Novel technique for fabrication of multi-layered microcoils in microelectromechanical systems (MEMS) applications

NASA Astrophysics Data System (ADS)

Chang, Hung-Pin; Qian, Jiangyuan; Bachman, Mark; Congdon, Philip; Li, Guann-pyng

2002-07-01

A novel planarization technique, compressive molding planarization (CMP) is developed for implementation of a multi-layered micro coil device. Applying CMP and other micromachining techniques, a multi-layered micro coil device has been designed and fabricated, and its use in the magnetic micro actuators for hard disk drive applications has been demonstrated, showing that it can produce milli-Newton of magnetic force suitable for driving a micro actuator. The novel CMP technique can be equally applicable in other MEMS devices fabrication to ease the process integration for the complicated structure.

Design of a thermal waist-pad

NASA Astrophysics Data System (ADS)

Kursun Bahadir, S.; Sahin, U. K.; Acikgoz Tufan, H.

2017-10-01

The objective of the current study is designing a thermal waist-pad for people who have backaches with a sandwich-like multi-layered structure. Two model is developed; one is three-layered and second is five-layered with waterproof woven outer layer fabric, Thermolite® knitted fabric (for five-layered structures), wool knitted, polyester nonwoven fabric, polypropylene nonwoven fabric and viscose nonwoven fabric for mid-layer. 10 different structures are designed and produced. All samples are tested for thermal comfort properties of waist-pad. Multi-layer structures were tested, and according to their thermal performance and thermal comfort criteria, all results are evaluated for identifying the best product. These three factors are examined by analysis of thermal conductivity, thermal resistance, thermal absorptivity, relative water vapour/air permeability, water absorption. Highest thermal resistance test result, 150,42 mK/Wm2, is achieved in five-layered sandwich structure with waterproof fabric, Thermolite® fabric, wool based knitted fabric, Thermolite® fabric and waterproof fabric, respectively. Thermal conductivity result of this structure is 46,2 mW/mK, which is one of the lowest results among the alternative structures. Structures with Thermolite® fabric show higher thermal comfort when compared to others.

Three-dimensional bioprinting of cell-laden constructs with polycaprolactone protective layers for using various thermoplastic polymers.

PubMed

Kim, Byoung Soo; Jang, Jinah; Chae, Suhun; Gao, Ge; Kong, Jeong-Sik; Ahn, Minjun; Cho, Dong-Woo

2016-08-22

Three-dimensional (3D) cell-printed constructs have been recognized as promising biological substitutes for tissue/organ regeneration. They provide tailored physical properties and biological cues via multi-material printing process. In particular, hybrid bioprinting, enabling to use biodegradable synthetic polymers as framework, has been an attractive method to support weak hydrogels. The constructs with controlled architecture and high shape fidelity were fabricated through this method, depositing spatial arrangement of multi-cell types into microscale constructs. Among biodegradable synthetic polymers, polycaprolactone (PCL) has been commonly chosen in fabrication of cell-printed constructs because of its low melting temperature of 60 °C to be dispensed with extrusion-based bioprinting system. However, in addition to PCL, various synthetic polymers have been widely applied for tissue regeneration. These polymers have distinctive characteristics essential for tissue/organ regeneration. Nevertheless, it is difficult to use some polymers, such as poly (lactic-co-glycolic acid) (PLGA) and polylactic acid (PLA) with 3D bioprinting technology because of their high melting temperature to be dispensed, which can result in thermal damage to the cells in the printed constructs during the fabrication process. We present a novel bioprinting method to use various synthetic polymers in fabrication of cell-printed constructs. PCL was introduced as a protective layer to prevent thermal damage caused by high temperature of polymers during fabrication. Remarkable improvement in cellular activities in the printed constructs with PCL layers was observed compared with the construct without PCL. This bioprinting method can be applied to fabricate more tissue-like constructs through the use of various biomaterials.

Two Dimensional (2D) P-Aramid Dry Multi-Layered Woven Fabrics Deformational Behaviour for Technical Applications

NASA Astrophysics Data System (ADS)

Abtew, M. A.; Loghin, C.; Cristian, I.; Boussu, F.; Bruniaux, P.; Chen, Y.; Wang, L.

2018-06-01

In today’s scenario for the various technical applications, from composites to body armour, the material mouldability along with its mechanical property become very important. In the present study, two dimensional (2D) woven fabrics made of para-aramid high performance fibres in multi-layer dry structure were used for investigating different forming characteristics. The different layers were arranged with 0°/90° orientation for deep drawing formability test to analyse the effect of number of layers and blank-holder pressure (BHP) during the test. Specific preforming device with low speed forming process and predefined hemispherical shape of punch has been applied. Using fine photographic analysis, some important 2D multi-layer fabrics forming characteristics i.e., material drawing-in, surface shear angle etc. from the imposed deformation have been observed, measured and analysed for better understanding and co MPa rison. The result revealed that the mouldability behaviour of the multi-layered dry textile fabric preforms is directional, and closely dependent on blank-holding pressure and number of layers. This indicates both parameters should be carefully considered while material deformation to avoid the formation of wrinkling and maintain other mechanical properties on final application.

Design and fabrication of a multi-layered solid dynamic phantom: validation platform on methods for reducing scalp-hemodynamic effect from fNIRS signal

NASA Astrophysics Data System (ADS)

Kawaguchi, Hiroshi; Tanikawa, Yukari; Yamada, Toru

2017-02-01

Scalp hemodynamics contaminates the signals from functional near-infrared spectroscopy (fNIRS). Numerous methods have been proposed to reduce this contamination, but no golden standard has yet been established. Here we constructed a multi-layered solid phantom to experimentally validate such methods. This phantom comprises four layers corresponding to epidermides, dermis/skull (upper dynamic layer), cerebrospinal fluid and brain (lower dynamic layer) and the thicknesses of these layers were 0.3, 10, 1, and 50 mm, respectively. The epidermides and cerebrospinal fluid layers were made of polystyrene and an acrylic board, respectively. Both of these dynamic layers were made of epoxy resin. An infrared dye and titanium dioxide were mixed to match their absorption and reduced scattering coefficients (μa and μs', respectively) with those of biological tissues. The bases of both upper and lower dynamic layers have a slot for laterally sliding a bar that holds an absorber piece. This bar was laterally moved using a programmable stepping motor. The optical properties of dynamic layers were estimated based on the transmittance and reflectance using the Monte Carlo look-up table method. The estimated coefficients for lower and upper dynamic layers approximately coincided with those for biological tissues. We confirmed that the preliminary fNIRS measurement using the fabricated phantom showed that the signals from the brain layer were recovered if those from the dermis layer were completely removed from their mixture, indicating that the phantom is useful for evaluating methods for reducing the contamination of the signals from the scalp.

Fabrication of hybrid molecular devices using multi-layer graphene break junctions.

PubMed

Island, J O; Holovchenko, A; Koole, M; Alkemade, P F A; Menelaou, M; Aliaga-Alcalde, N; Burzurí, E; van der Zant, H S J

2014-11-26

We report on the fabrication of hybrid molecular devices employing multi-layer graphene (MLG) flakes which are patterned with a constriction using a helium ion microscope or an oxygen plasma etch. The patterning step allows for the localization of a few-nanometer gap, created by electroburning, that can host single molecules or molecular ensembles. By controlling the width of the sculpted constriction, we regulate the critical power at which the electroburning process begins. We estimate the flake temperature given the critical power and find that at low powers it is possible to electroburn MLG with superconducting contacts in close proximity. Finally, we demonstrate the fabrication of hybrid devices with superconducting contacts and anthracene-functionalized copper curcuminoid molecules. This method is extendable to spintronic devices with ferromagnetic contacts and a first step towards molecular integrated circuits.

Fabrication of hybrid molecular devices using multi-layer graphene break junctions

NASA Astrophysics Data System (ADS)

Island, J. O.; Holovchenko, A.; Koole, M.; Alkemade, P. F. A.; Menelaou, M.; Aliaga-Alcalde, N.; Burzurí, E.; van der Zant, H. S. J.

2014-11-01

We report on the fabrication of hybrid molecular devices employing multi-layer graphene (MLG) flakes which are patterned with a constriction using a helium ion microscope or an oxygen plasma etch. The patterning step allows for the localization of a few-nanometer gap, created by electroburning, that can host single molecules or molecular ensembles. By controlling the width of the sculpted constriction, we regulate the critical power at which the electroburning process begins. We estimate the flake temperature given the critical power and find that at low powers it is possible to electroburn MLG with superconducting contacts in close proximity. Finally, we demonstrate the fabrication of hybrid devices with superconducting contacts and anthracene-functionalized copper curcuminoid molecules. This method is extendable to spintronic devices with ferromagnetic contacts and a first step towards molecular integrated circuits.

The usage of phase change materials in fire fighter protective clothing: its effect on thermal protection

NASA Astrophysics Data System (ADS)

Zhao, Mengmeng

2017-12-01

The thermal protective performance of the fire fighter protective clothing is of vital importance for fire fighters. In the study fabrics treated by phase change materials (PCMs) were applied in the multi-layered fabrics of the fire fighter protective clothing ensemble. The PCM fabrics were placed at the different layers of the clothing and their thermal protective performance were measured by a TPP tester. Results show that with the application of the PCM fabrics the thermal protection of the multi-layered fabrics was greatly increased. The time to reach a second degree burn was largely reduced. The location of the PCM fabrics at the different layers did not affect much on the thermal protective performance. The higher amount of the PCM adds on, the higher thermal protection was brought. The fabrics with PCMs of a higher melting temperature could contribute to higher thermal protection.

Nano-fabricated perpendicular magnetic anisotropy electrodes for lateral spin valves and observation of Nernst-Ettingshausen related signals

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

Chejanovsky, N.; Sharoni, A., E-mail: amos.sharoni@biu.ac.il

2014-08-21

Lateral spin valves (LSVs) are efficient structures for characterizing spin currents in spintronics devices. Most LSVs are based on ferromagnetic (FM) electrodes for spin-injection and detection. While there are advantages for using perpendicular magnetic anisotropy (PMA) FM, e.g., stability to nano-scaling, these have almost not been studied. This is mainly due to difficulties in fabricating PMA FMs in a lateral geometry. We present here an efficient method, based on ion-milling through an AlN mask, for fabrication of LSVs with multi-layered PMA FMs such as Co/Pd and Co/Ni. We demonstrate, using standard permalloy FMs, that the method enables efficient spin injection.more » We show the multi-layer electrodes retain their PMA properties as well as spin injection and detection in PMA LSVs. In addition, we find a large asymmetric voltage signal which increases with current. We attribute this to a Nernst-Ettingshausen effect caused by local Joule heating and the perpendicular magnetic easy axis.« less

A novel method of fabricating laminated silicone stack actuators with pre-strained dielectric layers

NASA Astrophysics Data System (ADS)

Hinitt, Andrew D.; Conn, Andrew T.

2014-03-01

In recent studies, stack based Dielectric Elastomer Actuators (DEAs) have been successfully used in haptic feedback and sensing applications. However, limitations in the fabrication method, and materials used to con- struct stack actuators constrain their force and displacement output per unit volume. This paper focuses on a fabrication process enabling a stacked elastomer actuator to withstand the high tensile forces needed for high power applications, such as mimetics for mammalian muscle contraction (i.e prostheses), whilst requiring low voltage for thickness-mode contractile actuation. Spun elastomer layers are bonded together in a pre-strained state using a conductive adhesive filler, forming a Laminated Inter-Penetrating Network (L-IPN) with repeatable and uniform electrode thickness. The resulting structure utilises the stored strain energy of the dielectric elas- tomer to compress the cured electrode composite material. The method is used to fabricate an L-IPN example, which demonstrated that the bonded L-IPN has high tensile strength normal to the lamination. Additionally, the uniformity and retained dielectric layer pre-strain of the L-IPN are confirmed. The described method is envisaged to be used in a semi-automated assembly of large-scale multi-layer stacks of pre-strained dielectric layers possessing a tensile strength in the range generated by mammalian muscle.

Magnet-assisted device-level alignment for the fabrication of membrane-sandwiched polydimethylsiloxane microfluidic devices

NASA Astrophysics Data System (ADS)

Lu, J.-C.; Liao, W.-H.; Tung, Y.-C.

2012-07-01

Polydimethylsiloxane (PDMS) microfluidic device is one of the most essential techniques that advance microfluidics research in recent decades. PDMS is broadly exploited to construct microfluidic devices due to its unique and advantageous material properties. To realize more functionalities, PDMS microfluidic devices with multi-layer architectures, especially those with sandwiched membranes, have been developed for various applications. However, existing alignment methods for device fabrication are mainly based on manual observations, which are time consuming, inaccurate and inconsistent. This paper develops a magnet-assisted alignment method to enhance device-level alignment accuracy and precision without complicated fabrication processes. In the developed alignment method, magnets are embedded into PDMS layers at the corners of the device. The paired magnets are arranged in symmetric positions at each PDMS layer, and the magnetic attraction force automatically pulls the PDMS layers into the aligned position during assembly. This paper also applies the method to construct a practical microfluidic device, a tunable chaotic micromixer. The results demonstrate the successful operation of the device without failure, which suggests the accurate alignment and reliable bonding achieved by the method. Consequently, the fabrication method developed in this paper is promising to be exploited to construct various membrane-sandwiched PDMS microfluidic devices with more integrated functionalities to advance microfluidics research.

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.

Single-crystal micromachining using multiple fusion-bonded layers

NASA Astrophysics Data System (ADS)

Brown, Alan; O'Neill, Garry; Blackstone, Scott C.

2000-08-01

Multi-layer structures have been fabricated using Fusion bonding. The paper shows void free layers of between 2 and 100 microns that have been bonded to form multi-layer structures. Silicon layers have been bonded both with and without interfacial oxide layers.

Preparation and characterization of multi-layer biodegradable nanofibers by coaxial electrospinning and their potential for tissue engineering

NASA Astrophysics Data System (ADS)

Liu, Wenwen

As an evolution of conventional electrospinning, coaxial electrospinning became popular soon after its debut as a novel way to develop nanofibers with special structures, such as core-shell and hollow interior. In recent years, there has been an increasing interest in a modified coaxial electrospinning, tri-layer coaxial electrospinning, to develop more complex structures, such as multi-layer and nanowire-in-microtube. Previous studies have primarily concentrated on the fabrication of tri-layered inorganic fibers while studies on tri-layered coaxial polymeric fibers has not been reported until very recently. Our research focuses on the fabrication of core-shell and tri-layer structured biodegradable polymeric nanofibers with coaxial electrospinning. Different characterization methods have been applied to observe the internal structure in single nanofibers and the potential application of tri-layer coaxial electrospinning has been discussed. The material system consists of biodegradable natural polymer gelatin, synthetic polymers poly (epsilon-caprolactone) (PCL) and poly (lactic-co-glycolic acid) (PLGA). A uniquely designed three-needle concentric spinneret is developed to perform tri-layer coaxial electrospinning. Different kinds of core-shell structured nanofibers, including gelatin/PCL, PCL/gelatin, gelatin/PLGA and PCL/PLGA, have been fabricated with a customized coaxial electrospinning apparatus. Two kinds of tri-layer coaxial nanofibers, two-component ABA structured gelatin/PCL/gelatin biodegradable nanofibers and tri-component ABC structured gelatin/PCL/PLGA biodegradable nanofibers, have been developed with the customized three needle coaxial electrospinning setup. The core-shell and tri-layered structures of electrospun nanofibers have been characterized by several commonly used techniques, such as laser scanning confocal microscopy (LSCM) and transmission electron microscopy (TEM). Besides the conventional methods, other newer techniques, including focused ion beam-scanning electron microscopy (FIB-SEM), super-resolution structured illumination microscopy (SR-SIM) and nanoscale-infrared spectroscopy (nano-IR), have been explored to investigate the internal structure in singles fibers. Additionally, the potential application of coaxial electrospinning in the fabrication of bioactive scaffolds for tissue engineering has been studied. Different kinds of coaxial nanofibers were fabricated and studied to determine the potential for BSA and growth factor release and some preliminary results were obtained.

Multi-material poly(lactic acid) scaffold fabricated via fused deposition modeling and direct hydroxyapatite injection as spacers in laminoplasty

NASA Astrophysics Data System (ADS)

Syuhada, Ghifari; Ramahdita, Ghiska; Rahyussalim, A. J.; Whulanza, Yudan

2018-02-01

Nowadays, additive manufacturing method has been used extensively to realize any product with specific attributes rather than the conventional subtractive manufacturing method. For instance, the additive manufacturing has enable us to construct a product layer-by-layer by successively depositing several materials in one session and one platform. This paper studied the properties of a 3D printed scaffold fabricated through Poly(Lactic-acid) (PLA) deposition modelling in combination with injectable hydroxyapatite (HA)/alginate as cell carrier. The scaffold was designed to serve as a spacer in cervical laminoplasty. Therefore, a series of test were conducted to elaborate the mechanical property, porosity and in-vitro toxicity testing. The results showed that the method is reliable to fabricate the scaffold as desired although the toxicity test needs more confirmation.

Wideband acoustic wave resonators composed of hetero acoustic layer structure

NASA Astrophysics Data System (ADS)

Kadota, Michio; Tanaka, Shuji

2018-07-01

“Hetero acoustic layer (HAL) surface acoustic wave (SAW) device” is a new type of SAW device using a single crystal piezoelectric thin plate supported by a substrate. In this study, a HAL SAW resonator using a LiNbO3 (LN) thin plate and a multi-layer acoustic film was designed by finite element method (FEM) and fabricated. The thickness of LN is 3.6 µm and the pitch of an interdigital transducer (IDT) (λ) is 5.24 µm for a resonance frequency of 600 MHz. The multi-layer acoustic film is composed of 3 layers of SiO2 and AlN for each, i.e., 6 layers in total, alternately deposited on a glass substrate. The HAL SAW resonator achieved a wide bandwidth of 20.3% and a high impedance ratio of 83 dB. Compared with a 0th shear horizontal (SH0) mode plate wave resonator, the performance is better and the thickness of LN is 7 times larger. The HAL SAW without a cavity is advantageous in terms of mechanical stability, thickness controllability and fabrication yield.

Microchannel plate detector and methods for their fabrication

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

Elam, Jeffrey W.; Mane, Anil U.; Peng, Qing

A multi-component tunable resistive coating and methods of depositing the coating on the surfaces of a microchannel plate (MCP) detector. The resistive coating composed of a plurality of alternating layers of a metal oxide resistive component layer and a conductive component layer composed of at least one of a metal, a metal nitride and a metal sulfide. The coating may further include an emissive layer configured to produce a secondary electron emission in response to a particle interacting with the MCP and a neutron-absorbing layer configured to respond to a neutron interacting with the MCP.

Reconfigurable and non-volatile vertical magnetic logic gates

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

Butler, J., E-mail: jbutl001@ucr.edu; Lee, B.; Shachar, M.

2014-04-28

In this paper, we discuss the concept and prototype fabrication of reconfigurable and non-volatile vertical magnetic logic gates. These gates consist of two input layers and a RESET layer. The RESET layer allows the structure to be used as either an AND or an OR gate, depending on its magnetization state. To prove this concept, the gates were fabricated using a multi-layered patterned magnetic media, in which three magnetic layers are stacked and exchange-decoupled via non-magnetic interlayers. We demonstrate the functionality of these logic gates by conducting atomic force microscopy and magnetic force microscopy (MFM) analysis of the multi-layered patternedmore » magnetic media. The logic gates operation mechanism and fabrication feasibility are both validated by the MFM imaging results.« less

Multiscale deformation behavior for multilayered steel by in-situ FE-SEM

NASA Astrophysics Data System (ADS)

Tanaka, Y.; Kishimoto, S.; Yin, F.; Kobayashi, M.; Tomimatsu, T.; Kagawa, K.

