification. The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material. PMID:26100466

Experimental research of solid waste drying in the process of thermal processing

NASA Astrophysics Data System (ADS)

Bukhmirov, V. V.; Kolibaba, O. B.; Gabitov, R. N.

2015-10-01

The convective drying process of municipal solid waste layer as a polydispersed multicomponent porous structure is studied. On the base of the experimental data criterial equations for calculating heat transfer and mass transfer processes in the layer, depending on the humidity of the material, the speed of the drying agent and the layer height are obtained. These solutions are used in the thermal design of reactors for the thermal processing of multicomponent organic waste.

The effects of gamma-ray irradiation on organic materials of different conjugation lengths

NASA Astrophysics Data System (ADS)

Zhang, Cheng; Taylor, Edward W.

2009-08-01

The radiation resistance of organic electro-optic and optoelectronic materials of different conjugation lengths for space applications is receiving increased attention. Earlier investigation reported that guest-host (G-H) poled polymer EO modulator devices composed of a phenyltetraene bridge-type chromophore in amorphous polycarbonate (CLD/APC) did not exhibit a decrease in EO response (i.e., an increase in modulation-switching voltage- Vπ) following irradiation by low dose [10-160 krad(Si)] 60Co gamma-rays. In this work, the post-irradiation responses of 60Co gamma-rays on CLD1/APC thin films are examined by various chemical and spectroscopic methods including: a solubility test, thin-layer chromatography, proton nuclear magnetic resonance spectroscopy, UV-vis absorption, and infra-red absorption. The results indicate that CLD1 and APC did not decompose under gamma-ray irradiation at dose levels ranging from 66-274 krad(Si) and from 61-154 krad(Si), respectively which support the previously reported data. A comparison with an in situ proton irradiated DRI/PMMA material is also presented.

Polymer mediated layer-by-layer assembly of different shaped gold nanoparticles.

PubMed

Budy, Stephen M; Hamilton, Desmond J; Cai, Yuheng; Knowles, Michelle K; Reed, Scott M

2017-02-01

Gold nanoparticles (GNPs) have a wide range of properties with potential applications in electronics, optics, catalysis, and sensing. In order to demonstrate that dense, stable, and portable samples could be created for these applications, multiple layers of GNPs were assembled via drop casting on glass substrates by layer-by-layer (LBL) techniques. Two cationic polyelectrolytes, poly(diallyldimethylammonium chloride) and polyethyleneimine, one anionic polyelectrolyte, poly(sodium 4-styrene sulfonate), and one neutral polymer, polyvinylpyrrolidone, were combined with four different shapes of GNPs (spherical, rod, triangular prismatic, and octahedral) to prepare thin films. A subset of these polymer nanoparticle combinations were assembled into thin films. Synthesized GNPs were characterized via dynamic light scattering, UV-vis spectroscopy, and transmission electron microscopy and the LBL thin films were characterized using UV-vis spectroscopy and atomic force microscopy. Sensing applications of the nanoparticles in solution and thin films were tested by monitoring the localized surface plasmon resonance of the GNPs. LBL thin films were prepared ranging from 25 to 100 layers with optical densities at plasmon from 0.5 to 3.0. Sensitivity in solutions ranged from 14 to 1002nm/refractive index units (RIU) and films ranged from 18.8 to 135.1nm/RIU suggesting reduced access to the GNPs within the films. Copyright © 2016 Elsevier Inc. All rights reserved.

Stepwise crystallization and the layered distribution in crystallization kinetics of ultra-thin poly(ethylene terephthalate) film

NASA Astrophysics Data System (ADS)

Zuo, Biao; Xu, Jianquan; Sun, Shuzheng; Liu, Yue; Yang, Juping; Zhang, Li; Wang, Xinping

2016-06-01

Crystallization is an important property of polymeric materials. In conventional viewpoint, the transformation of disordered chains into crystals is usually a spatially homogeneous process (i.e., it occurs simultaneously throughout the sample), that is, the crystallization rate at each local position within the sample is almost the same. Here, we show that crystallization of ultra-thin poly(ethylene terephthalate) (PET) films can occur in the heterogeneous way, exhibiting a stepwise crystallization process. We found that the layered distribution of glass transition dynamics of thin film modifies the corresponding crystallization behavior, giving rise to the layered distribution of the crystallization kinetics of PET films, with an 11-nm-thick surface layer having faster crystallization rate and the underlying layer showing bulk-like behavior. The layered distribution in crystallization kinetics results in a particular stepwise crystallization behavior during heating the sample, with the two cold-crystallization temperatures separated by up to 20 K. Meanwhile, interfacial interaction is crucial for the occurrence of the heterogeneous crystallization, as the thin film crystallizes simultaneously if the interfacial interaction is relatively strong. We anticipate that this mechanism of stepwise crystallization of thin polymeric films will allow new insight into the chain organization in confined environments and permit independent manipulation of localized properties of nanomaterials.

Stepwise crystallization and the layered distribution in crystallization kinetics of ultra-thin poly(ethylene terephthalate) film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuo, Biao, E-mail: chemizuo@zstu.edu.cn, E-mail: wxinping@yahoo.com; Xu, Jianquan; Sun, Shuzheng

2016-06-21

Crystallization is an important property of polymeric materials. In conventional viewpoint, the transformation of disordered chains into crystals is usually a spatially homogeneous process (i.e., it occurs simultaneously throughout the sample), that is, the crystallization rate at each local position within the sample is almost the same. Here, we show that crystallization of ultra-thin poly(ethylene terephthalate) (PET) films can occur in the heterogeneous way, exhibiting a stepwise crystallization process. We found that the layered distribution of glass transition dynamics of thin film modifies the corresponding crystallization behavior, giving rise to the layered distribution of the crystallization kinetics of PET films,more » with an 11-nm-thick surface layer having faster crystallization rate and the underlying layer showing bulk-like behavior. The layered distribution in crystallization kinetics results in a particular stepwise crystallization behavior during heating the sample, with the two cold-crystallization temperatures separated by up to 20 K. Meanwhile, interfacial interaction is crucial for the occurrence of the heterogeneous crystallization, as the thin film crystallizes simultaneously if the interfacial interaction is relatively strong. We anticipate that this mechanism of stepwise crystallization of thin polymeric films will allow new insight into the chain organization in confined environments and permit independent manipulation of localized properties of nanomaterials.« less

Approximate transient and long time limit solutions for the band broadening induced by the thin sidewall-layer in liquid chromatography columns.