2010-03-01

The multi-scale deformation behavior of multi-layered steel during tensile loading was investigated by in-situ FE-SEM observation coupled with multi-scale pattern. The material used was multi-layered steel sheet consisting of martensitic and austenitic stainless steel layers. Prior to in-situ tensile testing, the multi-scale pattern combined with a grid and random dots were fabricated by electron beam lithography on the polished surface in the area of 1 mm2 to facilitate direct observation of multi-scale deformation. Both of the grids with pitches of 10 μm and a random speckle pattern ranging from 200 nm to a few μm sizes were drawn onto the specimen surface at same location. The electron moiré method was applied to measure the strain distribution in the deformed specimens at a millimeter scale and digital images correlation method was applied to measure the in-plane deformation and strain distribution at a micron meter scale acquired before and after at various increments of straining. The results showed that the plastic deformation in the austenitic stainless steel layer was larger than the martensitic steel layer at millimeter scale. However, heterogeneous intrinsic grain-scale plastic deformation was clearly observed and it increased with increasing the plastic deformation.

A Method to Estimate Fabric Particle Penetration Performance

DTIC Science & Technology

2014-09-08

may be needed to improve the correlation between wind tunnel component sleeve tests and bench top swatch test. The ability to predict multi-layered...within the fabric/component gap may be needed to improve the correlation between wind tunnel component sleeve tests and bench top swatch test...impermeable garment . Heat stress becomes a major problem with this approach however, as normal physiological heat loss mechanisms (especially sweat

Multi-modality nanoparticles having optically responsive shape

DOEpatents

Chen, Fanqing; Bouchard, Louis-Serge

2015-05-19

In certain embodiments novel nanoparticles (nanowontons) are provided that are suitable for multimodal imaging and/or therapy. In one embodiment, the nanoparticles include a first biocompatible (e.g., gold) layer, an inner core layer (e.g., a non-biocompatible material), and a biocompatible (e.g., gold) layer. The first gold layer includes a concave surface that forms a first outer surface of the layered nanoparticle. The second gold layer includes a convex surface that forms a second outer surface of the layered nanoparticle. The first and second gold layers encapsulate the inner core material layer. Methods of fabricating such nanoparticles are also provided.

Laser direct-write for fabrication of three-dimensional paper-based devices.

PubMed

He, P J W; Katis, I N; Eason, R W; Sones, C L

2016-08-16

We report the use of a laser-based direct-write (LDW) technique that allows the design and fabrication of three-dimensional (3D) structures within a paper substrate that enables implementation of multi-step analytical assays via a 3D protocol. The technique is based on laser-induced photo-polymerisation, and through adjustment of the laser writing parameters such as the laser power and scan speed we can control the depths of hydrophobic barriers that are formed within a substrate which, when carefully designed and integrated, produce 3D flow paths. So far, we have successfully used this depth-variable patterning protocol for stacking and sealing of multi-layer substrates, for assembly of backing layers for two-dimensional (2D) lateral flow devices and finally for fabrication of 3D devices. Since the 3D flow paths can also be formed via a single laser-writing process by controlling the patterning parameters, this is a distinct improvement over other methods that require multiple complicated and repetitive assembly procedures. This technique is therefore suitable for cheap, rapid and large-scale fabrication of 3D paper-based microfluidic devices.

Multi-spectral antireflection coating on zinc sulphide simultaneously effective in visible, eye safe laser wave length and MWIR region

NASA Astrophysics Data System (ADS)

Awasthi, Suman; Nautiyal, B. B.; Kumar, Rajiv; Bandyopadhyay, P. K.

2012-09-01

In recent years multi-spectral device is steadily growing popularity. Multi-spectral antireflection coating effective in visible region for sighting system, laser wavelength for ranging and MWIR region for thermal system can use common objective/receiver optics highly useful for state of art thermal instrumentation. In this paper, design and fabrication of antireflection coating simultaneously effective in visible region (450-650 nm), Eye safe laser wave length (1540 nm) and MWIR region (3.6-4.9 μm) has been reported. Comprehensive search method of design was used and the number of layers in the design was optimised with lowest evaluated merit function studied with respect to various layers. Finally eight-layer design stack was established using hafnium oxide as high index layer and silicon-di-oxide as low index coating material combination. The multilayer stack had been fabricated by using electron beam gun evaporation system in Symphony 9 vacuum coating unit. During layer deposition the substrate was irradiated with End-Hall ion gun. The evaporation was carried out in presence of oxygen and layer thicknesses were measured with crystal monitor. The result achieved for the antireflection coating was 85% average transmission from 450 to 650 nm in visible region, 95% transmission at 1540 nm and 96% average transmission from 3.6 to 4.9 μm in MWIR region.

Multiresonant layered plasmonic films

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

DeVetter, Brent M.; Bernacki, Bruce E.; Bennett, Wendy D.

Multi-resonant nanoplasmonic films have numerous applications in areas such as nonlinear optics, sensing, and tamper indication. While techniques such as focused ion beam milling and electron beam lithography can produce high-quality multi-resonant films, these techniques are expensive, serial processes that are difficult to scale at the manufacturing level. Here, we present the fabrication of multi-resonant nanoplasmonic films using a layered stacking technique. Periodically-spaced gold nanocup substrates were fabricated using self-assembled polystyrene nanospheres followed by oxygen plasma etching and metal deposition via magnetron sputter coating. By adjusting etch parameters and initial nanosphere size, it was possible to achieve an optical responsemore » ranging from the visible to the near-infrared. Singly resonant, flexible films were first made by performing peel-off using an adhesive-coated polyolefin film. Through stacking layers of the nanofilm, we demonstrate fabrication of multi-resonant films at a fraction of the cost and effort as compared to top-down lithographic techniques.« less

Method of fabricating a 3-dimensional tool master

DOEpatents

Bonivert, William D.; Hachman, John T.

2002-01-01

The invention is a method for the fabrication of an imprint tool master. The process begins with a metallic substrate. A layer of photoresist is placed onto the metallic substrate and a image pattern mask is then aligned to the mask. The mask pattern has opaque portions that block exposure light and "open" or transparent portions which transmit exposure light. The photoresist layer is then exposed to light transmitted through the "open" portions of the first image pattern mask and the mask is then removed. A second layer of photoresist then can be placed onto the first photoresist layer and a second image pattern mask may be placed on the second layer of photoresist. The second layer of photoresist is exposed to light, as before, and the second mask removed. The photoresist layers are developed simultaneously to produce a multi-level master mandrel upon which a conductive film is formed. A tool master can now be formed onto the conductive film. An imprint tool is then produced from the tool master. In one embodiment, nickel is electroplated onto the tool master to produce a three-dimensional imprint tool.

Realizing a facile and environmental-friendly fabrication of high-performance multi-crystalline silicon solar cells by employing ZnO nanostructures and an Al2O3 passivation layer

PubMed Central

Chen, Hong-Yan; Lu, Hong-Liang; Sun, Long; Ren, Qing-Hua; Zhang, Hao; Ji, Xin-Ming; Liu, Wen-Jun; Ding, Shi-Jin; Yang, Xiao-Feng; Zhang, David Wei

2016-01-01

Nowadays, the multi-crystalline silicon (mc-Si) solar cells dominate the photovoltaic industry. However, the current acid etching method on mc-Si surface used by firms can hardly suppress the average reflectance value below 25% in the visible light spectrum. Meanwhile, the nitric acid and the hydrofluoric contained in the etching solution is both environmental unfriendly and highly toxic to human. Here, a mc-Si solar cell based on ZnO nanostructures and an Al2O3 spacer layer is demonstrated. The eco-friendly fabrication is realized by low temperature atomic layer deposition of Al2O3 layer as well as ZnO seed layer. Moreover, the ZnO nanostructures are prepared by nontoxic and low cost hydro-thermal growth process. Results show that the best passivation quality of the n+ -type mc-Si surface can be achieved by balancing the Si dangling bond saturation level and the negative charge concentration in the Al2O3 film. Moreover, the average reflectance on cell surface can be suppressed to 8.2% in 400–900 nm range by controlling the thickness of ZnO seed layer. With these two combined refinements, a maximum solar cell efficiency of 15.8% is obtained eventually. This work offer a facile way to realize the environmental friendly fabrication of high performance mc-Si solar cells. PMID:27924911

Realizing a facile and environmental-friendly fabrication of high-performance multi-crystalline silicon solar cells by employing ZnO nanostructures and an Al2O3 passivation layer

NASA Astrophysics Data System (ADS)

Chen, Hong-Yan; Lu, Hong-Liang; Sun, Long; Ren, Qing-Hua; Zhang, Hao; Ji, Xin-Ming; Liu, Wen-Jun; Ding, Shi-Jin; Yang, Xiao-Feng; Zhang, David Wei

2016-12-01

Nowadays, the multi-crystalline silicon (mc-Si) solar cells dominate the photovoltaic industry. However, the current acid etching method on mc-Si surface used by firms can hardly suppress the average reflectance value below 25% in the visible light spectrum. Meanwhile, the nitric acid and the hydrofluoric contained in the etching solution is both environmental unfriendly and highly toxic to human. Here, a mc-Si solar cell based on ZnO nanostructures and an Al2O3 spacer layer is demonstrated. The eco-friendly fabrication is realized by low temperature atomic layer deposition of Al2O3 layer as well as ZnO seed layer. Moreover, the ZnO nanostructures are prepared by nontoxic and low cost hydro-thermal growth process. Results show that the best passivation quality of the n+ -type mc-Si surface can be achieved by balancing the Si dangling bond saturation level and the negative charge concentration in the Al2O3 film. Moreover, the average reflectance on cell surface can be suppressed to 8.2% in 400-900 nm range by controlling the thickness of ZnO seed layer. With these two combined refinements, a maximum solar cell efficiency of 15.8% is obtained eventually. This work offer a facile way to realize the environmental friendly fabrication of high performance mc-Si solar cells.

Fabrication of overlaid nanopattern arrays for plasmon memory

NASA Astrophysics Data System (ADS)

Okabe, Takao; Wadayama, Hisahiro; Taniguchi, Jun

2018-01-01

Stacking technique of nanopattern array is gathering attention to fabricate next generation data storage such as plasmon memory. This technique provides multi- overlaid nanopatterns which made by nanoimprint lithography. In the structure, several metal nanopatterned layer and resin layer as a spacer are overlaid alternately. The horizontal position of nanopatterns to under nanopatterns and thickness of resin layer as spacer should be controlled accurately, because these parameters affect reading performance and capacity of plasmon memory. In this study, we developed new alignment mark to fabricate multi- overlaid nanopatterns. The alignment accuracy with the order of 300 nm was demonstrated for Ag nanopatterns in 2 layers. The alignment mark can measure the thickness of spacer. The relationship of spacer thickness and position of scale bar on the alignment mark was measured. The usefulness of the alignment mark for highdensity plasmon memory is shown.

3D printing of tissue-simulating phantoms as a traceable standard for biomedical optical measurement

NASA Astrophysics Data System (ADS)

Dong, Erbao; Wang, Minjie; Shen, Shuwei; Han, Yilin; Wu, Qiang; Xu, Ronald

2016-01-01

Optical phantoms are commonly used to validate and calibrate biomedical optical devices in order to ensure accurate measurement of optical properties in biological tissue. However, commonly used optical phantoms are based on homogenous materials that reflect neither optical properties nor multi-layer heterogeneities of biological tissue. Using these phantoms for optical calibration may result in significant bias in biological measurement. We propose to characterize and fabricate tissue simulating phantoms that simulate not only the multi-layer heterogeneities but also optical properties of biological tissue. The tissue characterization module detects tissue structural and functional properties in vivo. The phantom printing module generates 3D tissue structures at different scales by layer-by-layer deposition of phantom materials with different optical properties. The ultimate goal is to fabricate multi-layer tissue simulating phantoms as a traceable standard for optimal calibration of biomedical optical spectral devices.

Rapid fabricating technique for multi-layered human hepatic cell sheets by forceful contraction of the fibroblast monolayer.

PubMed

Sakai, Yusuke; Koike, Makiko; Hasegawa, Hideko; Yamanouchi, Kosho; Soyama, Akihiko; Takatsuki, Mitsuhisa; Kuroki, Tamotsu; Ohashi, Kazuo; Okano, Teruo; Eguchi, Susumu

2013-01-01

Cell sheet engineering is attracting attention from investigators in various fields, from basic research scientists to clinicians focused on regenerative medicine. However, hepatocytes have a limited proliferation potential in vitro, and it generally takes a several days to form a sheet morphology and multi-layered sheets. We herein report our rapid and efficient technique for generating multi-layered human hepatic cell (HepaRG® cell) sheets using pre-cultured fibroblast monolayers derived from human skin (TIG-118 cells) as a feeder layer on a temperature-responsive culture dish. Multi-layered TIG-118/HepaRG cell sheets with a thick morphology were harvested on day 4 of culturing HepaRG cells by forceful contraction of the TIG-118 cells, and the resulting sheet could be easily handled. In addition, the human albumin and alpha 1-antitrypsin synthesis activities of TIG-118/HepaRG cells were approximately 1.2 and 1.3 times higher than those of HepaRG cells, respectively. Therefore, this technique is considered to be a promising modality for rapidly fabricating multi-layered human hepatocyte sheets from cells with limited proliferation potential, and the engineered cell sheet could be used for cell transplantation with highly specific functions.

High conductivity and transparent aluminum-based multi-layer source/drain electrodes for thin film transistors

NASA Astrophysics Data System (ADS)

Yao, Rihui; Zhang, Hongke; Fang, Zhiqiang; Ning, Honglong; Zheng, Zeke; Li, Xiaoqing; Zhang, Xiaochen; Cai, Wei; Lu, Xubing; Peng, Junbiao

2018-02-01

In this study, high conductivity and transparent multi-layer (AZO/Al/AZO-/Al/AZO) source/drain (S/D) electrodes for thin film transistors were fabricated via conventional physical vapor deposition approaches, without toxic elements or further thermal annealing process. The 68 nm-thick multi-layer films with excellent optical properties (transparency: 82.64%), good electrical properties (resistivity: 6.64  ×  10-5 Ω m, work function: 3.95 eV), and superior surface roughness (R q   =  0.757 nm with scanning area of 5  ×  5 µm2) were fabricated as the S/D electrodes. Significantly, comprehensive performances of AZO films are enhanced by the insertion of ultra-thin Al layers. The optimal transparent TFT with this multi-layer S/D electrodes exhibited a decent electrical performance with a saturation mobility (µ sat) of 3.2 cm2 V-1 s-1, an I on/I off ratio of 1.59  ×  106, a subthreshold swing of 1.05 V/decade. The contact resistance of AZO/Al/AZO/Al/AZO multi-layer electrodes is as low as 0.29 MΩ. Moreover, the average visible light transmittance of the unpatterned multi-layers constituting a whole transparent TFT could reach 72.5%. The high conductivity and transparent multi-layer S/D electrodes for transparent TFTs possessed great potential for the applications of the green and transparent displays industry.

Multi-layer micro/nanofluid devices with bio-nanovalves

DOEpatents

Li, Hao; Ocola, Leonidas E.; Auciello, Orlando H.; Firestone, Millicent A.

2013-01-01

A user-friendly multi-layer micro/nanofluidic flow device and micro/nano fabrication process are provided for numerous uses. The multi-layer micro/nanofluidic flow device can comprise: a substrate, such as indium tin oxide coated glass (ITO glass); a conductive layer of ferroelectric material, preferably comprising a PZT layer of lead zirconate titanate (PZT) positioned on the substrate; electrodes connected to the conductive layer; a nanofluidics layer positioned on the conductive layer and defining nanochannels; a microfluidics layer positioned upon the nanofluidics layer and defining microchannels; and biomolecular nanovalves providing bio-nanovalves which are moveable from a closed position to an open position to control fluid flow at a nanoscale.

Fabrication of multiwall carbon nanotube sheet based hydrogen sensor on a stacking multi-layer structure.

PubMed

Yan, Keyi; Toku, Yuhki; Morita, Yasuyuki; Ju, Yang

2018-06-22

In this research, we propose a new simple method to fabricate hydrogen gas sensor by stacking the multiwall carbon nanotube (MWCNT) sheets. MWCNT sheet offers a larger surface area and more CNT contacts, which are key factors for gas sensing, because of its super-high alignment and end-to-end structure comparing to the traditional CNT film. Besides, MWCNT sheet can be directly drawn from the spinnable CNT array in large scales. Therefore, this method is a potential answer for the mass production and commercialization of CNT based sensor with high response. By stacking different layers of sheet, microstructure and CNT interactions in the layers were changed and their influences towards gas sensing were investigated. It was observed that the sample with 3 layers of sheet and functionalized with 3 nm-thick Pd showed the best gas sensing performance with a response of 12.31% at 4% H2 and response time below 200 s. © 2018 IOP Publishing Ltd.

Fabrication of magnetic bubble memory overlay

NASA Technical Reports Server (NTRS)

1973-01-01

Self-contained magnetic bubble memory overlay is fabricated by process that employs epitaxial deposition to form multi-layered complex of magnetically active components on single chip. Overlay fabrication comprises three metal deposition steps followed by subtractive etch.

Use of Vacuum Bagging for Fabricating Thermoplastic Microfluidic Devices

PubMed Central

Cassano, Christopher L.; Simon, Andrew J.; Liu, Wei; Fredrickson, Carl; Fan, Z. Hugh

2014-01-01

In this work we present a novel thermal bonding method for thermoplastic microfluidic devices. This simple method employs a modified vacuum bagging technique, a concept borrowed from the aerospace industry, to produce conventional thick substrate microfluidic devices, as well as multi-layer film devices. The bonds produced using this method are superior to those obtained using conventional thermal bonding methods, including thermal lamination, and are capable of sustaining burst pressures in excess of 550 kPa. To illustrate the utility of this method, thick substrate devices were produced, as well as a six-layer film device that incorporated several complex features. PMID:25329244

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.

Gas-driven microturbine

DOEpatents

Sniegowski, Jeffrey J.; Rodgers, Murray S.; McWhorter, Paul J.; Aeschliman, Daniel P.; Miller, William M.

2002-01-01

A microturbine fabricated by a three-level semiconductor batch-fabrication process based on polysilicon surface-micromachining. The microturbine comprises microelectromechanical elements formed from three polysilicon multi-layer surfaces applied to a silicon substrate. Interleaving sacrificial oxide layers provides electrical and physical isolation, and selective etching of both the sacrificial layers and the polysilicon layers allows formation of individual mechanical and electrical elements as well as the required space for necessary movement of rotating turbine parts and linear elements.

Rapid Fabricating Technique for Multi-Layered Human Hepatic Cell Sheets by Forceful Contraction of the Fibroblast Monolayer

PubMed Central

Sakai, Yusuke; Koike, Makiko; Hasegawa, Hideko; Yamanouchi, Kosho; Soyama, Akihiko; Takatsuki, Mitsuhisa; Kuroki, Tamotsu; Ohashi, Kazuo; Okano, Teruo; Eguchi, Susumu

2013-01-01

Cell sheet engineering is attracting attention from investigators in various fields, from basic research scientists to clinicians focused on regenerative medicine. However, hepatocytes have a limited proliferation potential in vitro, and it generally takes a several days to form a sheet morphology and multi-layered sheets. We herein report our rapid and efficient technique for generating multi-layered human hepatic cell (HepaRG® cell) sheets using pre-cultured fibroblast monolayers derived from human skin (TIG-118 cells) as a feeder layer on a temperature-responsive culture dish. Multi-layered TIG-118/HepaRG cell sheets with a thick morphology were harvested on day 4 of culturing HepaRG cells by forceful contraction of the TIG-118 cells, and the resulting sheet could be easily handled. In addition, the human albumin and alpha 1-antitrypsin synthesis activities of TIG-118/HepaRG cells were approximately 1.2 and 1.3 times higher than those of HepaRG cells, respectively. Therefore, this technique is considered to be a promising modality for rapidly fabricating multi-layered human hepatocyte sheets from cells with limited proliferation potential, and the engineered cell sheet could be used for cell transplantation with highly specific functions. PMID:23923035

Formation of multiple levels of porous silicon for buried insulators and conductors in silicon device technologies

DOEpatents

Blewer, Robert S.; Gullinger, Terry R.; Kelly, Michael J.; Tsao, Sylvia S.