PubMed

Broeckhoven, Ken; Desmet, Gert

2007-11-16

Using a combination of both analytical and numerical techniques, approximate analytical expressions have been established for the transient and long time limit band broadening, originating from the presence of a thin disturbed sidewall layer in liquid chromatography columns, including packed, monolithic as well as microfabricated columns. The established expressions can be used to compare the importance of a thin disturbed sidewall layer with that of other radial heterogeneity effects (such as transcolumn packing density variations due to the relief of packing stresses). The expressions are independent of the actual velocity profile inside the layer as long as the disturbed sidewall layer occupies less than 2.5% of the column width.

Enhancement of absorption and color contrast in ultra-thin highly absorbing optical coatings

NASA Astrophysics Data System (ADS)

Kats, Mikhail A.; Byrnes, Steven J.; Blanchard, Romain; Kolle, Mathias; Genevet, Patrice; Aizenberg, Joanna; Capasso, Federico

2013-09-01

Recently a new class of optical interference coatings was introduced which comprises ultra-thin, highly absorbing dielectric layers on metal substrates. We show that these lossy coatings can be augmented by an additional transparent subwavelength layer. We fabricated a sample comprising a gold substrate, an ultra-thin film of germanium with a thickness gradient, and several alumina films. The experimental reflectivity spectra showed that the additional alumina layer increases the color range that can be obtained, in agreement with calculations. More generally, this transparent layer can be used to enhance optical absorption, protect against erosion, or as a transparent electrode for optoelectronic devices.

High Performance 50 nm InAlAs/In0.75GaAs Metamorphic High Electron Mobility Transistors with Si3N4 Passivation on Thin InGaAs Layer

NASA Astrophysics Data System (ADS)

Yeon, Seongjin; Seo, Kwangseok

2008-04-01

We fabricated 50 nm InAlAs/InGaAs metamorphic high electron mobility transistors (HEMTs) with a very thin barrier. Through the reduction of the gate-channel distance (dGC) in the epitaxial structure, a channel aspect ratio (ARC) of over three was achieved when Lg was 50 nm. We inserted a thin InGaAs layer as a protective layer, and tested various gate structures to reduce surface problems induced by barrier shrinkage and to optimize the device characteristics. Through the optimization of the gate structure with the thin InGaAs layer, the fabricated 50 nm metamorphic HEMT exhibited high DC and RF characteristics, Gm of 1.5 S/mm, and fT of 490 GHz.

Frontally eluted components procedure with thin layer chromatography as a mode of sample preparation for high performance liquid chromatography quantitation of acetaminophen in biological matrix.

PubMed

Klimek-Turek, A; Sikora, M; Rybicki, M; Dzido, T H

2016-03-04

A new concept of using thin-layer chromatography to sample preparation for the quantitative determination of solute/s followed by instrumental techniques is presented Thin-layer chromatography (TLC) is used to completely separate acetaminophen and its internal standard from other components (matrix) and to form a single spot/zone containing them at the solvent front position (after the final stage of the thin-layer chromatogram development). The location of the analytes and internal standard in the solvent front zone allows their easy extraction followed by quantitation by HPLC. The exctraction procedure of the solute/s and internal standard can proceed from whole solute frontal zone or its part without lowering in accuracy of quantitative analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of nanocrystal ink based superstrate-type CuInS₂ thin film solar cells.

PubMed

Cho, Jin Woo; Park, Se Jin; Kim, Woong; Min, Byoung Koun

2012-07-05

A CuInS₂ (CIS) nanocrystal ink was applied to thin film solar cell devices with superstrate-type configuration. Monodispersed CIS nanocrystals were synthesized by a colloidal synthetic route and re-dispersed in toluene to form an ink. A spray method was used to coat CIS films onto conducting glass substrates. Prior to CIS film deposition, TiO₂ and CdS thin films were also prepared as a blocking layer and a buffer layer, respectively. We found that both a TiO₂ blocking layer and a CdS buffer layer are necessary to generate photoresponses in superstrate-type devices. The best power conversion efficiency (∼1.45%) was achieved by the CIS superstrate-type thin film solar cell device with 200 and 100 nm thick TiO₂ and CdS films, respectively.

Synthesis and Characterization of Hydrophobic Silica Thin Layer Derived from Methyltrimethoxysilane (MTMS)

NASA Astrophysics Data System (ADS)

Darmawan, Adi; Utari, Riyadini; Eka Saputra, Riza; Suhartana; Astuti, Yayuk

2018-01-01

This study investigated the synthesis and characterization of MTMS hydrophobic silica prepared by sol-gel method. In principle, silica xerogels and silica thin layer were obtained by reacting MTMS in ethanol solvent in some pH variations. The MTMS solution was used to modify the surface of the ceramic plate by dipcoating method to further be calcined at two different temperatures of 350°C and 500°C. The silica xerogels were analysed by FTIR, TGA-DSC and GSA to determine functional group characteristics, thermal properties and pore morphology respectively. Meanwhile, the silica thin layers were analysed their hydrophobic properties using water contact angle measurement and surface roughness determination using SEM. The results showed that the higher the pH used in the MTMS solution, the higher the resulting contact angle. The highest contact angle was obtained at pH 8.12 which reached 94.7° and 79.5° for silica thin layer calcined at 350°C and 500°C, respectively. The TGA results indicated that the methyl group survived up to 400°C and disappeared at 500°C which had implications on silica thin layer hydrophobic nature. GSA result exhibited that the silica xerogel had a close structure with a very low pore volume. While the SEM-EDX results displayed that the silica thin layer prepared at acidic pH had smoother surface morphology and became rough when prepared at an alkaline pH.

Ion-Implanted Diamond Films and Their Tribological Properties

NASA Technical Reports Server (NTRS)

Wu, Richard L. C.; Miyoshi, Kazuhisa; Korenyi-Both, Andras L.; Garscadden, Alan; Barnes, Paul N.

1993-01-01

This paper reports the physical characterization and tribological evaluation of ion-implanted diamond films. Diamond films were produced by microwave plasma, chemical vapor deposition technique. Diamond films with various grain sizes (0.3 and 3 microns) and roughness (9.1 and 92.1 nm r.m.s. respectively) were implanted with C(+) (m/e = 12) at an ion energy of 160 eV and a fluence of 6.72 x 10(exp 17) ions/sq cm. Unidirectional sliding friction experiments were conducted in ultrahigh vacuum (6.6 x 10(exp -7)Pa), dry nitrogen and humid air (40% RH) environments. The effects of C(+) ion bombardment on fine and coarse-grained diamond films are as follows: the surface morphology of the diamond films did not change; the surface roughness increased (16.3 and 135.3 nm r.m.s.); the diamond structures were damaged and formed a thin layer of amorphous non-diamond carbon; the friction coefficients dramatically decreased in the ultrahigh vacuum (0.1 and 0.4); the friction coefficients decreased slightly in the dry nitrogen and humid air environments.

Optimization of Chitosan Drying Temperature on The Quality and Quantity of Edible Film

NASA Astrophysics Data System (ADS)

Sri Wahyuni, Endah; Arifan, Fahmi

2018-02-01

Edible film is a thin layer (biodegradable) used to coat food and can be eaten. In addition edible film serves as a vapor transfer inhibitor, inhibits gas exchange, prevents aroma loss, prevents fat transfer, improves physical characteristics, and as an additive carrier. Edible film made of cassava starch, glycerol and chitosan. Cassava starch is used as raw material because it contains 80% starch. Glycerol serves as a plasticizer and chitosan serves to form films and membranes well. The purpose of this research is to know the characteristic test of edible film by using ANOVA analysis, where the variable of drying of the oven is temperature (70°C, 80°C, 90°C) and time for 3 hours and variables change chitosan (2 gr, 3 gr, 4 gr). The result of this research was obtained the most optimum for water content and water resistance in temperature variable 80 °C and chitosan 4 gr. The best edible films and bubbles on temperature variables are 80 °C and chitosan 4 gr.

Numerical Simulation of Thin Film Breakup on Nonwettable Surfaces

NASA Astrophysics Data System (ADS)

Suzzi, N.; Croce, G.

2017-01-01

When a continuous film flows on a nonwettable substrate surface, it may break up, with the consequent formation of a dry-patch. The actual shape of the resulting water layer is of great interest in several engineering applications, from in-flight icing simulation to finned dehumidifier behavior modeling. Here, a 2D numerical solver for the prediction of film flow behavior is presented. The effect of the contact line is introduced via the disjoining pressure terms, and both gravity and shear are included in the formulation. The code is validated with literature experimental data for the case of a stationary dry-patch on an inclined plane. Detailed numerical results are compared with literature simplified model prediction. Numerical simulation are then performed in order to predict the threshold value of the film thickness allowing for film breakup and to analyze the dependence of the dynamic contact angle on film velocity and position along the contact line. Those informations will be useful in order to efficiently predict more complex configuration involving multiple breakups on arbitrarily curved substrate surfaces (as those involved in in-flight icing phenomena on aircraft).

Substrate attributes determine gait in a terrestrial gastropod.

PubMed

McKee, Amberle; Voltzow, Janice; Pernet, Bruno

2013-02-01

Some terrestrial gastropods are able to move using two gaits: adhesive crawling, where the entire foot is separated from the substrate only by a thin layer of mucus and the snail leaves a continuous mucus trail; and loping, where regions of the foot arch above the substrate and the snail leaves a discontinuous mucus trail. Loping has been interpreted as a means of rapidly escaping predators. We found that the pulmonate Cornu aspersum moved using adhesive crawling on dry acrylic or glass substrates, but loped on dry concrete or wood. Loping snails did not move more rapidly than snails using adhesive crawling. Snails moving on concrete secreted a greater volume of pedal mucus per area of trail than those moving on acrylic; locomotion on concrete thus requires greater expenditure of mucus than does locomotion on acrylic. Because loping snails deposit a smaller area of mucus per distance traveled than do snails using adhesive crawling, loping may conserve mucus when moving on porous, absorbent substrates. Members of several other terrestrial pulmonate taxa can also lope on concrete, suggesting that this plasticity in gait is widespread among terrestrial snails.

Desorption isotherms of salted minced pork using K-lactate as a substitute for NaCl.

PubMed

Muñoz, I; Arnau, J; Costa-Corredor, A; Gou, P

2009-12-01

The aim of this study was to obtain and compare water desorption isotherms of ground meat containing NaCl (0.107kg NaCl/kg raw-meat dry matter) and/or K-lactate as NaCl substitute at two different levels of molar substitution (30% and 100%). A thin layer of salted ground meat was dried and sampled at pre-determined times. The moisture content of the samples and their water activities (a(w)) were measured at 5°C and 25°C. Results showed that ground meat with NaCl and/or different K-lactate contents had a similar water desorption isotherm for a(w) ranging from 0.7 to 1.0. Below 0.7, the water equilibrium content fell with small decreases in a(w) faster for meat with NaCl than for meat with K-lactate. K-lactate could reduce the excessive hardening at the surface of salted meat products. Experimental desorption isotherms were compared to those estimated using two approaches of the Ross equation. Models provided a good fit for the experimental data.

Scenedesmus sp. NJ-1 isolated from Antarctica: a suitable renewable lipid source for biodiesel production.