1991-01-01

A method of forming a multiple level porous silicon substrate for semiconductor integrated circuits including anodizing non-porous silicon layers of a multi-layer silicon substrate to form multiple levels of porous silicon. At least one porous silicon layer is then oxidized to form an insulating layer and at least one other layer of porous silicon beneath the insulating layer is metallized to form a buried conductive layer. Preferably the insulating layer and conductive layer are separated by an anodization barrier formed of non-porous silicon. By etching through the anodization barrier and subsequently forming a metallized conductive layer, a fully or partially insulated buried conductor may be fabricated under single crystal silicon.

Weaving multi-layer fabrics for reinforcement of engineering components

NASA Technical Reports Server (NTRS)

Hill, B. J.; Mcilhagger, R.; Mclaughlin, P.

1993-01-01

The performance of interlinked, multi-layer fabrics and near net shape preforms for engineering applications, woven on a 48 shaft dobby loom using glass, aramid, and carbon continuous filament yarns is assessed. The interlinking was formed using the warp yarns. Two basic types of structure were used. The first used a single warp beam and hence each of the warp yarns followed a similar path to form four layer interlinked reinforcements and preforms. In the second two warp beams were used, one for the interlinking yarns which pass from the top to the bottom layer through-the-thickness of the fabric and vice versa, and the other to provide 'straight' yarns in the body of the structure to carry the axial loading. Fabrics up to 15mm in thickness were constructed with varying amounts of through-the-thickness reinforcement. Tapered T and I sections were also woven, with the shaping produced by progressive removal of ends during construction. These fabrics and preforms were impregnated with resin and cured to form composite samples for testing. Using these two basic types of construction, the influence of reinforcement construction and the proportion and type of interlinking yarn on the performance of the composite was assessed.

A method for building low loss multi-layer wiring for superconducting microwave devices

NASA Astrophysics Data System (ADS)

Dunsworth, A.; Barends, R.; Chen, Yu; Chen, Zijun; Chiaro, B.; Fowler, A.; Foxen, B.; Jeffrey, E.; Kelly, J.; Klimov, P. V.; Lucero, E.; Mutus, J. Y.; Neeley, M.; Neill, C.; Quintana, C.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T. C.; Neven, H.; Martinis, John M.; Megrant, A.

2018-02-01

Complex integrated circuits require multiple wiring layers. In complementary metal-oxide-semiconductor processing, these layers are robustly separated by amorphous dielectrics. These dielectrics would dominate energy loss in superconducting integrated circuits. Here, we describe a procedure that capitalizes on the structural benefits of inter-layer dielectrics during fabrication and mitigates the added loss. We use a deposited inter-layer dielectric throughout fabrication and then etch it away post-fabrication. This technique is compatible with foundry level processing and can be generalized to make many different forms of low-loss wiring. We use this technique to create freestanding aluminum vacuum gap crossovers (airbridges). We characterize the added capacitive loss of these airbridges by connecting ground planes over microwave frequency λ/4 coplanar waveguide resonators and measuring resonator loss. We measure a low power resonator loss of ˜3.9 × 10-8 per bridge, which is 100 times lower than that of dielectric supported bridges. We further characterize these airbridges as crossovers, control line jumpers, and as part of a coupling network in gmon and fluxmon qubits. We measure qubit characteristic lifetimes (T1s) in excess of 30 μs in gmon devices.

Organic solar cells with graded absorber layers processed from nanoparticle dispersions.

PubMed

Gärtner, Stefan; Reich, Stefan; Bruns, Michael; Czolk, Jens; Colsmann, Alexander

2016-03-28

The fabrication of organic solar cells with advanced multi-layer architectures from solution is often limited by the choice of solvents since most organic semiconductors dissolve in the same aromatic agents. In this work, we investigate multi-pass deposition of organic semiconductors from eco-friendly ethanol dispersion. Once applied, the nanoparticles are insoluble in the deposition agent, allowing for the application of further nanoparticulate layers and hence for building poly(3-hexylthiophene-2,5-diyl):indene-C60 bisadduct absorber layers with vertically graded polymer and conversely graded fullerene concentration. Upon thermal annealing, we observe some degrees of polymer/fullerene interdiffusion by means of X-ray photoelectron spectroscopy and Kelvin probe force microscopy. Replacing the common bulk-heterojunction by such a graded photo-active layer yields an enhanced fill factor of the solar cell due to an improved charge carrier extraction, and consequently an overall power conversion efficiency beyond 4%. Wet processing of such advanced device architectures paves the way for a versatile, eco-friendly and industrially feasible future fabrication of organic solar cells with advanced multi-layer architectures.

Multi-layer structures with thermal and acoustic properties for building rehabilitation

NASA Astrophysics Data System (ADS)

Bessa, J.; Mota, C.; Cunha, F.; Merino, F.; Fangueiro, R.

2017-10-01

This work compares the use of different sustainable materials in the design of multilayer structures for the rehabilitation of buildings in terms of thermal and acoustic properties. These structures were obtained by compression moulding and thermal and acoustic tests were further carried out for the quantification of the respective insulation properties of composite materials obtained. The experimental results show that the use of polyurethane (PUR) foams and jute fabric reinforcing biocomposites promotes interesting properties of thermal and acoustic insulation. A multi-layer structure composed by PUR foam on the intermediate layer revealed thermal resistances until 0.272 m2 K W-1. On the other hand, the use of jute fabric reinforcing biocomposites on exterior layer promoted a noise reduction at 500 Hz until 8.3 dB. These results allow to conclude that the use of PUR foams and jute fabric reinforcing biocomposites can be used successfully in rehabilitation of buildings, when the thermal and acoustic insulation is looked for.

Fabrication and Optimization of Bilayered Nanoporous Anodic Alumina Structures as Multi-Point Interferometric Sensing Platform

PubMed Central

Nemati, Mahdieh; Santos, Abel

2018-01-01

Herein, we present an innovative strategy for optimizing hierarchical structures of nanoporous anodic alumina (NAA) to advance their optical sensing performance toward multi-analyte biosensing. This approach is based on the fabrication of multilayered NAA and the formation of differential effective medium of their structure by controlling three fabrication parameters (i.e., anodization steps, anodization time, and pore widening time). The rationale of the proposed concept is that interferometric bilayered NAA (BL-NAA), which features two layers of different pore diameters, can provide distinct reflectometric interference spectroscopy (RIfS) signatures for each layer within the NAA structure and can therefore potentially be used for multi-point biosensing. This paper presents the structural fabrication of layered NAA structures, and the optimization and evaluation of their RIfS optical sensing performance through changes in the effective optical thickness (EOT) using quercetin as a model molecule. The bilayered or funnel-like NAA structures were designed with the aim of characterizing the sensitivity of both layers of quercetin molecules using RIfS and exploring the potential of these photonic structures, featuring different pore diameters, for simultaneous size-exclusion and multi-analyte optical biosensing. The sensing performance of the prepared NAA platforms was examined by real-time screening of binding reactions between human serum albumin (HSA)-modified NAA (i.e., sensing element) and quercetin (i.e., analyte). BL-NAAs display a complex optical interference spectrum, which can be resolved by fast Fourier transform (FFT) to monitor the EOT changes, where three distinctive peaks were revealed corresponding to the top, bottom, and total layer within the BL-NAA structures. The spectral shifts of these three characteristic peaks were used as sensing signals to monitor the binding events in each NAA pore in real-time upon exposure to different concentrations of quercetin. The multi-point sensing performance of BL-NAAs was determined for each pore layer, with an average sensitivity and low limit of detection of 600 nm (mg mL−1)−1 and 0.14 mg mL−1, respectively. BL-NAAs photonic structures have the capability to be used as platforms for multi-point RIfS sensing of biomolecules that can be further extended for simultaneous size-exclusion separation and multi-analyte sensing using these bilayered nanostructures. PMID:29415436

Methods and systems for integrating fluid dispensing technology with stereolithography

DOEpatents

Medina, Francisco; Wicker, Ryan; Palmer, Jeremy A.; Davis, Don W.; Chavez, Bart D.; Gallegos, Phillip L.

2010-02-09

An integrated system and method of integrating fluid dispensing technologies (e.g., direct-write (DW)) with rapid prototyping (RP) technologies (e.g., stereolithography (SL)) without part registration comprising: an SL apparatus and a fluid dispensing apparatus further comprising a translation mechanism adapted to translate the fluid dispensing apparatus along the Z-, Y- and Z-axes. The fluid dispensing apparatus comprises: a pressurized fluid container; a valve mechanism adapted to control the flow of fluid from the pressurized fluid container; and a dispensing nozzle adapted to deposit the fluid in a desired location. To aid in calibration, the integrated system includes a laser sensor and a mechanical switch. The method further comprises building a second part layer on top of the fluid deposits and optionally accommodating multi-layered circuitry by incorporating a connector trace. Thus, the present invention is capable of efficiently building single and multi-material SL fabricated parts embedded with complex three-dimensional circuitry using DW.

Fabrication of In Vitro Cancer Microtissue Array on Fibroblast-Layered Nanofibrous Membrane by Inkjet Printing

PubMed Central

Park, Tae-Min; Kang, Donggu; Jang, Ilho; Yun, Won-Soo; Shim, Jin-Hyung; Jeong, Young Hun; Kwak, Jong-Young; Yoon, Sik; Jin, Songwan

2017-01-01

In general, a drug candidate is evaluated using 2D-cultured cancer cells followed by an animal model. Despite successful preclinical testing, however, most drugs that enter human clinical trials fail. The high failure rates are mainly caused by incompatibility between the responses of the current models and humans. Here, we fabricated a cancer microtissue array in a multi-well format that exhibits heterogeneous and batch-to-batch structure by continuous deposition of collagen-suspended Hela cells on a fibroblast-layered nanofibrous membrane via inkjet printing. Expression of both Matrix Metalloproteinase 2 (MMP2) and Matrix Metalloproteinase 9 (MMP9) was higher in cancer microtissues than in fibroblast-free microtissues. The fabricated microtissues were treated with an anticancer drug, and high drug resistance to doxorubicin occurred in cancer microtissues but not in fibroblast-free microtissues. These results introduce an inkjet printing fabrication method for cancer microtissue arrays, which can be used for various applications such as early drug screening and gradual 3D cancer studies. PMID:29112150

The layer boundary effect on multi-layer mesoporous TiO 2 film based dye sensitized solar cells

DOE PAGES

Xu, Feng; Zhu, Kai; Zhao, Yixin

2016-10-10

Multi-layer mesoporous TiO 2 prepared by screen printing is widely used for fabrication of high-efficiency dye-sensitized solar cells (DSSCs). Here, we compare the three types of ~10 um thick mesoporous TiO 2 films, which were screen printed as 1-, 2- and 4-layers using the same TiO 2 nanocrystal paste. The layer boundary of the multi-layer mesoporous TiO 2 films was observed in the cross-section SEM. The existence of a layer boundary could reduce the photoelectron diffusion length with the increase of layer number. However, the photoelectron diffusion lengths of the Z907 dye sensitized solar cells based on these different layeredmore » mesoporous TiO 2 films are all longer than the film thickness. Consequently, the photovoltaic performance seems to have little dependence on the layer number of the multi-layer TiO 2 based DSSCs.« less

The layer boundary effect on multi-layer mesoporous TiO 2 film based dye sensitized solar cells

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

Xu, Feng; Zhu, Kai; Zhao, Yixin

Multi-layer mesoporous TiO 2 prepared by screen printing is widely used for fabrication of high-efficiency dye-sensitized solar cells (DSSCs). Here, we compare the three types of ~10 um thick mesoporous TiO 2 films, which were screen printed as 1-, 2- and 4-layers using the same TiO 2 nanocrystal paste. The layer boundary of the multi-layer mesoporous TiO 2 films was observed in the cross-section SEM. The existence of a layer boundary could reduce the photoelectron diffusion length with the increase of layer number. However, the photoelectron diffusion lengths of the Z907 dye sensitized solar cells based on these different layeredmore » mesoporous TiO 2 films are all longer than the film thickness. Consequently, the photovoltaic performance seems to have little dependence on the layer number of the multi-layer TiO 2 based DSSCs.« less

Lattice-mismatched GaInP LED devices and methods of fabricating same

DOEpatents

Mascarenhas, Angelo; Steiner, Myles A; Bhusal, Lekhnath; Zhang, Yong

2014-10-21

A method (100) of fabricating an LED or the active regions of an LED and an LED (200). The method includes growing, depositing or otherwise providing a bottom cladding layer (208) of a selected semiconductor alloy with an adjusted bandgap provided by intentionally disordering the structure of the cladding layer (208). A first active layer (202) may be grown above the bottom cladding layer (208) wherein the first active layer (202) is fabricated of the same semiconductor alloy, with however, a partially ordered structure. The first active layer (202) will also be fabricated to include a selected n or p type doping. The method further includes growing a second active layer (204) above the first active layer (202) where the second active layer (204) Is fabricated from the same semiconductor alloy.

Fabrication of 3D polymer photonic crystals for near-IR applications

NASA Astrophysics Data System (ADS)

Yao, Peng; Qiu, Liang; Shi, Shouyuan; Schneider, Garrett J.; Prather, Dennis W.; Sharkawy, Ahmed; Kelmelis, Eric

2008-02-01

Photonic crystals[1, 2] have stirred enormous research interest and became a growing enterprise in the last 15 years. Generally, PhCs consist of periodic structures that possess periodicity comparable with the wavelength that the PhCs are designed to modulate. If material and periodic pattern are properly selected, PhCs can be applied to many applications based on their unique properties, including photonic band gaps (PBG)[3], self-collimation[4], super prism[5], etc. Strictly speaking, PhCs need to possess periodicity in three dimensions to maximize their advantageous capabilities. However, many current research is based on scaled two-dimensional PhCs, mainly due to the difficulty of fabrication such three-dimensional PhCs. Many approaches have been explored for the fabrication of 3D photonic crystals, including layer-by-layer surface micromachining[6], glancing angle deposition[7], 3D micro-sculpture method[8], self-assembly[9] and lithographical methods[10-12]. Among them, lithographic methods became increasingly accepted due to low costs and precise control over the photonic crystal structure. There are three mostly developed lithographical methods, namely X-ray lithography[10], holographic lithography[11] and two-photon polymerization[12]. Although significant progress has been made in developing these lithography-based technologies, these approaches still suffer from significant disadvantages. X-ray lithography relies on an expensive radiation source. Holographic lithography lacks the flexibility to create engineered defects, and multi-photon polymerization is not suitable for parallel fabrication. In our previous work, we developed a multi-layer photolithography processes[13, 14] that is based on multiple resist application and enhanced absorption upon exposure. Using a negative lift-off resist (LOR) and 254nm DUV source, we have demonstrated fabrication of 3D arbitrary structures with feature size of several microns. However, severe intermixing problem occurred as we reduced the lattice constant for near-IR applications. In this work, we address this problem by employing SU8. The exposure is vertically confined by using a mismatched 220nm DUV source. Intermixing problem is eliminated due to more densely crosslinked resist molecules. Using this method, we have demonstrated 3D "woodpile" structure with 1.55μm lattice constant and a 2mm-by-2mm pattern area.

Design and simulation of multi-color infrared CMOS metamaterial absorbers

NASA Astrophysics Data System (ADS)

Cheng, Zhengxi; Chen, Yongping; Ma, Bin

2016-05-01

Metamaterial electromagnetic wave absorbers, which usually can be fabricated in a low weight thin film structure, have a near unity absorptivity in a special waveband, and therefore have been widely applied from microwave to optical waveband. To increase absorptance of CMOS MEMS devices in 2-5 μmm waveband, multi-color infrared metamaterial absorbers are designed with CSMC 0.5 μmm 2P3M and 0.18 μmm 1P6M CMOS technology in this work. Metal-insulator-metal (MIM) three-layer MMAs and Insulator-metal-insulator-metal (MIMI) four-layer MMAs are formed by CMOS metal interconnect layers and inter metal dielectrics layer. To broaden absorption waveband in 2-5μmm range, MMAs with a combination of different sizes cross bars are designed. The top metal layer is a periodic aluminum square array or cross bar array with width ranging from submicron to several microns. The absorption peak position and intensity of MMAs can be tuned by adjusting the top aluminum micro structure array. Post-CMOS process is adopted to fabricate MMAs. The infrared absorption spectra of MMAs are verified with finite element method simulation, and the effects of top metal structure sizes, patterns, and films thickness are also simulated and intensively discussed. The simulation results show that CMOS MEMS MMAs enhance infrared absorption in 2-20 μmm. The MIM broad MMA has an average absorptance of 0.22 in 2-5 μmm waveband, and 0.76 in 8-14 μm waveband. The CMOS metamaterial absorbers can be inherently integrated in many kinds of MEMS devices fabricated with CMOS technology, such as uncooled bolometers, infrared thermal emitters.

Self-Assembled Nanoporous Biofilms from Functionalized Nanofibrous M13 Bacteriophage.

PubMed

Devaraj, Vasanthan; Han, Jiye; Kim, Chuntae; Kang, Yong-Cheol; Oh, Jin-Woo

2018-06-12

Highly periodic and uniform nanostructures, based on a genetically engineered M13 bacteriophage, displayed unique properties at the nanoscale that have the potential for a variety of applications. In this work, we report a multilayer biofilm with self-assembled nanoporous surfaces involving a nanofiber-like genetically engineered 4E-type M13 bacteriophage, which was fabricated using a simple pulling method. The nanoporous surfaces were effectively formed by using the networking-like structural layers of the M13 bacteriophage during self-assembly. Therefore, an external template was not required. The actual M13 bacteriophage-based fabricated multilayered biofilm with porous nanostructures agreed well with experimental and simulation results. Pores formed in the final layer had a diameter of about 150⁻500 nm and a depth of about 15⁻30 nm. We outline a filter application for this multilayered biofilm that enables selected ions to be extracted from a sodium chloride solution. Here, we describe a simple, environmentally friendly, and inexpensive fabrication approach with large-scale production potential. The technique and the multi-layered biofilms produced may be applied to sensor, filter, plasmonics, and bio-mimetic fields.

Ridge InGaAs/InP multi-quantum-well selective growth in nanoscale trenches on Si (001) substrate

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

Li, S.; Zhou, X.; Li, M.

Metal organic chemical vapor deposition of InGaAs/InP multi-quantum-well in nanoscale V-grooved trenches on Si (001) substrate was studied using the aspect ratio trapping method. A high quality GaAs/InP buffer layer with two convex (111) B facets was selectively grown to promote the highly uniform, single-crystal ridge InP/InGaAs multi-quantum-well structure growth. Material quality was confirmed by transmission electron microscopy and room temperature micro-photoluminescence measurements. This approach shows great promise for the fabrication of photonics devices and nanolasers on Si substrate.