PubMed

Chen, Zhuo; Gong, Yangmin; Fang, Xiantao; Hu, Hanhua

2012-11-01

Microalgal lipids are promising alternative feedstocks for biodiesel production. Scenedesmus sp. NJ-1, an oil-rich freshwater microalga isolated from Antarctica, was identified to be a suitable candidate to produce biodiesel in this study. This strain could grow at temperatures ranging from 4 to 35 °C. With regular decrease in nitrate concentration in the medium, large quantities of triacylglycerols accumulated under batch culture conditions detected by thin layer chromatography and BODIPY 505/515 fluorescent staining. Scenedesmus sp. NJ-1 achieved the average biomass productivity of 0.105 g l⁻¹ d⁻¹ (dry weight) and nearly the highest lipid content (35 % of dry cell weight) was reached at day 28 in the batch culture. Neutral lipids accounted for 78 % of total lipids, and C18:1 (n-9), C16:0 were the major fatty acids in total lipids, composing 37 and 20 % of total fatty acids of Scenedesmus sp. NJ-1 grown for 36 days, respectively. These results suggested that Scenedesmus sp. NJ-1 was a good source of microalgal oils for biodiesel production.

Pressing of three-layer, dry-formed MDF with binderless hardboard faces

Treesearch

Otto Suchsland; George E. Woodson; Charles W. McMillin

1986-01-01

Severely cooked Masonite pulp was used as face material in three-layer experimental medium-density fiberboard (MDF). The core layer consisted of conventional MDF furnish with resin binder added. The faces were formed absolutely dry without additives of any kind. The three-layer mat was hot-pressed to overall densities ranging from 44 to 56 pcf. The faces had hardboard-...

Composite lamination method

NASA Technical Reports Server (NTRS)

Dickerson, G. E. (Inventor)

1977-01-01

A process was developed for preparing relatively thick composite laminate structure wherein thin layers of prepreg tapes are assembled, these thin layers are cut into strips that are partially cured, and stacked into the desired thickness with uncured prepreg disposed between each layer of strips. The formed laminate is finally cured and thereafter machined to the desired final dimensions.

A Step toward High-Energy Silicon-Based Thin Film Lithium Ion Batteries.

PubMed

Reyes Jiménez, Antonia; Klöpsch, Richard; Wagner, Ralf; Rodehorst, Uta C; Kolek, Martin; Nölle, Roman; Winter, Martin; Placke, Tobias

2017-05-23

The next generation of lithium ion batteries (LIBs) with increased energy density for large-scale applications, such as electric mobility, and also for small electronic devices, such as microbatteries and on-chip batteries, requires advanced electrode active materials with enhanced specific and volumetric capacities. In this regard, silicon as anode material has attracted much attention due to its high specific capacity. However, the enormous volume changes during lithiation/delithiation are still a main obstacle avoiding the broad commercial use of Si-based electrodes. In this work, Si-based thin film electrodes, prepared by magnetron sputtering, are studied. Herein, we present a sophisticated surface design and electrode structure modification by amorphous carbon layers to increase the mechanical integrity and, thus, the electrochemical performance. Therefore, the influence of amorphous C thin film layers, either deposited on top (C/Si) or incorporated between the amorphous Si thin film layers (Si/C/Si), was characterized according to their physical and electrochemical properties. The thin film electrodes were thoroughly studied by means of electrochemical impedance spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. We can show that the silicon thin film electrodes with an amorphous C layer showed a remarkably improved electrochemical performance in terms of capacity retention and Coulombic efficiency. The C layer is able to mitigate the mechanical stress during lithiation of the Si thin film by buffering the volume changes and to reduce the loss of active lithium during solid electrolyte interphase formation and cycling.

Effects of different wetting layers on the growth of smooth ultra-thin silver thin films

NASA Astrophysics Data System (ADS)

Ni, Chuan; Shah, Piyush; Sarangan, Andrew M.

2014-09-01

Ultrathin silver films (thickness below 10 nm) are of great interest as optical coatings on windows and plasmonic devices. However, producing these films has been a continuing challenge because of their tendency to form clusters or islands rather than smooth contiguous thin films. In this work we have studied the effect of Cu, Ge and ZnS as wetting layers (1.0 nm) to achieve ultrasmooth thin silver films. The silver films (5 nm) were grown by RF sputter deposition on silicon and glass substrates using a few monolayers of the different wetting materials. SEM imaging was used to characterize the surface properties such as island formation and roughness. Also the optical properties were measured to identify the optical impact of the different wetting layers. Finally, a multi-layer silver based structure is designed and fabricated, and its performance is evaluated. The comparison between the samples with different wetting layers show that the designs with wetting layers which have similar optical properties to silver produce the best overall performance. In the absence of a wetting layer, the measured optical spectra show a significant departure from the model predictions, which we attribute primarily to the formation of clusters.

Durable high strength cement concrete topping for asphalt roads

NASA Astrophysics Data System (ADS)

Vyrozhemskyi, Valerii; Krayushkina, Kateryna; Bidnenko, Nataliia

2017-09-01

Work on improving riding qualities of pavements by means of placing a thin cement layer with high roughness and strength properties on the existing asphalt pavement were conducted in Ukraine for the first time. Such pavement is called HPCM (High Performance Cementitious Material). This is a high-strength thin cement-layer pavement of 8-9 mm thickness reinforced with metal or polymer fiber of less than 5 mm length. Increased grip properties are caused by placement of stone material of 3-5 mm fraction on the concrete surface. As a result of the research, the preparation and placement technology of high-strength cement thin-layer pavement reinforced with fiber was developed to improve friction properties of existing asphalt pavements which ensures their roughness and durability. It must be emphasized that HPCM is a fundamentally new type of thin-layer pavement in which a rigid layer of 10 mm thickness is placed on a non-rigid base thereby improving riding qualities of asphalt pavement at any season of a year.

An investigation of material properties and tribological performance of magnetron sputtered thin film coatings

NASA Astrophysics Data System (ADS)

Singh, Harpal

This dissertation is divided into two categories based upon lubrication functionality and its application. The categories are: Dry film lubrication and Fluid film lubrication with thin film coatings. Thin film coatings examined in this work were deposited using closed field unbalanced magnetron sputtering and RF-DC coupled magnetron sputtering systems. In Dry/Solid film lubrication, the mechanical, structural and tribological properties of two Molybdenum disulphide (MoS2) based coatings are examined and evaluated. Among the two coatings, one coating is doped with Ti (Ti-MoS2) and the other is a combination of metal, lubricant and oxide (Sb2O3/Au - MoS2). These coatings are known to provide low friction in vacuum environments. The goal of this work was to evaluate friction and wear performance of MoS2 doped coatings in unidirectional and reciprocating sliding contact under different environmental conditions. Sliding contact results showed friction and wear dependence on temperature and humidity. The formation and removal of transfer films and the recrystallization and reorientation of basal layers on the steel counterface was observed as the mechanism for low friction. Structural analysis revealed a relationship between the microstructural properties and tribological performance. It was also observed that the addition of dopants (Ti, Au, Sb 2O3) improved the mechanical properties as compared to pure MoS2 coatings. Further, the rolling contact performance of the coatings was measured on a five ball on rod tribometer and a Thrust bearing tribometer under vacuum and air environments. The rolling contact experiments indicated that life of the rolling components depend on the amount of material present between the contacts. Fluid film lubrication with thin film coatings investigates the possibilities to improve the performance and durability of tribological components when oils and thin films are synergistically coupled. In this work, the ability of a Diamond Like Carbon coating to increase the durability of contacting surfaces under boundary lubrication were studied. The performance of highly hydrogenated Diamond Like Carbon (DLC) was evaluated in a mixed sliding and rolling contact. Experimental results show significant improvement in fatigue life of steel specimens after coating with a highly hydrogenated Diamond Like Carbon coating. The improved fatigue life is attributed to the coating microstructure and the mechanical properties.

[Assessment of lipid layer thickness of tear film in the diagnosis of dry-eye syndrome in children after the hematopoietic stem cell transplantation].

PubMed

Kurpińska, Małgorzata; Gorczyńska, Ewa; Owoc-Lempach, Joanna; Bernacka, Aleksandra; Misiuk-Hojło, Marta; Chybicka, Alicja

2011-01-01

Dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS) is recognized as the most frequent ocular complication after allogeneic stem cell transplantation (allo-SCT). KCS can appear either due to insufficient tear production or excessive tear evaporation, both resulting in tears hyperosmolarity that leads to ocular damage. The evaporation rate and better film stability is determined primarily by the status of the lipid layer. Observation and classification of tear film lipid layer interference patterns in normal and dry eyes in patients after allogeneic stem cell transplantation with a follow-up time of 6 months-5 years (median 26.54 months). Investigation of the relation between the lipid layer interference patterns in normal and dry eyes and the results of other dry eye examinations and complaints. Relation between DES and conditioning regimes, including total body irradiation and high-dose chemotherapy, immunosuppressive drugs, the time after allogeneic stem cell transplantation and chronic graft-versus-host disease. Precorneal tears lipid layer interference patterns, were examined in 114 eyes in treatment group with the Tearscope-plus. Patient with dry eye were identified on the basis of Schirmer test scores and/or tear breakup time, and positive lissamine and/or fluorescein staining. 42 of 114 eyes (36.8%) developed DES after allo-SCT A significant correlation between thickness of lipid layer and BUT, Schirmer test, lissamine green and fluorescein staining was found in the treatment group. A significant association was found between present chronic GVHD and DES in children. DES was not associated with TBI, corticosteroids, immunosuppressive drugs and the time in the present study. Tears lipid layer interference patterns are highly correlated with the diagnosis of DES. Tears lipid layer interference patterns ( noninvasive method), can be used to diagnose early DES in children after allo-SCT. Chronic GVHD play a major role in development of DES. dry eye syndrome, graft versus host disease, stem cell transplantation.

Uptake of Light Elements in Thin Metallic Films

NASA Astrophysics Data System (ADS)

Markwitz, Andreas; Waldschmidt, Mathias

Ion beam analysis was used to investigate the influence of substrate temperature on the inclusion of impurities during the deposition process of thin metallic single and double layers. Thin layers of gold and aluminium were deposited at different temperatures onto thin copper layers evaporated on silicon wafer substrates. The uptake of oxygen in the layers was measured using the highly sensitive non-resonant reaction 16O(d,p)170O at 920 keV. Nuclear reaction analysis was also used to probe for carbon and nitrogen with a limit of detection better than 20 ppm. Hydrogen depth profiles were measured using elastic recoil detection on the nanometer scale. Rutherford backscattering spectroscopy was used to determine the depth profiles of the metallic layers and to study diffusion processes. The combined ion beam analyses revealed an uptake of oxygen in the layers depending on the different metallic cap layers and the deposition temperature. Lowest oxygen values were measured for the Au/Cu layers, whereas the highest amount of oxygen was measured in Al/Cu layers deposited at 300°C. It was also found that with single copper layers produced at various temperatures, oxygen contamination occurred during the evaporation process and not afterwards, for example, as a consequence of the storage of the films under normal conditions for several days. Hydrogen, carbon, and nitrogen were found as impurities in the single and double layered metallic films, a finding that is in agreement with the measured oxidation behaviour of the metallic films.

Method of forming ultra thin film devices by vacuum arc vapor deposition

NASA Technical Reports Server (NTRS)

Schramm, Harry F. (Inventor)

2005-01-01

A method for providing an ultra thin electrical circuit integral with a portion of a surface of an object, including using a focal Vacuum Arc Vapor Deposition device having a chamber, a nozzle and a nozzle seal, depressing the nozzle seal against the portion of the object surface to create an airtight compartment in the chamber and depositing one or more ultra thin film layer(s) only on the portion of the surface of the object, the layers being of distinct patterns such that they form the circuit.

Non-destructive evaluation of nano-sized structure of thin film devices by using small angle neutron scattering.

PubMed

Shin, E J; Seong, B S; Choi, Y; Lee, J K

2011-01-01

Nano-sized multi-layers copper-doped SrZrO3, platinum (Pt) and silicon oxide (SiO2) on silicon substrates were prepared by dense plasma focus (DPF) device with the high purity copper anode tip and analyzed by using small angle neutron scattering (SANS) to establish a reliable method for the non-destructive evaluation of the under-layer structure. Thin film was well formed at the time-to-dip of 5 microsec with stable plasma of DPF. Several smooth intensity peaks were periodically observed when neutron beam penetrates the thin film with multi-layers perpendicularly. The platinum layer is dominant to intensity peaks, where the copper-doped SrZnO3 layer next to the platinum layer causes peak broadening. The silicon oxide layer has less effect on the SANS spectra due to its relative thick thickness. The SANS spectra shows thicknesses of platinum and copper-doped SrZnO3 layers as 53 and 25 nm, respectively, which are well agreement with microstructure observation.