Highly-transparent multi-layered spin-coated silk fibroin film

NASA Astrophysics Data System (ADS)

Wasapinyokul, Kamol; Kaewpirom, Supranee; Chuwongin, Santhad; Boonsang, Siridech

2017-10-01

In this study, the silk fibroin films with different numbers of layers were fabricated by the spin-coating method and their optical transmittances were observed. The process to synthesise the silk fibroin solution was explained - starting from the silk cocoon until the silk-fibroin solution, approximately 7.5% concentration wt/vol, was obtained. The solution was spin-coated onto clean glass substrates to fabricate samples. Totally 10 samples with different numbers of layers, from 1 to 5 layers, were obtained. All samples can be separated into two groups: those left dried at room temperature after spin-coating and those heated at 60°C. They were then measured for their transmittance over the visible-to-near-infrared region. All samples exhibited the high transmittance where the values were at 95% and 98%, for the samples at room temperature and those at 60°C, respectively. This was believed to be due to the heating effect that caused the silk fibroin to arrange itself after being heated, hence the higher transmittance. These high transmittances were maintained regardless of the number of layers and length of heating time. Results from this study could be used to fabricate a silk fibroin film with high optical transmittance and adjustable other properties.

A trifunctional multi-walled carbon nanotubes/polyethylene glycol (MWCNT/PEG)-coated separator through a layer-by-layer coating strategy for high-energy Li–S batteries

DOE PAGES

Luo, Liu; Chung, Sheng-Heng; Manthiram, Arumugam

2016-10-11

In this study, a trifunctional separator fabricated by using a light-weight layer-by-layer multi-walled carbon nanotubes/polyethylene glycol (MWCNT/PEG) coating has been explored in lithium–sulfur (Li–S) batteries. The conductive MWCNT/PEG coating serves as (i) an upper current collector for accelerating the electron transport and benefiting the electrochemical reaction kinetics of the cell, (ii) a net-like filter for blocking and intercepting the migrating polysulfides through a synergistic effect including physical and chemical interactions, and (iii) a layered barrier for inhibiting the continuous diffusion and alleviating the volume change of the trapped active material by introducing a “buffer zone” in between the coated layers.more » The multi-layered MWCNT/PEG coating allows the use of the conventional pure sulfur cathode with a high sulfur content (78 wt%) and high sulfur loading (up to 6.5 mg cm -2) to achieve a high initial discharge capacity of 1206 mA h g -1 at C/5 rate, retaining a superior capacity of 630 mA h g -1 after 300 cycles. Lastly, the MWCNT/PEG-coated separator optimized by the facile layer-by-layer coating method provides a promising and feasible option for advanced Li–S batteries with high energy density.« less

Fabricating optical phantoms to simulate skin tissue properties and microvasculatures

NASA Astrophysics Data System (ADS)

Sheng, Shuwei; Wu, Qiang; Han, Yilin; Dong, Erbao; Xu, Ronald

2015-03-01

This paper introduces novel methods to fabricate optical phantoms that simulate the morphologic, optical, and microvascular characteristics of skin tissue. The multi-layer skin-simulating phantom was fabricated by a light-cured 3D printer that mixed and printed the colorless light-curable ink with the absorption and the scattering ingredients for the designated optical properties. The simulated microvascular network was fabricated by a soft lithography process to embed microchannels in polydimethylsiloxane (PDMS) phantoms. The phantoms also simulated vascular anomalies and hypoxia commonly observed in cancer. A dual-modal multispectral and laser speckle imaging system was used for oxygen and perfusion imaging of the tissue-simulating phantoms. The light-cured 3D printing technique and the soft lithography process may enable freeform fabrication of skin-simulating phantoms that embed microvessels for image and drug delivery applications.

Fabrication of sensitive enzymatic biosensor based on multi-layered reduced graphene oxide added PtAu nanoparticles-modified hybrid electrode

PubMed Central

Hossain, Md Faruk; Park, Jae Y.

2017-01-01

A highly sensitive amperometric glucose sensor was developed by immobilization of glucose oxidase (GOx) onto multi-layer reduced graphene oxide (MRGO) sheets decorated with platinum and gold flower-like nanoparticles (PtAuNPs) modified Au substrate electrode. The fabricated MRGO/PtAuNPs modified hybrid electrode demonstrated high electrocatalytic activities toward oxidation of H2O2, to which it had a wide linear response that ranged from 0.5 to 8 mM (R2 = 0.997), and high sensitivity of 506.25 μA/mMcm2. Furthermore, glucose oxidase-chitosan composite and cationic polydiallyldimethylammonium chloride (PDDA) were assembled by a casting method on the surface of MRGO/PtAuNPs modified electrode. This as-fabricated hybrid biosensor electrode exhibited high electrocatalytic activity for the detection of glucose in PBS. It demonstrated good analytical properties in terms of a low detection limit of 1 μM (signal-to-noise ratio of 3), short response time (3 s), high sensitivity (17.85 μA/mMcm2), and a wide linear range (0.01–8 mM) for glucose sensing. These results reveal that the newly developed sensing electrode offers great promise for new type enzymatic biosensor applications. PMID:28333943

Fabrication of selective-area growth InGaN LED by mixed-source hydride vapor-phase epitaxy

NASA Astrophysics Data System (ADS)

Bae, Sung Geun; Jeon, Injun; Jeon, Hunsoo; Kim, Kyoung Hwa; Yang, Min; Yi, Sam Nyung; Lee, Jae Hak; Ahn, Hyung Soo; Yu, Young Moon; Sawaki, Nobuhiko; Kim, Suck-Whan

2018-01-01

We prepared InGaN light-emitting diodes (LEDs) with the active layers grown from a mixed source of Ga-In-N materials on an n-type GaN substrate by a selective-area growth method and three fabrication steps: photolithography, epitaxial layer growth, and metallization. The preparation followed a previously developed experimental process using apparatus for mixed-source hydride vapor-phase epitaxy (HVPE), which consisted of a multi-graphite boat, for insulating against the high temperature and to control the growth rate of epilayers, filled with the mixed source on the inside and a radio-frequency (RF) heating coil for heating to a high temperature (T > 900 °C) and for easy control of temperature outside the source zone. Two types of LEDs were prepared, with In compositions of 11.0 and 6.0% in the InGaN active layer, and room-temperature electroluminescence measurements exhibited a main peak corresponding to the In composition at either 420 or 390 nm. The consecutive growth of InGaN LEDs by the mixed-source HVPE method provides a technique for the production of LEDs with a wide range of In compositions in the active layer.

Thermal imaging for assessment of electron-beam freeform fabrication (EBF3) additive manufacturing deposits

NASA Astrophysics Data System (ADS)

Zalameda, Joseph N.; Burke, Eric R.; Hafley, Robert A.; Taminger, Karen M.; Domack, Christopher S.; Brewer, Amy; Martin, Richard E.

2013-05-01

Additive manufacturing is a rapidly growing field where 3-dimensional parts can be produced layer by layer. NASA's electron beam freeform fabrication (EBF3) technology is being evaluated to manufacture metallic parts in a space environment. The benefits of EBF3 technology are weight savings to support space missions, rapid prototyping in a zero gravity environment, and improved vehicle readiness. The EBF3 system is composed of 3 main components: electron beam gun, multi-axis position system, and metallic wire feeder. The electron beam is used to melt the wire and the multi-axis positioning system is used to build the part layer by layer. To insure a quality deposit, a near infrared (NIR) camera is used to image the melt pool and solidification areas. This paper describes the calibration and application of a NIR camera for temperature measurement. In addition, image processing techniques are presented for deposit assessment metrics.

A Weld Position Recognition Method Based on Directional and Structured Light Information Fusion in Multi-Layer/Multi-Pass Welding.

PubMed

Zeng, Jinle; Chang, Baohua; Du, Dong; Wang, Li; Chang, Shuhe; Peng, Guodong; Wang, Wenzhu

2018-01-05

Multi-layer/multi-pass welding (MLMPW) technology is widely used in the energy industry to join thick components. During automatic welding using robots or other actuators, it is very important to recognize the actual weld pass position using visual methods, which can then be used not only to perform reasonable path planning for actuators, but also to correct any deviations between the welding torch and the weld pass position in real time. However, due to the small geometrical differences between adjacent weld passes, existing weld position recognition technologies such as structured light methods are not suitable for weld position detection in MLMPW. This paper proposes a novel method for weld position detection, which fuses various kinds of information in MLMPW. First, a synchronous acquisition method is developed to obtain various kinds of visual information when directional light and structured light sources are on, respectively. Then, interferences are eliminated by fusing adjacent images. Finally, the information from directional and structured light images is fused to obtain the 3D positions of the weld passes. Experiment results show that each process can be done in 30 ms and the deviation is less than 0.6 mm. The proposed method can be used for automatic path planning and seam tracking in the robotic MLMPW process as well as electron beam freeform fabrication process.

Direct fabrication of bio-inspired gecko-like geometries with vat polymerization additive manufacturing method

NASA Astrophysics Data System (ADS)

Davoudinejad, A.; Ribo, M. M.; Pedersen, D. B.; Islam, A.; Tosello, G.

2018-08-01

Functional surfaces have proven their potential to solve many engineering problems, attracting great interest among the scientific community. Bio-inspired multi-hierarchical micro-structures grant the surfaces with new properties, such as hydrophobicity, adhesion, unique optical properties and so on. The geometry and fabrication of these surfaces are still under research. In this study, the feasibility of using direct fabrication of microscale features by additive manufacturing (AM) processes was investigated. The investigation was carried out using a specifically designed vat photopolymerization AM machine-tool suitable for precision manufacturing at the micro dimensional scale which has previously been developed, built and validated at the Technical University of Denmark. It was shown that it was possible to replicate a simplified surface inspired by the Tokay gecko, the geometry was previously designed and replicated by a complex multi-step micromanufacturing method extracted from the literature and used as benchmark. Ultimately, the smallest printed features were analyzed by conducting a sensitivity analysis to obtain the righteous parameters in terms of layer thickness and exposure time. Moreover, two more intricate designs were fabricated with the same parameters to assess the surfaces functionality by its wettability. The surface with increased density and decreased feature size showed a water contact angle (CA) of 124°  ±  0.10°, agreeing with the Cassie–Baxter model. These results indicate the possibility of using precision AM for a rapid, easy and reliable fabrication method for functional surfaces.

Method of fabricating a back-contact solar cell and device thereof

DOEpatents

Li, Bo; Smith, David; Cousins, Peter

2014-07-29

Methods of fabricating back-contact solar cells and devices thereof are described. A method of fabricating a back-contact solar cell includes forming an N-type dopant source layer and a P-type dopant source layer above a material layer disposed above a substrate. The N-type dopant source layer is spaced apart from the P-type dopant source layer. The N-type dopant source layer and the P-type dopant source layer are heated. Subsequently, a trench is formed in the material layer, between the N-type and P-type dopant source layers.

Method of fabricating a back-contact solar cell and device thereof

DOEpatents

Li, Bo; Smith, David; Cousins, Peter

2016-08-02

Methods of fabricating back-contact solar cells and devices thereof are described. A method of fabricating a back-contact solar cell includes forming an N-type dopant source layer and a P-type dopant source layer above a material layer disposed above a substrate. The N-type dopant source layer is spaced apart from the P-type dopant source layer. The N-type dopant source layer and the P-type dopant source layer are heated. Subsequently, a trench is formed in the material layer, between the N-type and P-type dopant source layers.

Numerical modelling of transient heat and moisture transport in protective clothing

NASA Astrophysics Data System (ADS)

Łapka, P.; Furmański, P.; Wisniewski, T. S.

2016-01-01

The paper presents a complex model of heat and mass transfer in a multi-layer protective clothing exposed to a flash fire and interacting with the human skin. The clothing was made of porous fabric layers separated by air gaps. The fabrics contained bound water in the fibres and moist air in the pores. The moist air was also present in the gaps between fabric layers or internal fabric layer and the skin. Three skin sublayers were considered. The model accounted for coupled heat transfer by conduction, thermal radiation and associated with diffusion of water vapour in the clothing layers and air gaps. Heat exchange due to phase transition of the bound water were also included in the model. Complex thermal and mass transfer conditions at internal or external boundaries between fabric layers and air gaps as well as air gap and skin were assumed. Special attention was paid to modelling of thermal radiation which was coming from the fire, penetrated through protective clothing and absorbed by the skin. For the first time non-grey properties as well as optical phenomena at internal or external boundaries between fabric layers and air gaps as well as air gap and skin were accounted for. A series of numerical simulations were carried out and the risk of heat injures was estimated.

Relationship between open-circuit voltage in Cu(In,Ga)Se2 solar cell and peak position of (220/204) preferred orientation near its absorber surface

NASA Astrophysics Data System (ADS)

Chantana, J.; Watanabe, T.; Teraji, S.; Kawamura, K.; Minemoto, T.

2013-11-01

Cu(In,Ga)Se2 (CIGS) absorbers with various Ga/III, Ga/(In+Ga), profiles are prepared by the so-called "multi-layer precursor method" using multi-layer co-evaporation of material sources. It is revealed that open-circuit voltage (VOC) of CIGS solar cell is primarily dependent on averaged Ga/III near the surface of its absorber. This averaged Ga/III is well predicted by peak position of (220/204) preferred orientation of CIGS film near its surface investigated by glancing-incidence X-ray diffraction with 0.1° incident angle. Finally, the peak position of (220/204) preferred orientation is proposed as a measure of VOC before solar cell fabrication.

3D printing of tissue-simulating phantoms for calibration of biomedical optical devices

NASA Astrophysics Data System (ADS)

Zhao, Zuhua; Zhou, Ximing; Shen, Shuwei; Liu, Guangli; Yuan, Li; Meng, Yuquan; Lv, Xiang; Shao, Pengfei; Dong, Erbao; Xu, Ronald X.

2016-10-01

Clinical utility of many biomedical optical devices is limited by the lack of effective and traceable calibration methods. Optical phantoms that simulate biological tissues used for optical device calibration have been explored. However, these phantoms can hardly simulate both structural and optical properties of multi-layered biological tissue. To address this limitation, we develop a 3D printing production line that integrates spin coating, light-cured 3D printing and Fused Deposition Modeling (FDM) for freeform fabrication of optical phantoms with mechanical and optical heterogeneities. With the gel wax Polydimethylsiloxane (PDMS), and colorless light-curable ink as matrix materials, titanium dioxide (TiO2) powder as the scattering ingredient, graphite powder and black carbon as the absorption ingredient, a multilayer phantom with high-precision is fabricated. The absorption and scattering coefficients of each layer are measured by a double integrating sphere system. The results demonstrate that the system has the potential to fabricate reliable tissue-simulating phantoms to calibrate optical imaging devices.

Methods for Fabricating Gradient Alloy Articles with Multi-Functional Properties

NASA Technical Reports Server (NTRS)

Hofmann, Douglas C. (Inventor); Suh, Eric J. (Inventor); Borgonia, John Paul C. (Inventor); Dillon, Robert P. (Inventor); Mulder, Jerry L. (Inventor); Gardner, Paul B. (Inventor)

2015-01-01

Systems and methods for fabricating multi-functional articles comprised of additively formed gradient materials are provided. The fabrication of multi-functional articles using the additive deposition of gradient alloys represents a paradigm shift from the traditional way that metal alloys and metal/metal alloy parts are fabricated. Since a gradient alloy that transitions from one metal to a different metal cannot be fabricated through any conventional metallurgy techniques, the technique presents many applications. Moreover, the embodiments described identify a broad range of properties and applications.

Analysis of grating doublets for achromatic beam-splitting

PubMed Central

Pacheco, Shaun; Milster, Tom; Liang, Rongguang

2015-01-01

Achromatic beam-splitting grating doublets are designed for both continuous phase and binary phase gratings. By analyzing the sensitivity to lateral shifts between the two grating layers, it is shown that continuous-profile grating doublets are extremely difficult to fabricate. Achromatic grating doublets that have profiles with a constant first spatial derivative are significantly more resistant to lateral shifts between grating layers, where one design case showed a 17 times improvement in performance. Therefore, binary phase, multi-level phase, and blazed grating doublets perform significantly better than continuous phase grating doublets in the presence of a lateral shift between two grating layers. By studying the sensitivity to fabrication errors in the height of both grating layers, one grating layer height can be adjusted to maintain excellent performance over a large wavelength range if the other grating layer is fabricated incorrectly. It is shown in one design case that the performance of an achromatic Dammann grating doublet can be improved by a factor of 215 if the heights of the grating layers are chosen to minimize the performance change in the presence of fabrication errors. PMID:26368261

High Efficiency Multijunction Solar Cells with Finely-Tuned Quantum Wells

NASA Astrophysics Data System (ADS)

Varonides, Argyrios C.

The field of high efficiency (inorganic) photovoltaics (PV) is rapidly maturing in both efficiency goals and cover all cost reduction of fabrication. On one hand, know-how from space industry in new solar cell design configurations and on the other, fabrication cost reduction challenges for terrestrial uses of solar energy, have paved the way to a new generation of PV devices, capable of capturing most of the solar spectrum. For quite a while now, the goal of inorganic solar cell design has been the total (if possible) capture-absorption of the solar spectrum from a single solar cell, designed in such a way that a multiple of incident wavelengths could be simultaneously absorbed. Multi-absorption in device physics indicates parallel existence of different materials that absorb solar photons of different energies. Bulk solid state devices absorb at specific energy thresholds, depending on their respective energy gap (EG). More than one energy gaps would on principle offer new ways of photon absorption: if such a structure could be fabricated, two or more groups of photons could be absorbed simultaneously. The point became then what lattice-matched semiconductor materials could offer such multiple levels of absorption without much recombination losses. It was soon realized that such layer multiplicity combined with quantum size effects could lead to higher efficiency collection of photo-excited carriers. At the moment, the main reason that slows down quantum effect solar cell production is high fabrication cost, since it involves primarily expensive methods of multilayer growth. Existing multi-layer cells are fabricated in the bulk, with three (mostly) layers of lattice-matched and non-lattice-matched (pseudo-morphic) semiconductor materials (GaInP/InGaN etc), where photo-carrier collection occurs in the bulk of the base (coming from the emitter which lies right under the window layer). These carriers are given excess to conduction via tunnel junction (grown between at each interface and connecting the layers in series). This basic idea of a design has proven very successful in recent years, leading to solar cells of efficiency levels well above 30% (Fraunhofer Institute's multi-gap solar cell at 40.8%, and NREL's device at 40.2% respectively). Successful alloys have demonstrated high performance, such as InxGa1 - xP alloys (x (%) of gallium phosphide and (1 - x) (%) of indium phosphide). Other successful candidates, in current use and perpetual cell design consideration, are the lattice-matched GaAs/AlGaAs and InP/GaAs pairs or AlAs/GaAs/GaAs triple layers and alloys, which are heavily used in both solar and the electronics industry.

Synthetic, multi-layer, self-oscillating vocal fold model fabrication.