Layer-by-layer deposition of nanostructured CsPbBr3 perovskite thin films

NASA Astrophysics Data System (ADS)

Reshetnikova, A. A.; Matyushkin, L. B.; Andronov, A. A.; Sokolov, V. S.; Aleksandrova, O. A.; Moshnikov, V. A.

2017-11-01

Layer-by-layer deposition of nanostructured perovskites cesium lead halide thin films is described. The method of deposition is based on alternate immersion of the substrate in the precursor solutions or colloidal solution of nanocrystals and methyl acetate/lead nitrate solution using the device for deposition of films by SILAR and dip-coating techniques. An example of obtaining a photosensitive structure based on nanostructures of ZnO nanowires and layers of CsBbBr3 nanocrystals is also shown.

Silicon superlattices. 2: Si-Ge heterostructures and MOS systems

NASA Technical Reports Server (NTRS)

Moriarty, J. A.

1983-01-01

Five main areas were examined: (1) the valence-and conduction-band-edge electronic structure of the thin layer ( 11 A) silicon-superlattice systems; (2) extension of thin-layer calculations to layers of thickness 11 A, where most potential experimental interest lies; (3) the electronic structure of thicker-layer (11 to 110 A) silicon superlattices; (4) preliminary calculations of impurity-scattering-limited electron mobility in the thicker-layer superlattices; and (5) production of the fine metal lines that would be required to produce on MOS superlattice.

Epitaxial thinning process

NASA Technical Reports Server (NTRS)

Siegel, C. M. (Inventor)

1984-01-01

A method is described for thinning an epitaxial layer of a wafer that is to be used in producing diodes having a specified breakdown voltage and which also facilitates the thinning process. Current is passed through the epitaxial layer, by connecting a current source between the substrate of the wafer and an electrolyte in which the wafer is immersed. When the wafer is initially immersed, the voltage across the wafer initially drops and then rises at a steep rate. When light is applied to the wafer the voltage drops, and when the light is interrupted the voltage rises again. These changes in voltage, each indicate the breakdown voltage of a Schottky diode that could be prepared from the wafer at that time. The epitaxial layer is thinned by continuing to apply current through the wafer while it is immersed and light is applied, to form an oxide film and when the oxide film is thick the wafer can then be cleaned of oxide and the testing and thinning continued. Uninterrupted thinning can be achieved by first forming an oxide film, and then using an electrolyte that dissolves the oxide about as fast as it is being formed, to limit the thickness of the oxide layer.

Changes in the phenolic acid content during commercial dry-grind processing of corn to ethanol and DDGS

USDA-ARS?s Scientific Manuscript database

Nine fractions (ground corn-1, cooked slurry-2, liquefied slurry-3, fermented mash-4, whole stillage-5, thin stillage-6, condensed distillers soluble (CDS)-7, distillers wet grains (DWG)-8, and distillers dried grains with solubles (DDGS)-9) were collected from three commercial dry-grind bioethanol ...

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube-silicon solar cells.

PubMed

Stolz, Benedikt W; Tune, Daniel D; Flavel, Benjamin S

2016-01-01

Recent results in the field of carbon nanotube-silicon solar cells have suggested that the best performance is obtained when the nanotube film provides good coverage of the silicon surface and when the nanotubes in the film are aligned parallel to the surface. The recently developed process of dry shear aligning - in which shear force is applied to the surface of carbon nanotube thin films in the dry state, has been shown to yield nanotube films that are very flat and in which the surface nanotubes are very well aligned in the direction of shear. It is thus reasonable to expect that nanotube films subjected to dry shear aligning should outperform otherwise identical films formed by other processes. In this work, the fabrication and characterisation of carbon nanotube-silicon solar cells using such films is reported, and the photovoltaic performance of devices produced with and without dry shear aligning is compared.

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube–silicon solar cells

PubMed Central

Stolz, Benedikt W; Tune, Daniel D

2016-01-01

Summary Recent results in the field of carbon nanotube–silicon solar cells have suggested that the best performance is obtained when the nanotube film provides good coverage of the silicon surface and when the nanotubes in the film are aligned parallel to the surface. The recently developed process of dry shear aligning – in which shear force is applied to the surface of carbon nanotube thin films in the dry state, has been shown to yield nanotube films that are very flat and in which the surface nanotubes are very well aligned in the direction of shear. It is thus reasonable to expect that nanotube films subjected to dry shear aligning should outperform otherwise identical films formed by other processes. In this work, the fabrication and characterisation of carbon nanotube–silicon solar cells using such films is reported, and the photovoltaic performance of devices produced with and without dry shear aligning is compared. PMID:27826524

Electrochemical planarization

DOEpatents

Bernhardt, A.F.; Contolini, R.J.

1993-10-26

In a process for fabricating planarized thin film metal interconnects for integrated circuit structures, a planarized metal layer is etched back to the underlying dielectric layer by electropolishing, ion milling or other procedure. Electropolishing reduces processing time from hours to minutes and allows batch processing of multiple wafers. The etched back planarized thin film interconnect is flush with the dielectric layer. 12 figures.

Use of screenings to produce HMA mixtures

DOT National Transportation Integrated Search

2002-10-01

Thin-lift hot mix asphalt (HMA) layers are utilized in almost every maintenance and rehabilitation application. These mix types require smaller maximum particle sizes than most conventional HMA surface layers. Although the primary functions of thin-l...

[Ascending one-dimensional thin layer chromatography in specific blood diagnosis (author's transl)].

PubMed

Bernardelli, B; Masotti, G

1976-01-01

A brief review of the literature on chromatography in forensic haematology is followed by a report of the results obtained by using ascending one-dimensional thin layer chromatography in specific blood diagnosis.

Evaluation of manometric temperature measurement, a process analytical technology tool for freeze-drying: part II measurement of dry-layer resistance.

PubMed

Tang, Xiaolin Charlie; Nail, Steven L; Pikal, Michael J

2006-01-01

The purpose of this work was to study the factors that may cause systematic errors in the manometric temperature measurement (MTM) procedure used to determine product dry-layer resistance to vapor flow. Product temperature and dry-layer resistance were obtained using MTM software installed on a laboratory freeze-dryer. The MTM resistance values were compared with the resistance values obtained using the "vial method." The product dry-layer resistances obtained by MTM, assuming fixed temperature difference (DeltaT; 2 degrees C), were lower than the actual values, especially when the product temperatures and sublimation rates were low, but with DeltaT determined from the pressure rise data, more accurate results were obtained. MTM resistance values were generally lower than the values obtained with the vial method, particularly whenever freeze-drying was conducted under conditions that produced large variations in product temperature (ie, low shelf temperature, low chamber pressure, and without thermal shields). In an experiment designed to magnify temperature heterogeneity, MTM resistance values were much lower than the simple average of the product resistances. However, in experiments where product temperatures were homogenous, good agreement between MTM and "vial-method" resistances was obtained. The reason for the low MTM resistance problem is the fast vapor pressure rise from a few "warm" edge vials or vials with low resistance. With proper use of thermal shields, and the evaluation of DeltaT from the data, MTM resistance data are accurate. Thus, the MTM method for determining dry-layer resistance is a useful tool for freeze-drying process analytical technology.

Flat-lying semiconductor-insulator interfacial layer in DNTT thin films.

PubMed

Jung, Min-Cherl; Leyden, Matthew R; Nikiforov, Gueorgui O; Lee, Michael V; Lee, Han-Koo; Shin, Tae Joo; Takimiya, Kazuo; Qi, Yabing

2015-01-28

The molecular order of organic semiconductors at the gate dielectric is the most critical factor determining carrier mobility in thin film transistors since the conducting channel forms at the dielectric interface. Despite its fundamental importance, this semiconductor-insulator interface is not well understood, primarily because it is buried within the device. We fabricated dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) thin film transistors by thermal evaporation in vacuum onto substrates held at different temperatures and systematically correlated the extracted charge mobility to the crystal grain size and crystal orientation. As a result, we identify a molecular layer of flat-lying DNTT molecules at the semiconductor-insulator interface. It is likely that such a layer might form in other material systems as well, and could be one of the factors reducing charge transport. Controlling this interfacial flat-lying layer may raise the ultimate possible device performance for thin film devices.

Bias of shear wave elasticity measurements in thin layer samples and a simple correction strategy.

PubMed

Mo, Jianqiang; Xu, Hao; Qiang, Bo; Giambini, Hugo; Kinnick, Randall; An, Kai-Nan; Chen, Shigao; Luo, Zongping

2016-01-01

Shear wave elastography (SWE) is an emerging technique for measuring biological tissue stiffness. However, the application of SWE in thin layer tissues is limited by bias due to the influence of geometry on measured shear wave speed. In this study, we investigated the bias of Young's modulus measured by SWE in thin layer gelatin-agar phantoms, and compared the result with finite element method and Lamb wave model simulation. The result indicated that the Young's modulus measured by SWE decreased continuously when the sample thickness decreased, and this effect was more significant for smaller thickness. We proposed a new empirical formula which can conveniently correct the bias without the need of using complicated mathematical modeling. In summary, we confirmed the nonlinear relation between thickness and Young's modulus measured by SWE in thin layer samples, and offered a simple and practical correction strategy which is convenient for clinicians to use.

AES study on the chemical composition of ferroelectric BaTiO3 thin films RF sputter-deposited on silicon

NASA Technical Reports Server (NTRS)

Dharmadhikari, V. S.; Grannemann, W. W.

1983-01-01

AES depth profiling data are presented for thin films of BaTiO3 deposited on silicon by RF sputtering. By profiling the sputtered BaTiO3/silicon structures, it was possible to study the chemical composition and the interface characteristics of thin films deposited on silicon at different substrate temperatures. All the films showed that external surface layers were present, up to a few tens of angstroms thick, the chemical composition of which differed from that of the main layer. The main layer had stable composition, whereas the intermediate film-substrate interface consisted of reduced TiO(2-x) oxides. The thickness of this intermediate layer was a function of substrate temperature. All the films showed an excess of barium at the interface. These results are important in the context of ferroelectric phenomena observed in BaTiO3 thin films.

Impact of bimetal electrodes on dielectric properties of TiO2 and Al-doped TiO2 films.

PubMed

Kim, Seong Keun; Han, Sora; Jeon, Woojin; Yoon, Jung Ho; Han, Jeong Hwan; Lee, Woongkyu; Hwang, Cheol Seong

2012-09-26

Rutile structured Al-doped TiO(2) (ATO) and TiO(2) films were grown on bimetal electrodes (thin Ru/thick TiN, Pt, and Ir) for high-performance capacitors. The work function of the top Ru layer decreased on TiN and increased on Pt and Ir when it was thinner than ~2 nm, suggesting that the lower metal within the electrodes influences the work function of the very thin Ru layer. The use of the lower electrode with a high work function for bottom electrode eventually improves the leakage current properties of the capacitor at a very thin Ru top layer (≤2 nm) because of the increased Schottky barrier height at the interface between the dielectric and the bottom electrode. The thin Ru layer was necessary to achieve the rutile structured ATO and TiO(2) dielectric films.

Fuel cell with interdigitated porous flow-field

DOEpatents

Wilson, Mahlon S.

1997-01-01

A polymer electrolyte membrane (PEM) fuel cell is formed with an improved system for distributing gaseous reactants to the membrane surface. A PEM fuel cell has an ionic transport membrane with opposed catalytic surfaces formed thereon and separates gaseous reactants that undergo reactions at the catalytic surfaces of the membrane. The fuel cell may also include a thin gas diffusion layer having first and second sides with a first side contacting at least one of the catalytic surfaces. A macroporous flow-field with interdigitated inlet and outlet reactant channels contacts the second side of the thin gas diffusion layer for distributing one of the gaseous reactants over the thin gas diffusion layer for transport to an adjacent one of the catalytic surfaces of the membrane. The porous flow field may be formed from a hydrophilic material and provides uniform support across the backside of the electrode assembly to facilitate the use of thin backing layers.