PubMed

Murray, Preston R; Thomson, Scott L

2011-12-02

Sound for the human voice is produced via flow-induced vocal fold vibration. The vocal folds consist of several layers of tissue, each with differing material properties. Normal voice production relies on healthy tissue and vocal folds, and occurs as a result of complex coupling between aerodynamic, structural dynamic, and acoustic physical phenomena. Voice disorders affect up to 7.5 million annually in the United States alone and often result in significant financial, social, and other quality-of-life difficulties. Understanding the physics of voice production has the potential to significantly benefit voice care, including clinical prevention, diagnosis, and treatment of voice disorders. Existing methods for studying voice production include in vivo experimentation using human and animal subjects, in vitro experimentation using excised larynges and synthetic models, and computational modeling. Owing to hazardous and difficult instrument access, in vivo experiments are severely limited in scope. Excised larynx experiments have the benefit of anatomical and some physiological realism, but parametric studies involving geometric and material property variables are limited. Further, they are typically only able to be vibrated for relatively short periods of time (typically on the order of minutes). Overcoming some of the limitations of excised larynx experiments, synthetic vocal fold models are emerging as a complementary tool for studying voice production. Synthetic models can be fabricated with systematic changes to geometry and material properties, allowing for the study of healthy and unhealthy human phonatory aerodynamics, structural dynamics, and acoustics. For example, they have been used to study left-right vocal fold asymmetry, clinical instrument development, laryngeal aerodynamics, vocal fold contact pressure, and subglottal acoustics (a more comprehensive list can be found in Kniesburges et al.) Existing synthetic vocal fold models, however, have either been homogenous (one-layer models) or have been fabricated using two materials of differing stiffness (two-layer models). This approach does not allow for representation of the actual multi-layer structure of the human vocal folds that plays a central role in governing vocal fold flow-induced vibratory response. Consequently, one- and two-layer synthetic vocal fold models have exhibited disadvantages such as higher onset pressures than what are typical for human phonation (onset pressure is the minimum lung pressure required to initiate vibration), unnaturally large inferior-superior motion, and lack of a "mucosal wave" (a vertically-traveling wave that is characteristic of healthy human vocal fold vibration). In this paper, fabrication of a model with multiple layers of differing material properties is described. The model layers simulate the multi-layer structure of the human vocal folds, including epithelium, superficial lamina propria (SLP), intermediate and deep lamina propria (i.e., ligament; a fiber is included for anterior-posterior stiffness), and muscle (i.e., body) layers. Results are included that show that the model exhibits improved vibratory characteristics over prior one- and two-layer synthetic models, including onset pressure closer to human onset pressure, reduced inferior-superior motion, and evidence of a mucosal wave.

High color rendering index of remote-type white LEDs with multi-layered quantum dot-phosphor films and short-wavelength pass dichroic filters

NASA Astrophysics Data System (ADS)

Yoon, Hee Chang; Oh, Ji Hye; Do, Young Rag

2014-09-01

This paper introduces high color rendering index (CRI) white light-emitting diodes (W-LEDs) coated with red emitting (Sr,Ca)AlSiN3:Eu phosphors and yellowish-green emitting AgIn5S8/ZnS (AIS/ZS) quantum dots (QDs) on glass or a short-wavelength pass dichroic filter (SPDF), which transmit blue wavelength regions and reflect yellow wavelength regions. The red emitting (Sr,Ca)AlSiN3:Eu phosphor film is coated on glass and a SPDF using a screen printing method, and then the yellowish-green emitting AIS/ZS QDs are coated on the red phosphor (Sr,Ca)AlSiN3:Eu film-coated glass and SPDF using the electrospray (e-spray) method.To fabricate the red phosphor film, the optimum amount of phosphor is dispersed in a silicon binder to form a red phosphor paste. The AIS/ZS QDs are mixed with dimethylformamide (DMF), toluene, and poly(methyl methacrylate) (PMMA) for the e-spray coating. The substrates are spin-coated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to fabricate a conductive surface. The CRI of the white LEDs is improved through inserting the red phosphor film between the QD layer and the glass substrate. Furthermore, the light intensities of the multi-layered phosphor films are enhanced through changing the glass substrate to the SPDF. The correlated color temperatures (CCTs) vary as a function of the phosphor concentration in the phosphor paste. The optical properties of the yellowish-green AIS/ZS QDs and red (Sr,Ca)AlSiN3:Eu phosphors are characterized using photoluminescence (PL), and the multi-layered QD-phosphor films are measured using electroluminescence (EL) with an InGaN blue LED (λmax = 450 nm) at 60 mA.

Iron layer-dependent surface-enhanced raman scattering of hierarchical nanocap arrays

NASA Astrophysics Data System (ADS)

Chen, Lei; Sun, Huanhuan; Zhao, Yue; Gao, Renxian; Wang, Yaxin; Liu, Yang; Zhang, Yongjun; Hua, Zhong; Yang, Jinghai

2017-11-01

In this report, we fabricated the multi-layer Ag/Fe/Ag sandwich cap-shaped films on monolayer non-closed packed (ncp) polystyrene colloidal particle (PSCP) templates through a layer-by-layer (LBL) depositing method. This research focused on the surface-enhanced Raman scattering (SERS) effect of the thickness of the deposited Fe film which was controlled by the sputtering time. The SERS intensities were increased firstly, and then decreased as the thickness of Fe layer grows gradually, which is attributed to the charge transition from the Fermi level of the Ag NPs to Fe layer. The use of multi-layer Ag/Fe/Ag sandwich cap-shaped films enables us to evaluate the contribution of surface plasmon resonance and charge distribution between Ag and Fe to SERS enhancement. Our work introduced a novel system (Ag/Fe/Ag) for high performance SERS and extended the SERS application of Fe. Furthermore, we have designed the Ag/Fe/Ag SERS-active substrate as the immunoassay chip for quantitative determination of AFP-L3 which is the biomarker of hepatocellular carcinoma (HCC). The proposed research demonstrates that the SERS substrates with Ag/Fe/Ag sandwich cap-shaped arrays have a high sensitivity for bioassay.

Application of Polypyrrole Multi-Walled Carbon Nanotube Composite Layer for Detection of Mercury, Lead and Iron Ions Using Surface Plasmon Resonance Technique

PubMed Central

Sadrolhosseini, Amir Reza; Noor, A. S. M.; Bahrami, Afarin; Lim, H. N.; Talib, Zainal Abidin; Mahdi, Mohd. Adzir

2014-01-01

Polypyrrole multi-walled carbon nanotube composite layers were used to modify the gold layer to measure heavy metal ions using the surface plasmon resonance technique. The new sensor was fabricated to detect trace amounts of mercury (Hg), lead (Pb), and iron (Fe) ions. In the present research, the sensitivity of a polypyrrole multi-walled carbon nanotube composite layer and a polypyrrole layer were compared. The application of polypyrrole multi-walled carbon nanotubes enhanced the sensitivity and accuracy of the sensor for detecting ions in an aqueous solution due to the binding of mercury, lead, and iron ions to the sensing layer. The Hg ion bonded to the sensing layer more strongly than did the Pb and Fe ions. The limitation of the sensor was calculated to be about 0.1 ppm, which produced an angle shift in the region of 0.3° to 0.6°. PMID:24733263

Technology of silicon charged-particle detectors developed at the Institute of Electron Technology (ITE)

NASA Astrophysics Data System (ADS)

Wegrzecka, Iwona; Panas, Andrzej; Bar, Jan; Budzyński, Tadeusz; Grabiec, Piotr; Kozłowski, Roman; Sarnecki, Jerzy; Słysz, Wojciech; Szmigiel, Dariusz; Wegrzecki, Maciej; Zaborowski, Michał

2013-07-01

The paper discusses the technology of silicon charged-particle detectors developed at the Institute of Electron Technology (ITE). The developed technology enables the fabrication of both planar and epiplanar p+-ν-n+ detector structures with an active area of up to 50 cm2. The starting material for epiplanar structures are silicon wafers with a high-resistivity n-type epitaxial layer ( ν layer - ρ < 3 kΩcm) deposited on a highly doped n+-type substrate (ρ< 0,02Ωcm) developed and fabricated at the Institute of Electronic Materials Technology. Active layer thickness of the epiplanar detectors (νlayer) may range from 10 μm to 150 μm. Imported silicon with min. 5 kΩcm resistivity is used to fabricate planar detectors. Active layer thickness of the planar detectors (ν) layer) may range from 200 μm to 1 mm. This technology enables the fabrication of both discrete and multi-junction detectors (monolithic detector arrays), such as single-sided strip detectors (epiplanar and planar) and double-sided strip detectors (planar). Examples of process diagrams for fabrication of the epiplanar and planar detectors are presented in the paper, and selected technological processes are discussed.

Fabrication of Hadfield-Cored Multi-layer Steel Sheet by Roll-Bonding with 1.8-GPa-Strength-Grade Hot-Press-Forming Steel

NASA Astrophysics Data System (ADS)

Chin, Kwang-Geun; Kang, Chung-Yun; Park, Jaeyeong; Lee, Sunghak

2018-03-01

An austenitic Hadfield steel was roll-bonded with a 1.8-GPa-strength-grade martensitic hot-press-forming (HPF) steel to fabricate a multi-layer steel (MLS) sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2%C) to HPF (0.35%C) layers, and could be regarded as kinds of very thin multi-layers of 35 μm in thickness. The tensile test and fractographic data indicated that the MLS sheet was fractured abruptly within the elastic range by the intergranular fracture occurred in the carburized layer. This was because C was mainly segregated at prior austenite grain boundaries in the carburized layer, which weakened grain boundaries to induce the intergranular fracture. In order to solve the intergranular facture problem, the MLS sheet was tempered at 200 °C. The stress-strain curve of the tempered MLS sheet lay between those of the HPF and Hadfield sheets, and a rule of mixtures was roughly satisfied. Tensile properties of the MLS sheet were dramatically improved after the tempering, and the intergranular fracture was erased completely. In particular, the yield strength up to 1073 MPa along with the high strain hardening and excellent ductility of 32.4% were outstanding because the yield strength over 1 GPa was hardly achieved in conventional austenitic steels.

Fabrication of Hadfield-Cored Multi-layer Steel Sheet by Roll-Bonding with 1.8-GPa-Strength-Grade Hot-Press-Forming Steel

NASA Astrophysics Data System (ADS)

Chin, Kwang-Geun; Kang, Chung-Yun; Park, Jaeyeong; Lee, Sunghak

2018-05-01

An austenitic Hadfield steel was roll-bonded with a 1.8-GPa-strength-grade martensitic hot-press-forming (HPF) steel to fabricate a multi-layer steel (MLS) sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2%C) to HPF (0.35%C) layers, and could be regarded as kinds of very thin multi-layers of 35 μm in thickness. The tensile test and fractographic data indicated that the MLS sheet was fractured abruptly within the elastic range by the intergranular fracture occurred in the carburized layer. This was because C was mainly segregated at prior austenite grain boundaries in the carburized layer, which weakened grain boundaries to induce the intergranular fracture. In order to solve the intergranular facture problem, the MLS sheet was tempered at 200 °C. The stress-strain curve of the tempered MLS sheet lay between those of the HPF and Hadfield sheets, and a rule of mixtures was roughly satisfied. Tensile properties of the MLS sheet were dramatically improved after the tempering, and the intergranular fracture was erased completely. In particular, the yield strength up to 1073 MPa along with the high strain hardening and excellent ductility of 32.4% were outstanding because the yield strength over 1 GPa was hardly achieved in conventional austenitic steels.

Systems and Methods for Fabricating Objects Including Amorphous Metal Using Techniques Akin to Additive Manufacturing

NASA Technical Reports Server (NTRS)

Hofmann, Douglas (Inventor)

2017-01-01

Systems and methods in accordance with embodiments of the invention fabricate objects including amorphous metals using techniques akin to additive manufacturing. In one embodiment, a method of fabricating an object that includes an amorphous metal includes: applying a first layer of molten metallic alloy to a surface; cooling the first layer of molten metallic alloy such that it solidifies and thereby forms a first layer including amorphous metal; subsequently applying at least one layer of molten metallic alloy onto a layer including amorphous metal; cooling each subsequently applied layer of molten metallic alloy such that it solidifies and thereby forms a layer including amorphous metal prior to the application of any adjacent layer of molten metallic alloy; where the aggregate of the solidified layers including amorphous metal forms a desired shape in the object to be fabricated; and removing at least the first layer including amorphous metal from the surface.

Laser fabrication of perfect absorbers

NASA Astrophysics Data System (ADS)

Mizeikis, V.; Faniayeu, I.

2018-01-01

We describe design and characterization of electromagnetic metasurfaces consisting of sub-wavelength layers of artificially structured 3D metallic elements arranged into two-dimensional arrays. Such metasurfaces allow novel ways to control propagation, absorption, emission, and polarization state of electromagnetic waves, but their practical realization using traditional planar micro-/nano-fabrication techniques is extremely difficult at infra- red frequencies, where unit cell size must be reduced to few micrometers. We have addressed this challenge by using femtosecond direct laser write (DLW) technique as a high-resolution patterning tool for the fabrication of dielectric templates, followed by a simple metallization process. Functional metasurfaces consisting of metallic helices and vertical split-ring resonators that can be used as perfect absorbers and polarization converters at infra- red frequencies were obtained and characterized experimentally and theoretically. In the future they may find applications in narrow-band infra-red detectors and emitters, spectral filters, and combined into multi-functional, multi-layered structures.

Functionalization and Characterization of Nanomaterial Gated Field-Effect Transistor-Based Biosensors and the Design of a Multi-Analyte Implantable Biosensing Platform

NASA Astrophysics Data System (ADS)

Croce, Robert A., Jr.

Advances in semiconductor research and complementary-metal-oxide semiconductor fabrication allow for the design and implementation of miniaturized metabolic monitoring systems, as well as advanced biosensor design. The first part of this dissertation will focus on the design and fabrication of nanomaterial (single-walled carbon nanotube and quantum dot) gated field-effect transistors configured as protein sensors. These novel device structures have been functionalized with single-stranded DNA aptamers, and have shown sensor operation towards the protein Thrombin. Such advanced transistor-based sensing schemes present considerable advantages over traditional sensing methodologies in view of its miniaturization, low cost, and facile fabrication, paving the way for the ultimate realization of a multi-analyte lab-on-chip. The second part of this dissertation focuses on the design and fabrication of a needle-implantable glucose sensing platform which is based solely on photovoltaic powering and optical communication. By employing these powering and communication schemes, this design negates the need for bulky on-chip RF-based transmitters and batteries in an effort to attain extreme miniaturization required for needle-implantable/extractable applications. A complete single-sensor system coupled with a miniaturized amperometric glucose sensor has been demonstrated to exhibit reality of this technology. Furthermore, an optical selection scheme of multiple potentiostats for four different analytes (glucose, lactate, O 2 and CO2) as well as the optical transmission of sensor data has been designed for multi-analyte applications. The last part of this dissertation will focus on the development of a computational model for the amperometric glucose sensors employed in the aforementioned implantable platform. This model has been applied to single-layer single-enzyme systems, as well as multi-layer (single enzyme) systems utilizing glucose flux limiting layer-by-layer assembled outer membranes. The concentration of glucose and hydrogen peroxide within the sensor geometry, the transient response and the device response time has been simulated for both systems.

Fabric defect detection based on visual saliency using deep feature and low-rank recovery

NASA Astrophysics Data System (ADS)

Liu, Zhoufeng; Wang, Baorui; Li, Chunlei; Li, Bicao; Dong, Yan

2018-04-01

Fabric defect detection plays an important role in improving the quality of fabric product. In this paper, a novel fabric defect detection method based on visual saliency using deep feature and low-rank recovery was proposed. First, unsupervised training is carried out by the initial network parameters based on MNIST large datasets. The supervised fine-tuning of fabric image library based on Convolutional Neural Networks (CNNs) is implemented, and then more accurate deep neural network model is generated. Second, the fabric images are uniformly divided into the image block with the same size, then we extract their multi-layer deep features using the trained deep network. Thereafter, all the extracted features are concentrated into a feature matrix. Third, low-rank matrix recovery is adopted to divide the feature matrix into the low-rank matrix which indicates the background and the sparse matrix which indicates the salient defect. In the end, the iterative optimal threshold segmentation algorithm is utilized to segment the saliency maps generated by the sparse matrix to locate the fabric defect area. Experimental results demonstrate that the feature extracted by CNN is more suitable for characterizing the fabric texture than the traditional LBP, HOG and other hand-crafted features extraction method, and the proposed method can accurately detect the defect regions of various fabric defects, even for the image with complex texture.

Solar cells based on electrodeposited thin films of ZnS, CdS, CdSSe and CdTe

NASA Astrophysics Data System (ADS)

Weerasinghe, Ajith R.

The motivations of this research were to produce increased efficiency and low-cost solar cells. The production efficiency of Si solar cells has almost reached their theoretical limit, and reducing the manufacturing cost of Si solar cells is difficult to achieve due to the high-energy usage in material purifying and processing stages. Due to the low usage of materials and input energy, thin film solar cells have the potential to reduce the costs. CdS/CdTe thin film solar cells are already the cheapest on $/W basis. The cost of CdTe solar cells can be further reduced if all the semiconducting layers are fabricated using the electrodeposition (ED) method. ED method is scalable, low in the usage of energy and raw materials. These benefits lead to the cost effective production of semiconductors. The conventional method of fabricating CdS layers produces Cd containing waste solutions routinely, which adds to the cost of solar cells.ZnS, CdS and CdS(i-X)Sex buffer and window layers and CdTe absorber layers have been successfully electrodeposited and explored under this research investigation. These layers were fully characterised using complementary techniques to evaluate the material properties. Photoelectrochemical (PEC) studies, optical absorption, X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, atomic force microscopy (AFM) and Raman spectroscopy were utilised to evaluate the material properties of these solid thin film layers. ZnS and CdS thin film layers were electrodeposited from Na-free chemical precursors to avoid the group I element (Na) to reduce deterioration of CdTe devices. Deposition parameters such as, growth substrates, temperature, pH, growth cathodic voltage, stirring rate, time and chemical concentrations were identified to fabricate the above semiconductors. To further optimise these layers, a heat treatment process specific to the material was developed. In addition, the deposition parameters of CdTe layers were further optimised. This research programme has demonstrated that electrodeposited ZnS, CdS and CdTe thin film layers have material characteristics comparable with those of the materials reported in the literature and can be used in thin film solar cell devices. Furthermore, the electrolytes were used for up to two years, reducing the wastage even further, in comparison to other fabrication methods, such as chemical bath deposition. Several large-area semiconducting layers were successfully fabricated to test the scalability of the method. Nano-rods perpendicular to the glass/FTO surface with gaps among grains in CdS layers were observed. In order to reduce the possible pinholes due the gaps, a deposition of a semiconducting layer to cover completely the substrate was investigated. CdS(i-X)Sex layers were investigated to produce a layer-by-layer deposition of the material. However it was observed the surface morphology of CdS(j.X)Sex is a function of the growth parameters which produced nano-wires, nano-tubes and nano-sheets. This is the first recording of this effect for a low temperature deposition method, minimising the cost of producing this highly photosensitive material for use in various nano technology applications.The basic structure experimented was glass/conducting-glass/buffer layer/window material/absorber material/metal. By utilising all the semiconducting layers developed, several solar cell device structures were designed, fabricated and tested. This included a novel all-electrodeposited multi-layer graded bandgap device, to enhance the absorption of solar photons. The device efficiencies varied from batch to batch, and efficiencies in the range (3-7)% were observed. The variations in chemical concentrations, surface states and the presence of pin-hole defects in CdS were the main reasons for the range of efficiencies obtained. In the future work section, ways to avoid these variations and to increase efficiencies are identified and presented.

Organic-inorganic hybrid material SUNCONNECT® for photonic integrated circuit

NASA Astrophysics Data System (ADS)

Nawata, Hideyuki; Oshima, Juro; Kashino, Tsubasa

2018-02-01

In this paper, we report the feature and properties about organic-inorganic hybrid material, "SUNCONNECT®" for photonic integrated circuit. "SUNCONNECT®" materials have low propagation loss at 1310nm (0.29dB/cm) and 1550nm (0.45dB/cm) respectively. In addition, the material has high thermal resistance both high temperature annealing test at 300°C and also 260°C solder heat resistance test. For actual device application, high reliability is required. 85°C /85% test was examined by using multi-mode waveguide. As a result, it indicated that variation of insertion loss property was not changed significantly after high temperature / high humidity test. For the application to photonic integrated circuit, it was demonstrated to fabricate polymer optical waveguide by using three different methods. Single-micron core pattern can be fabricated on cladding layer by using UV lithography with proximity gap exposure. Also, single-mode waveguide can be also fabricated with over cladding. On the other hands, "Mosquito method" and imprint method can be applied to fabricate polymer optical waveguide. Remarkably, these two methods can fabricate gradedindex type optical waveguide without using photo mask. In order to evaluate the optical performance, NFP's observation, measurement of insertion loss and propagation loss by cut-back methods were carried out by using each waveguide sample.