Fuel cell with interdigitated porous flow-field

DOEpatents

Wilson, M.S.

1997-06-24

A polymer electrolyte membrane (PEM) fuel cell is formed with an improved system for distributing gaseous reactants to the membrane surface. A PEM fuel cell has an ionic transport membrane with opposed catalytic surfaces formed thereon and separates gaseous reactants that undergo reactions at the catalytic surfaces of the membrane. The fuel cell may also include a thin gas diffusion layer having first and second sides with a first side contacting at least one of the catalytic surfaces. A macroporous flow-field with interdigitated inlet and outlet reactant channels contacts the second side of the thin gas diffusion layer for distributing one of the gaseous reactants over the thin gas diffusion layer for transport to an adjacent one of the catalytic surfaces of the membrane. The porous flow field may be formed from a hydrophilic material and provides uniform support across the backside of the electrode assembly to facilitate the use of thin backing layers. 9 figs.

Electrical contacts to thin layers of Bi2Sr2CaCu2O8+δ

NASA Astrophysics Data System (ADS)

Suzuki, Shota; Taniguchi, Hiroki; Kawakami, Tsukasa; Cosset-Cheneau, Maxen; Arakawa, Tomonori; Miyasaka, Shigeki; Tajima, Setsuko; Niimi, Yasuhiro; Kobayashi, Kensuke

2018-05-01

Thin layers of Bi2Sr2CaCu2O8+δ (Bi2212) were fabricated using the mechanical exfoliation technique. Good electrical contacts to the thin Bi2212 films with low contact resistance were realized by depositing Ag and Au electrodes onto the Bi2212 films and annealing them with an oxygen flow at 350 °C for 30 min. We observed cross-section images of the Bi2212 thin film device using a transmission electron microscope to characterize the diffusion of Ag and Au atoms into the Bi2212 thin film.

Effects of dry period length and concentrate protein content in late lactation on body condition score change and subsequent lactation performance of thin high genetic merit dairy cows.

PubMed

Dale, A J; Purcell, P J; Wylie, A R G; Gordon, A W; Ferris, C P

2017-03-01

Improving body condition score of thin cows in late lactation is necessary, because cows that are thin at drying off exhibit decreased fertility postpartum and are at increased risk of disease and of being culled in the subsequent lactation. Offering a diet low in crude protein (CP) content in late lactation may help to improve body condition score (BCS) at drying off, whereas imposing an extended dry period (EDP) has been advocated as another way to increase BCS at calving. To test these hypotheses, 65 thin cows (mean BCS 2.25 at 14 wk precalving) were managed on 1 of 3 treatments between 13 and 9 wk prepartum: normal protein control {NP; grass silage + 5 kg/d of a normal protein concentrate [228 g of CP/kg of dry matter (DM)]}, low protein [LP; grass silage + 5 kg/d of a low-protein concentrate (153 g of CP/kg of DM)], or EDP (cows dried off at 13 wk precalving and offered a grass silage-only diet). Both NP and LP cows were dried off at wk 8 prepartum, after which all cows were offered a grass silage-only diet until calving. After calving, all cows were offered a common diet (supplying 11.1 kg of concentrate DM/cow per day) for 19 wk. Between 13 and 9 wk prepartum, LP cows had lower DM intake, milk yield, and body weight than NP cows. Whereas EDP cows had lower serum β-hydroxybutyrate and fatty acid concentrations than those of NP cows, BCS at wk 9 prepartum did not differ between treatments. Cows on the LP treatment continued to have lower DMI and BW than those of NP and EDP cows between 8 wk prepartum and calving, but only EDP cows had a higher BCS at calving. Treatment did not affect calving difficulty score or calf birth weight. Although all cows were offered a common diet postpartum, cows on the LP treatment had lower DM intake and milk fat + plus protein yield than cows on any other treatment during the 19-wk period postpartum, but we found no differences in any postpartum indicator of body tissue reserves. The treatments imposed from wk 13 to 9 prepartum had no effect on any fertility or health parameters examined postpartum. Extending the dry period for thin cows improved their BCS at calving but did not allow these cows to achieve the target BCS of 2.75, and we found no beneficial effects of this treatment on cow performance postpartum. Offering a lower-protein diet to thin cows in late lactation did not improve BCS at calving above that of cows on a normal protein diet, but had unexplained long-term negative effects on cow performance. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Precise Control of the Number of Layers of Graphene by Picosecond Laser Thinning.

PubMed

Lin, Zhe; Ye, Xiaohui; Han, Jinpeng; Chen, Qiao; Fan, Peixun; Zhang, Hongjun; Xie, Dan; Zhu, Hongwei; Zhong, Minlin

2015-06-26

The properties of graphene can vary as a function of the number of layers (NOL). Controlling the NOL in large area graphene is still challenging. In this work, we demonstrate a picosecond (ps) laser thinning removal of graphene layers from multi-layered graphene to obtain desired NOL when appropriate pulse threshold energy is adopted. The thinning process is conducted in atmosphere without any coating and it is applicable for graphene films on arbitrary substrates. This method provides many advantages such as one-step process, non-contact operation, substrate and environment-friendly, and patternable, which will enable its potential applications in the manufacturing of graphene-based electronic devices.

Precise Control of the Number of Layers of Graphene by Picosecond Laser Thinning

NASA Astrophysics Data System (ADS)

Lin, Zhe; Ye, Xiaohui; Han, Jinpeng; Chen, Qiao; Fan, Peixun; Zhang, Hongjun; Xie, Dan; Zhu, Hongwei; Zhong, Minlin

2015-06-01

The properties of graphene can vary as a function of the number of layers (NOL). Controlling the NOL in large area graphene is still challenging. In this work, we demonstrate a picosecond (ps) laser thinning removal of graphene layers from multi-layered graphene to obtain desired NOL when appropriate pulse threshold energy is adopted. The thinning process is conducted in atmosphere without any coating and it is applicable for graphene films on arbitrary substrates. This method provides many advantages such as one-step process, non-contact operation, substrate and environment-friendly, and patternable, which will enable its potential applications in the manufacturing of graphene-based electronic devices.