Organic materials and devices for detecting ionizing radiation

DOEpatents

Doty, F Patrick [Livermore, CA; Chinn, Douglas A [Livermore, CA

2007-03-06

A .pi.-conjugated organic material for detecting ionizing radiation, and particularly for detecting low energy fission neutrons. The .pi.-conjugated materials comprise a class of organic materials whose members are intrinsic semiconducting materials. Included in this class are .pi.-conjugated polymers, polyaromatic hydrocarbon molecules, and quinolates. Because of their high resistivities (.gtoreq.10.sup.9 ohmcm), these .pi.-conjugated organic materials exhibit very low leakage currents. A device for detecting and measuring ionizing radiation can be made by applying an electric field to a layer of the .pi.-conjugated polymer material to measure electron/hole pair formation. A layer of the .pi.-conjugated polymer material can be made by conventional polymer fabrication methods and can be cast into sheets capable of covering large areas. These sheets of polymer radiation detector material can be deposited between flexible electrodes and rolled up to form a radiation detector occupying a small volume but having a large surface area. The semiconducting polymer material can be easily fabricated in layers about 10 .mu.m to 100 .mu.m thick. These thin polymer layers and their associated electrodes can be stacked to form unique multi-layer detector arrangements that occupy small volume.

Thermal Imaging for Assessment of Electron-Beam Free Form Fabrication (EBF(sup 3)) Additive Manufacturing Welds

NASA Technical Reports Server (NTRS)

Zalameda, Joseph N.; Burke, Eric R.; Hafley, Robert A.; Taminger, Karen M.; Domack, Christopher S.; Brewer, Amy R.; Martin, Richard E.

2013-01-01

Additive manufacturing is a rapidly growing field where 3-dimensional parts can be produced layer by layer. NASA s electron beam free-form fabrication (EBF(sup 3)) technology is being evaluated to manufacture metallic parts in a space environment. The benefits of EBF(sup 3) technology are weight savings to support space missions, rapid prototyping in a zero gravity environment, and improved vehicle readiness. The EBF(sup 3) system is composed of 3 main components: electron beam gun, multi-axis position system, and metallic wire feeder. The electron beam is used to melt the wire and the multi-axis positioning system is used to build the part layer by layer. To insure a quality weld, a near infrared (NIR) camera is used to image the melt pool and solidification areas. This paper describes the calibration and application of a NIR camera for temperature measurement. In addition, image processing techniques are presented for weld assessment metrics.

Fire resistant aircraft seat materials

NASA Technical Reports Server (NTRS)

Trabold, E. L.

1978-01-01

The establishment of a technical data base for individual seat materials in order to facilitate materials selections is reviewed. The thermal response of multi-layer constructions representative of the basic functional layers of a typical future seat is examined. These functional layers include: (1) decorative fabric cover; (2) slip sheet (topper); (3) fire blocking layer; (4) cushion reinforcement; and (5) cushioning layer. The implications for material selection for full-scale seats are discussed.

Potential of Aerostats for the Recovery of Disabled Main Battle Tanks and Other Heavy Military Vehicles and Equipment

DTIC Science & Technology

2007-08-01

designs and operates numerous passenger airships. The envelope structure consists of a laminated fabric envelope. This envelope is a large bag...Layered Aerostat Fabric This multi-layered laminate is designed to withstand the sun’s UV rays, acid rain and other environmental concerns. It is...a tough laminate , which inhibits gas loss while providing a high strength-to-weight ratio. The CL75 envelope used a laminate material woven with

Methods for batch fabrication of cold cathode vacuum switch tubes

DOEpatents

Walker, Charles A [Albuquerque, NM; Trowbridge, Frank R [Albuquerque, NM

2011-05-10

Methods are disclosed for batch fabrication of vacuum switch tubes that reduce manufacturing costs and improve tube to tube uniformity. The disclosed methods comprise creating a stacked assembly of layers containing a plurality of adjacently spaced switch tube sub-assemblies aligned and registered through common layers. The layers include trigger electrode layer, cathode layer including a metallic support/contact with graphite cathode inserts, trigger probe sub-assembly layer, ceramic (e.g. tube body) insulator layer, and metallic anode sub-assembly layer. Braze alloy layers are incorporated into the stacked assembly of layers, and can include active metal braze alloys or direct braze alloys, to eliminate costs associated with traditional metallization of the ceramic insulator layers. The entire stacked assembly is then heated to braze/join/bond the stack-up into a cohesive body, after which individual switch tubes are singulated by methods such as sawing. The inventive methods provide for simultaneously fabricating a plurality of devices as opposed to traditional methods that rely on skilled craftsman to essentially hand build individual devices.

Mechanical Drawing of Gas Sensors on Paper

PubMed Central

Mirica, Katherine A.; Weis, Jonathan G.; Schnorr, Jan M.; Esser, Birgit

2012-01-01

This communication describes a simple solvent-free method for fabricating chemoresistive gas sensors on the surface of paper. The method involves mechanical abrasion of compressed powders of sensing materials on the fibers of cellulose. We illustrate this approach by depositing conductive layers of several forms of carbon (e.g., single-walled carbon nanotubes [SWCNTs], multi-walled carbon nanotubes, and graphite) on the surface of different papers (Figure 1, Figure S1). The resulting sensors based on SWCNTs are capable of detecting NH3 gas at concentrations as low as 0.5 part-per-million. PMID:23037938

Compact Layers of Hybrid Halide Perovskites Fabricated via the Aerosol Deposition Process-Uncoupling Material Synthesis and Layer Formation.

PubMed

Panzer, Fabian; Hanft, Dominik; Gujar, Tanaji P; Kahle, Frank-Julian; Thelakkat, Mukundan; Köhler, Anna; Moos, Ralf

2016-04-08

We present the successful fabrication of CH₃NH₃PbI₃ perovskite layers by the aerosol deposition method (ADM). The layers show high structural purity and compactness, thus making them suitable for application in perovskite-based optoelectronic devices. By using the aerosol deposition method we are able to decouple material synthesis from layer processing. Our results therefore allow for enhanced and easy control over the fabrication of perovskite-based devices, further paving the way for their commercialization.

Development of a test device to characterize thermal protective performance of fabrics against hot steam and thermal radiation

NASA Astrophysics Data System (ADS)

Su, Yun; Li, Jun

2016-12-01

Steam burns severely threaten the life of firefighters in the course of their fire-ground activities. The aim of this paper was to characterize thermal protective performance of flame-retardant fabrics exposed to hot steam and low-level thermal radiation. An improved testing apparatus based on ASTM F2731-11 was developed in order to simulate the routine fire-ground conditions by controlling steam pressure, flow rate and temperature of steam box. The thermal protective performance of single-layer and multi-layer fabric system with/without an air gap was studied based on the calibrated tester. It was indicated that the new testing apparatus effectively evaluated thermal properties of fabric in hot steam and thermal radiation. Hot steam significantly exacerbated the skin burn injuries while the condensed water on the skin’s surface contributed to cool down the skin tissues during the cooling. Also, the absorbed thermal energy during the exposure and the cooling was mainly determined by the fabric’s configuration, the air gap size, the exposure time and the existence of hot steam. The research provides a effective method to characterize the thermal protection of fabric in complex conditions, which will help in optimization of thermal protection performance of clothing and reduction of steam burn.

Insertion of two-dimensional photonic crystal pattern on p-GaN layer of GaN-based light-emitting diodes using bi-layer nanoimprint lithography.

PubMed

Byeon, Kyeong-Jae; Hwang, Seon-Yong; Hong, Chang-Hee; Baek, Jong Hyeob; Lee, Heon

2008-10-01

Nanoimprint lithography (NIL) was adapted to fabricate two-dimensional (2-D) photonic crystal (PC) pattern on the p-GaN layer of InGaN/GaN multi quantum well light-emitting diodes (LEDs) structure to improve the light extraction efficiency. For the uniform transfer of the PC pattern, a bi-layer imprinting method with liquid phase resin was used. The p-GaN layer was patterned with a periodic array of holes by an inductively coupled plasma etching process, based on SiCl4/Ar plasmas. As a result, 2-D photonic crystal patterns with 144 nm, 200 nm and 347 nm diameter holes were uniformly formed on the p-GaN layer and the photoluminescence (PL) intensity of each patterned LED samples was increased by more than 2.6 times, as compared to that of the un-patterned LED sample.

Analysis of the tunable asymmetric fiber F-P cavity for fiber sensor edge-filter demodulation

NASA Astrophysics Data System (ADS)

Chen, Haitao; Liang, Youcheng

2014-12-01

An asymmetric fiber (Fabry-Pérot,F-P) interferometric cavity with good linearity and wide dynamic range is successfully designed basing on optical thin film characteristic matrix theory; by choosing the material of two different thin metallic layers, the asymmetric fiber F-P interferometric cavity is fabricated by depositing the multi-layer thin films on the optical fiber's end face. The demodulation method for the wavelength shift of fiber Bragg grating (FBG) sensor basing on the F-P cavity is demonstrated and a theoretical formula is obtained. And the experimental results coincide well with computational results obtained from the theoretical model.

Multilayer insulation blanket, fabricating apparatus and method

DOEpatents

Gonczy, John D.; Niemann, Ralph C.; Boroski, William N.

1992-01-01

An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

Method of fabricating a multilayer insulation blanket

DOEpatents

Gonczy, John D.; Niemann, Ralph C.; Boroski, William N.

1993-01-01

An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

Method of fabricating a multilayer insulation blanket

DOEpatents

Gonczy, J.D.; Niemann, R.C.; Boroski, W.N.

1993-07-06

An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

Multilayer insulation blanket, fabricating apparatus and method

DOEpatents

Gonczy, J.D.; Niemann, R.C.; Boroski, W.N.

1992-09-01

An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel. 7 figs.

Fabrication of hierarchical hybrid structures using bio-enabled layer-by-layer self-assembly.

PubMed

Hnilova, Marketa; Karaca, Banu Taktak; Park, James; Jia, Carol; Wilson, Brandon R; Sarikaya, Mehmet; Tamerler, Candan

2012-05-01

Development of versatile and flexible assembly systems for fabrication of functional hybrid nanomaterials with well-defined hierarchical and spatial organization is of a significant importance in practical nanobiotechnology applications. Here we demonstrate a bio-enabled self-assembly technique for fabrication of multi-layered protein and nanometallic assemblies utilizing a modular gold-binding (AuBP1) fusion tag. To accomplish the bottom-up assembly we first genetically fused the AuBP1 peptide sequence to the C'-terminus of maltose-binding protein (MBP) using two different linkers to produce MBP-AuBP1 hetero-functional constructs. Using various spectroscopic techniques, surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR), we verified the exceptional binding and self-assembly characteristics of AuBP1 peptide. The AuBP1 peptide tag can direct the organization of recombinant MBP protein on various gold surfaces through an efficient control of the organic-inorganic interface at the molecular level. Furthermore using a combination of soft-lithography, self-assembly techniques and advanced AuBP1 peptide tag technology, we produced spatially and hierarchically controlled protein multi-layered assemblies on gold nanoparticle arrays with high molecular packing density and pattering efficiency in simple, reproducible steps. This model system offers layer-by-layer assembly capability based on specific AuBP1 peptide tag and constitutes novel biological routes for biofabrication of various protein arrays, plasmon-active nanometallic assemblies and devices with controlled organization, packing density and architecture. Copyright © 2011 Wiley Periodicals, Inc.

Heterogeneous multi-layered IF steel with simultaneous high strength and good ductility

NASA Astrophysics Data System (ADS)

Zhang, Ling; Jiang, Xiaojuan; Wang, Yuhui; Chen, Qiang; Chen, Zhen; Zhang, Yonghong; Huang, Tianlin; Wu, Guilin

2017-07-01

Multi-layered IF steel samples were designed and fabricated by hot compression followed by cold forging of an alternating stack of cold-rolled and annealed IF steel sheets, with an aim to improve the strength of the material without losing much ductility. A very good combination of strength and ductility was achieved by proper annealing after deformation. Microstructural analysis by electron back-scatter diffraction revealed that the good combination of strength and ductility is related to a characteristic hierarchical structure that is characterized by layered and lamella structures with different length scales.

Method of fabricating an optoelectronic device having a bulk heterojunction

DOEpatents

Shtein, Max [Ann Arbor, MI; Yang, Fan [Princeton, NJ; Forrest, Stephen R [Princeton, NJ

2008-10-14

A method of fabricating an optoelectronic device comprises: depositing a first layer having protrusions over a first electrode, in which the first layer comprises a first organic small molecule material; depositing a second layer on the first layer such that the second layer is in physical contact with the first layer; in which the smallest lateral dimension of the protrusions are between 1 to 5 times the exciton diffusion length of the first organic small molecule material; and depositing a second electrode over the second layer to form the optoelectronic device. A method of fabricating an organic optoelectronic device having a bulk heterojunction is also provided and comprises: depositing a first layer with protrusions over an electrode by organic vapor phase deposition; depositing a second layer on the first layer where the interface of the first and second layers forms a bulk heterojunction; and depositing another electrode over the second layer.

One-step production of multilayered microparticles by tri-axial electro-flow focusing

NASA Astrophysics Data System (ADS)

Si, Ting; Feng, Hanxin; Li, Yang; Luo, Xisheng; Xu, Ronald

2014-03-01

Microencapsulation of drugs and imaging agents in the same carrier is of great significance for simultaneous detection and treatment of diseases. In this work, we have developed a tri-axial electro-flow focusing (TEFF) device using three needles with a novel concentric arrangement to one-step form multilayered microparticles. The TEFF process can be characterized as a multi-fluidic compound cone-jet configuration in the core of a high-speed coflowing gas stream under an axial electric field. The tri-axial liquid jet eventually breaks up into multilayered droplets. To validate the method, the effect of main process parameters on characteristics of the cone and the jet has been studied experimentally. The applied electric field can dramatically promote the stability of the compound cone and enhance the atomization of compound liquid jets. Microparticles with both three-layer, double-layer and single-layer structures have been obtained. The results show that the TEFF technique has great benefits in fabricating multilayered microparticles at smaller scales. This method will be able to one-step encapsulate multiple therapeutic and imaging agents for biomedical applications such as multi-modal imaging, drug delivery and biomedicine.

Methods of fabrication of graphene nanoribbons

DOEpatents

Zhang, Yuegang

2015-06-23

Methods of fabricating graphene nanoribbons include depositing a catalyst layer on a substrate. A masking layer is deposited on the catalyst layer. The masking layer and the catalyst layer are etched to form a structure on the substrate, the structure comprising a portion of the catalyst layer and a portion of the masking layer disposed on the catalyst layer, with sidewalls of the catalyst layer being exposed. A graphene layer is formed on a sidewall of the catalyst layer with a carbon-containing gas.

Multilayer thin-film phantoms for axial contrast transfer function measurement in optical coherence tomography.

PubMed

Agrawal, Anant; Chen, Chao-Wei; Baxi, Jigesh; Chen, Yu; Pfefer, T Joshua

2013-07-01

In optical coherence tomography (OCT), axial resolution is one of the most critical parameters impacting image quality. It is commonly measured by determining the point spread function (PSF) based on a specular surface reflection. The contrast transfer function (CTF) provides more insights into an imaging system's resolving characteristics and can be readily generated in a system-independent manner, without consideration for image pixel size. In this study, we developed a test method for determination of CTF based on multi-layer, thin-film phantoms, evaluated using spectral- and time-domain OCT platforms with different axial resolution values. Phantoms representing six spatial frequencies were fabricated and imaged. The fabrication process involved spin coating silicone films with precise thicknesses in the 8-40 μm range. Alternating layers were doped with a specified concentration of scattering particles. Validation of layer optical properties and thicknesses were achieved with spectrophotometry and stylus profilometry, respectively. OCT B-scans were used to calculate CTFs and results were compared with convetional PSF measurements based on specular reflections. Testing of these phantoms indicated that our approach can provide direct access to axial resolution characteristics highly relevant to image quality. Furthermore, tissue phantoms based on our thin-film fabrication approach may have a wide range of additional applications in optical imaging and spectroscopy.

76 FR 70117 - Notice of Intent To Grant an Exclusive License; Voltage Networking, LLC

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-10

... dielectric layer and device made therefrom''; Patent No. 6,541,288 entitled ``Method of determining... sacrificial spacer layer''; Patent No. 7,442,577 entitled ``Method of fabricating a patterned device using sacrificial spacer layer''; Patent No. 7,678,593 entitled ``Method of fabricating optical device using...

Laser microprocessing technologies for automotive, flexible electronics, and solar energy sectors

NASA Astrophysics Data System (ADS)

Nikumb, Suwas; Bathe, Ravi; Knopf, George K.

2014-10-01

Laser microprocessing technologies offer an important tool to fulfill the needs of many industrial sectors. In particular, there is growing interest in applications of these processes in the manufacturing areas such as automotive parts fabrication, printable electronics and solar energy panels. The technology is primarily driven by our understanding of the fundamental laser-material interaction, process control strategies and the advancement of significant fabrication experience over the past few years. The wide-ranging operating parameters available with respect to power, pulse width variation, beam quality, higher repetition rates as well as precise control of the energy deposition through programmable pulse shaping technologies, enables pre-defined material removal, selective scribing of individual layer within a stacked multi-layer thin film structure, texturing of material surfaces as well as precise introduction of heat into the material to monitor its characteristic properties are a few examples. In this research, results in the area of laser surface texturing of metals for added hydrodynamic lubricity to reduce friction, processing of ink-jet printed graphene oxide for flexible printed electronic circuit fabrication and scribing of multi-layer thin films for the development of photovoltaic CuInGaSe2 (CIGS) interconnects for solar panel devices will be discussed.

Stress compensation for arbitrary curvature control in vanadium dioxide phase transition actuators

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

Dong, Kaichen, E-mail: dkc12@mails.tsinghua.edu.cn, E-mail: wuj@berkeley.edu; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084

2016-07-11

Due to its thermally driven structural phase transition, vanadium dioxide (VO{sub 2}) has emerged as a promising material for micro/nano-actuators with superior volumetric work density, actuation amplitude, and repetition frequency. However, the high initial curvature of VO{sub 2} actuators severely obstructs the actuation performance and application. Here, we introduce a “seesaw” method of fabricating tri-layer cantilevers to compensate for the residual stress and realize nearly arbitrary curvature control of VO{sub 2} actuators. By simply adjusting the thicknesses of the individual layers, cantilevers with positive, zero, or negative curvatures can be engineered. The actuation amplitude can be decoupled from the curvaturemore » and controlled independently as well. Based on the experimentally measured residual stresses, we demonstrate sub-micron thick VO{sub 2} actuators with nearly zero final curvature and a high actuation amplitude simultaneously. This “seesaw” method can be further extended to the curvature engineering of other microelectromechanical system multi-layer structures where large stress-mismatch between layers are inevitable.« less

Reliability assessment of multiple quantum well avalanche photodiodes

NASA Technical Reports Server (NTRS)

Yun, Ilgu; Menkara, Hicham M.; Wang, Yang; Oguzman, Isamil H.; Kolnik, Jan; Brennan, Kevin F.; May, Gray S.; Wagner, Brent K.; Summers, Christopher J.

1995-01-01

The reliability of doped-barrier AlGaAs/GsAs multi-quantum well avalanche photodiodes fabricated by molecular beam epitaxy is investigated via accelerated life tests. Dark current and breakdown voltage were the parameters monitored. The activation energy of the degradation mechanism and median device lifetime were determined. Device failure probability as a function of time was computed using the lognormal model. Analysis using the electron beam induced current method revealed the degradation to be caused by ionic impurities or contamination in the passivation layer.

A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

NASA Astrophysics Data System (ADS)

Yoon, Sunghyun; Cho, Young-Ho

2014-11-01

We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2~1.0μW in the Human heart rate range on the skin contact area of 3.71cm2. Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves.

Fabrication of Three-dimensional Paper-based Microfluidic Devices for Immunoassays.

PubMed

Fernandes, Syrena C; Wilson, Daniel J; Mace, Charles R

2017-03-09

Paper wicks fluids autonomously due to capillary action. By patterning paper with hydrophobic barriers, the transport of fluids can be controlled and directed within a layer of paper. Moreover, stacking multiple layers of patterned paper creates sophisticated three-dimensional microfluidic networks that can support the development of analytical and bioanalytical assays. Paper-based microfluidic devices are inexpensive, portable, easy to use, and require no external equipment to operate. As a result, they hold great promise as a platform for point-of-care diagnostics. In order to properly evaluate the utility and analytical performance of paper-based devices, suitable methods must be developed to ensure their manufacture is reproducible and at a scale that is appropriate for laboratory settings. In this manuscript, a method to fabricate a general device architecture that can be used for paper-based immunoassays is described. We use a form of additive manufacturing (multi-layer lamination) to prepare devices that comprise multiple layers of patterned paper and patterned adhesive. In addition to demonstrating the proper use of these three-dimensional paper-based microfluidic devices with an immunoassay for human chorionic gonadotropin (hCG), errors in the manufacturing process that may result in device failures are discussed. We expect this approach to manufacturing paper-based devices will find broad utility in the development of analytical applications designed specifically for limited-resource settings.

Sacrificial template method of fabricating a nanotube

DOEpatents

Yang, Peidong [Berkeley, CA; He, Rongrui [Berkeley, CA; Goldberger, Joshua [Berkeley, CA; Fan, Rong [El Cerrito, CA; Wu, Yi-Ying [Albany, CA; Li, Deyu [Albany, CA; Majumdar, Arun [Orinda, CA

2007-05-01

Methods of fabricating uniform nanotubes are described in which nanotubes were synthesized as sheaths over nanowire templates, such as using a chemical vapor deposition process. For example, single-crystalline zinc oxide (ZnO) nanowires are utilized as templates over which gallium nitride (GaN) is epitaxially grown. The ZnO templates are then removed, such as by thermal reduction and evaporation. The completed single-crystalline GaN nanotubes preferably have inner diameters ranging from 30 nm to 200 nm, and wall thicknesses between 5 and 50 nm. Transmission electron microscopy studies show that the resultant nanotubes are single-crystalline with a wurtzite structure, and are oriented along the <001> direction. The present invention exemplifies single-crystalline nanotubes of materials with a non-layered crystal structure. Similar "epitaxial-casting" approaches could be used to produce arrays and single-crystalline nanotubes of other solid materials and semiconductors. Furthermore, the fabrication of multi-sheath nanotubes are described as well as nanotubes having multiple longitudinal segments.

Method of fabricating a solar cell

DOEpatents

Pass, Thomas; Rogers, Robert

2016-02-16

Methods of fabricating solar cells are described. A porous layer may be formed on a surface of a substrate, the porous layer including a plurality of particles and a plurality of voids. A solution may be dispensed into one or more regions of the porous layer to provide a patterned composite layer. The substrate may then be heated.

Method of fabricating a solar cell

DOEpatents

Pass, Thomas; Rogers, Robert

2014-02-25

Methods of fabricating solar cells are described. A porous layer may be formed on a surface of a substrate, the porous layer including a plurality of particles and a plurality of voids. A solution may be dispensed into one or more regions of the porous layer to provide a patterned composite layer. The substrate may then be heated.

Layer-by-layer strippable Ag multilayer films fabricated by modular assembly.

PubMed

Li, Yan; Chen, Xiaoyan; Li, Qianqian; Song, Kai; Wang, Shihui; Chen, Xiaoyan; Zhang, Kai; Fu, Yu; Jiao, Yong-Hua; Sun, Ting; Liu, Fu-Chun; Han, En-Hou

2014-01-21

We have developed a new method to fabricate multilayer films, which uses prepared thin films as modular blocks and transfer as operation mode to build up multilayer structures. In order to distinguish it from the in situ fabrication manner, this method is called modular assembly in this study. On the basis of such concept, we have fabricated a multilayer film using the silver mirror film as the modular block and poly(lactic acid) as the transfer tool. Due to the special double-layer structure of the silver mirror film, the resulting multilayer film had a well-defined stratified architecture with alternate porous/compact layers. As a consequence of the distinct structure, the interaction between the adjacent layers was so weak that the multilayer film could be layer-by-layer stripped. In addition, the top layer in the film could provide an effective protection on the morphology and surface property of the underlying layers. This suggests that if the surface of the film was deteriorated, the top layer could be peeled off and the freshly exposed surface would still maintain the original function. The successful preparation of the layer-by-layer strippable silver multilayer demonstrates that modular assembly is a feasible and effective method to build up multilayer films capable of creating novel and attractive micro/nanostructures, having great potential in the fabrication of nanodevices and coatings.

Micropatterning of poly(dimethylsiloxane) using a photoresist lift-off technique for selective electrical insulation of microelectrode arrays

PubMed Central

Park, Jaewon; Kim, Hyun Soo; Han, Arum

2009-01-01

A poly(dimethylsiloxane) (PDMS) patterning method based on a photoresist lift-off technique to make an electrical insulation layer with selective openings is presented. The method enables creating PDMS patterns with small features and various thicknesses without any limitation in the designs and without the need for complicated processes or expensive equipments. Patterned PDMS layers were created by spin-coating liquid phase PDMS on top of a substrate having sacrificial photoresist patterns, followed by a photoresist lift-off process. The thickness of the patterned PDMS layers could be accurately controlled (6.5–24 µm) by adjusting processing parameters such as PDMS spin-coating speeds, PDMS dilution ratios, and sacrificial photoresist thicknesses. PDMS features as small as 15 µm were successfully patterned and the effects of each processing parameter on the final patterns were investigated. Electrical resistance tests between adjacent electrodes with and without the insulation layer showed that the patterned PDMS layer functions properly as an electrical insulation layer. Biocompatibility of the patterned PDMS layer was confirmed by culturing primary neuron cells on top of the layer for up to two weeks. An extensive neuronal network was successfully formed, showing that this PDMS patterning method can be applied to various biosensing microdevices. The utility of this fabrication method was further demonstrated by successfully creating a patterned electrical insulation layer on flexible substrates containing multi-electrode arrays. PMID:19946385

Multi-layer laminate structure and manufacturing method

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

Keenihan, James R; Cleereman, Robert J; Eurich, Gerald

2012-04-24

The present invention is premised upon a multi-layer laminate structure and method of manufacture, more particularly to a method of constructing the multi-layer laminate structure utilizing a laminate frame and at least one energy activated flowable polymer.

Multi-layer laminate structure and manufacturing method

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

Keenihan, James R.; Cleereman, Robert J.; Eurich, Gerald

2013-01-29

The present invention is premised upon a multi-layer laminate structure and method of manufacture, more particularly to a method of constructing the multi-layer laminate structure utilizing a laminate frame and at least one energy activated flowable polymer.

Characterization of multiaxial warp knit composites

NASA Technical Reports Server (NTRS)

Dexter, H. Benson; Hasko, Gregory H.; Cano, Roberto J.

1991-01-01

The objectives were to characterize the mechanical behavior and damage tolerance of two multiaxial warp knit fabrics to determine the acceptability of these fabrics for high performance composite applications. The tests performed included compression, tension, open hole compression, compression after impact and compression-compression fatigue. Tests were performed on as-fabricated fabrics and on multi-layer fabrics that were stitched together with either carbon or Kevlar stitching yarn. Results of processing studies for vacuum impregnation with Hercules 3501-6 epoxy resin and pressure impregnation with Dow Tactix 138/H41 epoxy resin and British Petroleum BP E905L epoxy resin are presented.

Making Complex Electrically Conductive Patterns on Cloth

NASA Technical Reports Server (NTRS)

Chu, Andrew; Fink, Patrick W.; Dobbins, Justin A.; Lin, Greg Y.; Scully, Robert C.; Trevino, Robert

2008-01-01

A method for automated fabrication of flexible, electrically conductive patterns on cloth substrates has been demonstrated. Products developed using this method, or related prior methods, are instances of a technology known as 'e-textiles,' in which electrically conductive patterns ar formed in, and on, textiles. For many applications, including high-speed digital circuits, antennas, and radio frequency (RF) circuits, an e-textile method should be capable of providing high surface conductivity, tight tolerances for control of characteristic impedances, and geometrically complex conductive patterns. Unlike prior methods, the present method satisfies all three of these criteria. Typical patterns can include such circuit structures as RF transmission lines, antennas, filters, and other conductive patterns equivalent to those of conventional printed circuits. The present method overcomes the limitations of the prior methods for forming the equivalent of printed circuits on cloth. A typical fabrication process according to the present method involves selecting the appropriate conductive and non-conductive fabric layers to build the e-textile circuit. The present method uses commercially available woven conductive cloth with established surface conductivity specifications. Dielectric constant, loss tangent, and thickness are some of the parameters to be considered for the non-conductive fabric layers. The circuit design of the conductive woven fabric is secured onto a non-conductive fabric layer using sewing, embroidery, and/or adhesive means. The portion of the conductive fabric that is not part of the circuit is next cut from the desired circuit using an automated machine such as a printed-circuit-board milling machine or a laser cutting machine. Fiducials can be used to align the circuit and the cutting machine. Multilayer circuits can be built starting with the inner layer and using conductive thread to make electrical connections between layers.

Method of freeform fabrication by selective gelation of powder suspensions

DOEpatents

Baskaran, S.; Graff, G.L.

1997-12-09

The present invention is a novel method for freeform fabrication. Specifically, the method of solid freeform fabrication has the steps of: (a) preparing a slurry by mixing powder particles with a suspension medium and a gelling polysaccharide; (b) making a layer by depositing an amount of said powder slurry in a confined region; (c) hardening a selected portion of the layer by applying a gelling agent to the selected portion; and (d) repeating steps (b) and (c) to make successive layers and forming a layered object. In many applications, it is desirable to remove unhardened material followed by heating to remove gellable polysaccharide then sintering. 2 figs.

Method of freeform fabrication by selective gelation of powder suspensions

DOEpatents

Baskaran, Suresh; Graff, Gordon L.

1997-01-01

The present invention is a novel method for freeform fabrication. Specifically, the method of solid freeform fabrication has the steps of: (a) preparing a slurry by mixing powder particles with a suspension medium and a gelling polysaccharide; (b) making a layer by depositing an amount of said powder slurry in a confined region; (c) hardening a selected portion of the layer by applying a gelling agent to the selected portion; and (d) repeating steps (b) and (c) to make successive layers and forming a layered object. In many applications, it is desirable to remove unhardened material followed by heating to remove gellable polysaccharide then sintering.

Multi-electrolyte-step anodic aluminum oxide method for the fabrication of self-organized nanochannel arrays

PubMed Central

2012-01-01

Nanochannel arrays were fabricated by the self-organized multi-electrolyte-step anodic aluminum oxide [AAO] method in this study. The anodization conditions used in the multi-electrolyte-step AAO method included a phosphoric acid solution as the electrolyte and an applied high voltage. There was a change in the phosphoric acid by the oxalic acid solution as the electrolyte and the applied low voltage. This method was used to produce self-organized nanochannel arrays with good regularity and circularity, meaning less power loss and processing time than with the multi-step AAO method. PMID:22333268

Method to fabricate high performance tubular solid oxide fuel cells

DOEpatents

Chen, Fanglin; Yang, Chenghao; Jin, Chao

2013-06-18

In accordance with the present disclosure, a method for fabricating a solid oxide fuel cell is described. The method includes forming an asymmetric porous ceramic tube by using a phase inversion process. The method further includes forming an asymmetric porous ceramic layer on a surface of the asymmetric porous ceramic tube by using a phase inversion process. The tube is co-sintered to form a structure having a first porous layer, a second porous layer, and a dense layer positioned therebetween.

Design of electrochromic window technology with single and multi-color patterns

NASA Astrophysics Data System (ADS)

Kim, Sooyeun

The electrochromic window (ECW) technology has gained a lot of attention due to its current and potential applications for office, vehicle and aircraft windows. Center for Intelligent Materials and System (CIMS) at University of Washington has proposed the new design of an ECW for its high contrast, rapid switching speed and long cyclic lifetime. Three primary components of the ECW are an electrochromic (EC) layer, an ion conducting layer and an ion storage layer. A V2O5-TiO2 (V/Ti=70/30) film, fabricated by a sol-gel electrophoretic deposition, was proposed as an ion storage layer. The film was characterized by X-ray diffraction, a scanning probe microscope and impedance spectroscopy. Its optical and electrochemical properties were investigated. The poly-(3,3-dimethy1-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine) film was suggested as an EC layer. Its electropolymerization kinetics and optical and electrochemical properties were reported. The V2O 5-TiO2 film based ECW was successfully fabricated and examined. The ECW exhibited its high electrochromic contrast, rapid switching speed and long-term cyclic durability. Its contrast (Delta%T = Tmax-T min) was 68%T with a minimum transmittance of 1% at 580 nm wavelength. The ECW took five seconds for complete coloration, while it did four seconds for complete bleaching. Its asymmetric switching behavior was explained by modeling the ECW as a simple equivalent circuit. The cyclic durability of the ECW was measured over 150,000 cycles. It revealed the contrast degradation of only 2% at 580 nm wavelength. The ECW dimensions were scaled up to 300 x 300 mm2, demonstrating their high contrast and long-term electrochemical cycle stability. Multi-color pattern electrochromic window technology was considered to evolve toward higher definition devices. Patterning of electrodes was essential to fabricate multi-color pattern ECWs which required the separation of adjacent electrodes. New fabrication procedures to create a pattern electrode were challenged. Two monomers were selectively electropolymerized on the pattern electrode in order to display a set of colors. The successful construction of a two-color pattern ECW was based on the sandwich-type configuration.

Metal hierarchical patterning by direct nanoimprint lithography

PubMed Central

Radha, Boya; Lim, Su Hui; Saifullah, Mohammad S. M.; Kulkarni, Giridhar U.

2013-01-01

Three-dimensional hierarchical patterning of metals is of paramount importance in diverse fields involving photonics, controlling surface wettability and wearable electronics. Conventionally, this type of structuring is tedious and usually involves layer-by-layer lithographic patterning. Here, we describe a simple process of direct nanoimprint lithography using palladium benzylthiolate, a versatile metal-organic ink, which not only leads to the formation of hierarchical patterns but also is amenable to layer-by-layer stacking of the metal over large areas. The key to achieving such multi-faceted patterning is hysteretic melting of ink, enabling its shaping. It undergoes transformation to metallic palladium under gentle thermal conditions without affecting the integrity of the hierarchical patterns on micro- as well as nanoscale. A metallic rice leaf structure showing anisotropic wetting behavior and woodpile-like structures were thus fabricated. Furthermore, this method is extendable for transferring imprinted structures to a flexible substrate to make them robust enough to sustain numerous bending cycles. PMID:23446801

In Vitro Engineering of Vascularized Tissue Surrogates

PubMed Central

Sakaguchi, Katsuhisa; Shimizu, Tatsuya; Horaguchi, Shigeto; Sekine, Hidekazu; Yamato, Masayuki; Umezu, Mitsuo; Okano, Teruo

2013-01-01

In vitro scaling up of bioengineered tissues is known to be limited by diffusion issues, specifically a lack of vasculature. Here, we report a new strategy for preserving cell viability in three-dimensional tissues using cell sheet technology and a perfusion bioreactor having collagen-based microchannels. When triple-layer cardiac cell sheets are incubated within this bioreactor, endothelial cells in the cell sheets migrate to vascularize in the collagen gel, and finally connect with the microchannels. Medium readily flows into the cell sheets through the microchannels and the newly developed capillaries, while the cardiac construct shows simultaneous beating. When additional triple-layer cell sheets are repeatedly layered, new multi-layer construct spontaneously integrates and the resulting construct becomes a vascularized thick tissue. These results confirmed our method to fabricate in vitro vascularized tissue surrogates that overcomes engineered-tissue thickness limitations. The surrogates promise new therapies for damaged organs as well as new in vitro tissue models. PMID:23419835

Fabrication of amorphous IGZO thin film transistor using self-aligned imprint lithography with a sacrificial layer

NASA Astrophysics Data System (ADS)

Kim, Sung Jin; Kim, Hyung Tae; Choi, Jong Hoon; Chung, Ho Kyoon; Cho, Sung Min

2018-04-01

An amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistor (TFT) was fabricated by a self-aligned imprint lithography (SAIL) method with a sacrificial photoresist layer. The SAIL is a top-down method to fabricate a TFT using a three-dimensional multilayer etch mask having all pattern information for the TFT. The sacrificial layer was applied in the SAIL process for the purpose of removing the resin residues that were inevitably left when the etch mask was thinned by plasma etching. This work demonstrated that the a-IGZO TFT could be fabricated by the SAIL process with the sacrificial layer. Specifically, the simple fabrication process utilized in this study can be utilized for the TFT with a plasma-sensitive semiconductor such as the a-IGZO and further extended for the roll-to-roll TFT fabrication.

Flexible fabrication of multi-scale integrated 3D periodic nanostructures with phase mask

NASA Astrophysics Data System (ADS)

Yuan, Liang Leon

Top-down fabrication of artificial nanostructures, especially three-dimensional (3D) periodic nanostructures, that forms uniform and defect-free structures over large area with the advantages of high throughput and rapid processing and in a manner that can further monolithically integrate into multi-scale and multi-functional devices is long-desired but remains a considerable challenge. This thesis study advances diffractive optical element (DOE) based 3D laser holographic nanofabrication of 3D periodic nanostructures and develops new kinds of DOEs for advanced diffracted-beam control during the fabrication. Phase masks, as one particular kind of DOE, are a promising direction for simple and rapid fabrication of 3D periodic nanostructures by means of Fresnel diffraction interference lithography. When incident with a coherent beam of light, a suitable phase mask (e.g. with 2D nano-grating) can create multiple diffraction orders that are inherently phase-locked and overlap to form a 3D light interference pattern in the proximity of the DOE. This light pattern is typically recorded in photosensitive materials including photoresist to develop into 3D photonic crystal nanostructure templates. Two kinds of advanced phase masks were developed that enable delicate phase control of multiple diffraction beams. The first exploits femtosecond laser direct writing inside fused silica to assemble multiple (up to nine) orthogonally crossed (2D) grating layers, spaced on Talbot planes to overcome the inherent weak diffraction efficiency otherwise found in low-contrast volume gratings. A systematic offsetting of orthogonal grating layers to establish phase offsets over 0 to pi/2 range provided precise means for controlling the 3D photonic crystal structure symmetry between body centered tetragonal (BCT) and woodpile-like tetragonal (wTTR). The second phase mask consisted of two-layered nanogratings with small sub-wavelength grating periods and phase offset control. That was designed with isotropic properties attractive for generating a complete photonic band gap (PBG). An isolation layer was used between adjacent polymer layers to offer a reversal coating for sample preparation of scanning electron microscopy (SEM) imaging and top surface planarization. Electron beam lithography has been employed to fabricate a multi-level nano-grating phase mask that produces a diamond-like 3D nanostructure via phase mask lithography, promising for creating photonic crystal (PC) templates that can be inverted with high-index materials and form a complete PBG at telecommunication wavelengths. A laser scanning holographic method for 3D exposure in thick photoresist is introduced that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form highly uniform 3D nanostructure with beam size scaled to small 200 microm diameter. Further direct-write holography demonstrates monolithical writing of multi-scale lab-on-a-chip with multiple functionalities including on-chip integrated fluorescence. Various 3D periodic nanostructures are demonstrated over a 15 mmx15 mm area, through full 40 microm photoresist thickness and with uniform structural and optical properties revealed by focused ion beam (FIB) milling, SEM imaging and stopband measures. The lateral and axial periods scale from respective 1500 nm to 570 nm and 9.2 microm to 1.2 microm to offer a Gamma-Z stopband at 1.5 microm. Overall, laser scanning is presented as a facile means to embed 3D PC nanostructure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems.

Fabrication and characterization of gels with integrated channels using 3D printing with microfluidic nozzle for tissue engineering applications.

PubMed

Attalla, R; Ling, C; Selvaganapathy, P

2016-02-01

The lack of a simple and effective method to integrate vascular network with engineered scaffolds and tissue constructs remains one of the biggest challenges in true 3D tissue engineering. Here, we detail the use of a commercially available, low-cost, open-source 3D printer modified with a microfluidic print-head in order to develop a method for the generation of instantly perfusable vascular network integrated with gel scaffolds seeded with cells. The print-head features an integrated coaxial nozzle that allows the fabrication of hollow, calcium-polymerized alginate tubes that can be easily patterned using 3D printing techniques. The diameter of the hollow channel can be precisely controlled and varied between 500 μm - 2 mm by changing applied flow rates or print-head speed. These channels are integrated into gel layers with a thickness of 800 μm - 2.5 mm. The structural rigidity of these constructs allows the fabrication of multi-layered structures without causing the collapse of hollow channels in lower layers. The 3D printing method was fully characterized at a range of operating speeds (0-40 m/min) and corresponding flow rates (1-30 mL/min) were identified to produce precise definition. This microfluidic design also allows the incorporation of a wide range of scaffold materials as well as biological constituents such as cells, growth factors, and ECM material. Media perfusion of the channels causes a significant viability increase in the bulk of cell-laden structures over the long-term. With this setup, gel constructs with embedded arrays of hollow channels can be created and used as a potential substitute for blood vessel networks.

Addressable multi-nozzle electrohydrodynamic jet printing with high consistency by multi-level voltage method

NASA Astrophysics Data System (ADS)

Pan, Yanqiao; Huang, YongAn; Guo, Lei; Ding, Yajiang; Yin, Zhouping

2015-04-01

It is critical and challenging to achieve the individual jetting ability and high consistency in multi-nozzle electrohydrodynamic jet printing (E-jet printing). We proposed multi-level voltage method (MVM) to implement the addressable E-jet printing using multiple parallel nozzles with high consistency. The fabricated multi-nozzle printhead for MVM consists of three parts: PMMA holder, stainless steel capillaries (27G, outer diameter 400 μm) and FR-4 extractor layer. The key of MVM is to control the maximum meniscus electric field on each nozzle. The individual jetting control can be implemented when the rings under the jetting nozzles are 0 kV and the other rings are 0.5 kV. The onset electric field for each nozzle is ˜3.4 kV/mm by numerical simulation. Furthermore, a series of printing experiments are performed to show the advantage of MVM in printing consistency than the "one-voltage method" and "improved E-jet method", by combination with finite element analyses. The good dimension consistency (274μm, 276μm, 280μm) and position consistency of the droplet array on the hydrophobic Si substrate verified the enhancements. It shows that MVM is an effective technique to implement the addressable E-jet printing with multiple parallel nozzles in high consistency.

Method of fabrication of supported liquid membranes

DOEpatents

Luebke, David R.; Hong, Lei; Myers, Christina R.

2015-11-17

Method for the fabrication of a supported liquid membrane having a dense layer in contact with a porous layer, and a membrane liquid layer within the interconnected pores of the porous layer. The dense layer is comprised of a solidified material having an average pore size less than or equal to about 0.1 nanometer, while the porous layer is comprised of a plurality of interconnected pores and has an average pore size greater than 10 nanometers. The supported liquid membrane is fabricated through the preparation of a casting solution of a membrane liquid and a volatile solvent. A pressure difference is established across the dense layer and porous layer, the casting solution is applied to the porous layer, and the low viscosity casting solution is drawn toward the dense layer. The volatile solvent is evaporated and the membrane liquid precipitates, generating a membrane liquid layer in close proximity to the dense layer.

Developing core-shell upconversion nanoparticles for optical encoding

NASA Astrophysics Data System (ADS)

Huang, Kai

Lanthanide-doped upconversion nanoparticles (UCNPs) are an emerging class of luminescent materials that emit UV or visible light under near infra-red (NIR) excitations, thereby possessing a large anti-Stokes shift property. Also considering their sharp emission bands, excellent photo- and chemical stability, and almost zero auto-fluorescence of their NIR excitation, UCNPs are advantageous for optical encoding. Fabricating core-shell structured UCNPs provides a promising strategy to tune and enhance their upconverting luminescence. However, the energy transfer between core and shell had been rarely studied. Moreover, this strategy had been limited by the difficulty of coating thick shells onto the large cores of UCNPs. To overcome these constraints, the overall aim of this project is to study the inter-layers energy transfer in core-shell UCNPs and to develop an approach for coating thicker shell onto the core UCNPs, in order to fabricate UCNPs with enhanced and tunable luminescence for optical encoding. The strategy for encapsulating UCNPs into hydrogel droplet to fabricate multi-color bead barcodes has also been developed. Firstly, to study the inter-layers energy transfer between the core and shell of coreshell UCNPs, the activator and sensitizer ions were separately doped in the core or shell by fabricating NaYF4:Er NaYF4:Yb and NaYF4:Yb NaYF4:Er UCNPs. This eliminated the intra-layer energy transfer, resulting in a luminescence that is solely based on the energy transfer between layers, which facilitated the study of inter-layers energy transfer. The results demonstrated that the NaYF4:Yb NaYF4:Er structure, with sensitizer ions doped in the core, was preferable because of the strong luminescence, through minimizing the cross relaxations between Er3+ and Yb3+ and the surface quenching. Based on these information, a strategy of enhancing and tuning upconversion luminescence of core-shell UCNPs by accumulating sensitizer in the core has been developed. Next, a strategy of coating a thick shell by lutetium doping has been developed. With a smaller ion radius compared to Y3+, when Lu3+ partially replace Y3+ in the NaYF4 UCNPs during nanoparticle synthesis, nucleation process is suppressed and the growth process is promoted, which are favorable for increasing the nanoparticle size and coating a thicker shell onto the core UCNPs. Through the rational doping of Lu3+, core UCNPs with bigger sizes and enhanced luminescence were produced. Using NaLuF4 as the shell material, shells with tremendous thickness were coated onto core UCNPs, with the shell/core ratio of up to 10:1. This led to the fabrication of multi-color UCNPs with well-designed core-shell structures with multiple layers and controllable thicknesses. Finally, a strategy of encapsulating these UCNPs to produce optically encoded micro-beads through high-throughput microfluidics has been developed. The hydrophobic UCNPs were first modified with Pluronic F127 to render them hydrophilic and uniformly distributed in the poly (ethylene glycol) diacrylate (PEGDA) hydrogel precursor. Droplets of the hydrogel precursor were formed in a microfluidic device and cross-linked into micro-beads under UV irradiation. Through encapsulation of multi-color UCNPs and by controlling their ratio, optically encoded multi-color micro-beads have been easily fabricated. These multi-color UCNPs and micro-bead barcodes have great potential for use in multiplexed bioimaging and detection.

Continuous blade coating for multi-layer large-area organic light-emitting diode and solar cell

NASA Astrophysics Data System (ADS)

Chen, Chun-Yu; Chang, Hao-Wen; Chang, Yu-Fan; Chang, Bo-Jie; Lin, Yuan-Sheng; Jian, Pei-Siou; Yeh, Han-Cheng; Chien, Hung-Ta; Chen, En-Chen; Chao, Yu-Chiang; Meng, Hsin-Fei; Zan, Hsiao-Wen; Lin, Hao-Wu; Horng, Sheng-Fu; Cheng, Yen-Ju; Yen, Feng-Wen; Lin, I.-Feng; Yang, Hsiu-Yuan; Huang, Kuo-Jui; Tseng, Mei-Rurng

2011-11-01

A continuous roll-to-roll compatible blade-coating method for multi-layers of general organic semiconductors is developed. Dissolution of the underlying film during coating is prevented by simultaneously applying heating from the bottom and gentle hot wind from the top. The solvent is immediately expelled and reflow inhibited. This method succeeds for polymers and small molecules. Uniformity is within 10% for 5 cm by 5 cm area with a mean value of tens of nanometers for both organic light-emitting diode (OLED) and solar cell structure with little material waste. For phosphorescent OLED 25 cd/A is achieved for green, 15 cd/A for orange, and 8 cd/A for blue. For fluorescent OLED 4.3 cd/A is achieved for blue, 9 cd/A for orange, and 6.9 cd/A for white. For OLED with 2 cm by 3 cm active area, the luminance variation is within 10%. Power conversion efficiency of 4.1% is achieved for polymer solar cell, similar to spin coating using the same materials. Very-low-cost and high-throughput fabrication of efficient organic devices is realized by the continuous blade-only method.

Methods of Fabricating a Layer of Metallic Glass-Based Material Using Immersion and Pouring Techniques

NASA Technical Reports Server (NTRS)

Hofmann, Douglas (Inventor)

2015-01-01

Systems and methods in accordance with embodiments of the invention implement layers of metallic glass-based materials. In one embodiment, a method of fabricating a layer of metallic glass includes: applying a coating layer of liquid phase metallic glass to an object, the coating layer being applied in a sufficient quantity such that the surface tension of the liquid phase metallic glass causes the coating layer to have a smooth surface; where the metallic glass has a critical cooling rate less than 1000 K/s; and cooling the coating layer of liquid phase metallic glass to form a layer of solid phase metallic glass.

Control and automation of multilayered integrated microfluidic device fabrication.

PubMed

Kipper, Sarit; Frolov, Ludmila; Guy, Ortal; Pellach, Michal; Glick, Yair; Malichi, Asaf; Knisbacher, Binyamin A; Barbiro-Michaely, Efrat; Avrahami, Dorit; Yavets-Chen, Yehuda; Levanon, Erez Y; Gerber, Doron

2017-01-31

Integrated microfluidics is a sophisticated three-dimensional (multi layer) solution for high complexity serial or parallel processes. Fabrication of integrated microfluidic devices requires soft lithography and the stacking of thin-patterned PDMS layers. Precise layer alignment and bonding is crucial. There are no previously reported standards for alignment of the layers, which is mostly performed using uncontrolled processes with very low alignment success. As a result, integrated microfluidics is mostly used in academia rather than in the many potential industrial applications. We have designed and manufactured a semiautomatic Microfluidic Device Assembly System (μDAS) for full device production. μDAS comprises an electrooptic mechanical system consisting of four main parts: optical system, smart media holder (for PDMS), a micropositioning xyzθ system and a macropositioning XY mechanism. The use of the μDAS yielded valuable information regarding PDMS as the material for device fabrication, revealed previously unidentified errors, and enabled optimization of a robust fabrication process. In addition, we have demonstrated the utilization of the μDAS technology for fabrication of a complex 3 layered device with over 12 000 micromechanical valves and an array of 64 × 64 DNA spots on a glass substrate with high yield and high accuracy. We increased fabrication yield from 25% to about 85% with an average layer alignment error of just ∼4 μm. It also increased our protein expression yields from 80% to over 90%, allowing us to investigate more proteins per experiment. The μDAS has great potential to become a valuable tool for both advancing integrated microfluidics in academia and producing and applying microfluidic devices in the industry.

Fabrication and preliminary study of a biomimetic tri-layer tubular graft based on fibers and fiber yarns for vascular tissue engineering.

PubMed

Wu, Tong; Zhang, Jialing; Wang, Yuanfei; Li, Dandan; Sun, Binbin; El-Hamshary, Hany; Yin, Meng; Mo, Xiumei

2018-01-01

Designing a biomimetic and functional tissue-engineered vascular graft has been urgently needed for repairing and regenerating defected vascular tissues. Utilizing a multi-layered vascular scaffold is commonly considered an effective way, because multi-layered scaffolds can easily simulate the structure and function of natural blood vessels. Herein, we developed a novel tri-layer tubular graft consisted of Poly(L-lactide-co-caprolactone)/collagen (PLCL/COL) fibers and Poly(lactide-co-glycolide)/silk fibroin (PLGA/SF) yarns via a three-step electrospinning method. The tri-layer vascular graft consisted of PLCL/COL aligned fibers in inner layer, PLGA/SF yarns in middle layer, and PLCL/COL random fibers in outer layer. Each layer possessed tensile mechanical strength and elongation, and the entire tubular structure provided tensile and compressive supports. Furthermore, the human umbilical vein endothelial cells (HUVECs) and smooth muscle cells (SMCs) proliferated well on the materials. Fluorescence staining images demonstrated that the axially aligned PLCL/COL fibers prearranged endothelium morphology in lumen and the circumferential oriented PLGA/SF yarns regulated SMCs organization along the single yarns. The outside PLCL/COL random fibers performed as the fixed layer to hold the entire tubular structure. The in vivo results showed that the tri-layer vascular graft supported cell infiltration, scaffold biodegradation and abundant collagen production after subcutaneous implantation for 10weeks, revealing the optimal biocompatibility and tissue regenerative capability of the tri-layer graft. Therefore, the specially designed tri-layer vascular graft will be beneficial to vascular reconstruction. Copyright © 2017. Published by Elsevier B.V.

High performance a-Si solar cells and new fabrication methods for a-Si solar cells

NASA Astrophysics Data System (ADS)

Nakano, S.; Kuwano, Y.; Ohnishi, M.

1986-12-01

The super chamber, a separated UHV reaction-chamber system has been developed. A conversion efficiency of 11.7% was obtained for an a-Si solar cell using a high-quality i-layer deposited by the super chamber, and a p-layer fabricated by a photo-CVD method. As a new material, amorphous superlattice-structure films were fabricated by the photo-CVD method for the first time. Superlattice structure p-layer a-Si solar cells were fabricated, and a conversion efficiency of 10.5% was obtained. For the fabrication of integrated type a-Si solar cell modules, a laser pattering method was investigated. A thermal analysis of the multilayer structure was done. It was confirmed that selective scribing for a-Si, TCO and metal film is possible by controlling the laser power density. Recently developed a-Si solar power generation systems and a-Si solar cell roofing tiles are also described.

All-Aluminum Thin Film Transistor Fabrication at Room Temperature.

PubMed

Yao, Rihui; Zheng, Zeke; Zeng, Yong; Liu, Xianzhe; Ning, Honglong; Hu, Shiben; Tao, Ruiqiang; Chen, Jianqiu; Cai, Wei; Xu, Miao; Wang, Lei; Lan, Linfeng; Peng, Junbiao

2017-02-23

Bottom-gate all-aluminum thin film transistors with multi conductor/insulator nanometer heterojunction were investigated in this article. Alumina (Al₂O₃) insulating layer was deposited on the surface of aluminum doping zinc oxide (AZO) conductive layer, as one AZO/Al₂O₃ heterojunction unit. The measurements of transmittance electronic microscopy (TEM) and X-ray reflectivity (XRR) revealed the smooth interfaces between ~2.2-nm-thick Al₂O₃ layers and ~2.7-nm-thick AZO layers. The devices were entirely composited by aluminiferous materials, that is, their gate and source/drain electrodes were respectively fabricated by aluminum neodymium alloy (Al:Nd) and pure Al, with Al₂O₃/AZO multilayered channel and AlO x :Nd gate dielectric layer. As a result, the all-aluminum TFT with two Al₂O₃/AZO heterojunction units exhibited a mobility of 2.47 cm²/V·s and an I on / I off ratio of 10⁶. All processes were carried out at room temperature, which created new possibilities for green displays industry by allowing for the devices fabricated on plastic-like substrates or papers, mainly using no toxic/rare materials.

Oxazine-based sensor for contaminant detection, fabrication method therefor, and uses thereof

DOEpatents

Nnanna, Agbai Agwu; Jalal, Ahmed Hasnian

2014-05-27

A sensor, a method for its fabrication, and a method for its use to detect contaminants, for example, ammonia, in stagnant and dynamic fluid media, especially liquid media. The sensor is an opto-chemical sensor that includes a polymer optical fiber, a sensing layer comprising oxazine 170 perchlorate on the polymer optical fiber, and a membrane layer on the sensing layer. The membrane layer is gas permeable and not permeable to the fluid in the fluid system, and moisture is entrapped by and between the sensing and membrane layers.

Multi-Layer E-Textile Circuits

NASA Technical Reports Server (NTRS)

Dunne, Lucy E.; Bibeau, Kaila; Mulligan, Lucie; Frith, Ashton; Simon, Cory

2012-01-01

Stitched e-textile circuits facilitate wearable, flexible, comfortable wearable technology. However, while stitched methods of e-textile circuits are common, multi-layer circuit creation remains a challenge. Here, we present methods of stitched multi-layer circuit creation using accessible tools and techniques.

Controllable 3D architectures of aligned carbon nanotube arrays by multi-step processes

NASA Astrophysics Data System (ADS)

Huang, Shaoming

2003-06-01

An effective way to fabricate large area three-dimensional (3D) aligned CNTs pattern based on pyrolysis of iron(II) phthalocyanine (FePc) by two-step processes is reported. The controllable generation of different lengths and selective growth of the aligned CNT arrays on metal-patterned (e.g., Ag and Au) substrate are the bases for generating such 3D aligned CNTs architectures. By controlling experimental conditions 3D aligned CNT arrays with different lengths/densities and morphologies/structures as well as multi-layered architectures can be fabricated in large scale by multi-step pyrolysis of FePc. These 3D architectures could have interesting properties and be applied for developing novel nanotube-based devices.

Compact cladding-pumped planar waveguide amplifier and fabrication method

DOEpatents

Bayramian, Andy J.; Beach, Raymond J.; Honea, Eric; Murray, James E.; Payne, Stephen A.

2003-10-28

A low-cost, high performance cladding-pumped planar waveguide amplifier and fabrication method, for deployment in metro and access networks. The waveguide amplifier has a compact monolithic slab architecture preferably formed by first sandwich bonding an erbium-doped core glass slab between two cladding glass slabs to form a multi-layer planar construction, and then slicing the construction into multiple unit constructions. Using lithographic techniques, a silver stripe is deposited and formed at a top or bottom surface of each unit construction and over a cross section of the bonds. By heating the unit construction in an oven and applying an electric field, the silver stripe is then ion diffused to increase the refractive indices of the core and cladding regions, with the diffusion region of the core forming a single mode waveguide, and the silver diffusion cladding region forming a second larger waveguide amenable to cladding pumping with broad area diodes.

Silicon Sheet Growth Development for the Large Area Sheet Task of the Low Cost Solar Array Project. Heat Exchanger Method - Ingot Casting Fixed Abrasive Method - Multi-Wire Slicing

NASA Technical Reports Server (NTRS)

Schmid, F.; Khattak, C. P.

1978-01-01

Solar cells fabricated from HEM cast silicon yielded up to 15% conversion efficiencies. This was achieved in spite of using unpurified graphite parts in the HEM furnace and without optimization of material or cell processing parameters. Molybdenum retainers prevented SiC formation and reduced carbon content by 50%. The oxygen content of vacuum cast HEM silicon is lower than typical Czochralski grown silicon. Impregnation of 45 micrometers diamonds into 7.5 micrometers copper sheath showed distortion of the copper layer. However, 12.5 micrometers and 15 micrometers copper sheath can be impregnated with 45 micrometers diamonds to a high concentration. Electroless nickel plating of wires impregnated only in the cutting edge showed nickel concentration around the diamonds. This has the possibility of reducing kerf. The high speed slicer fabricated can achieve higher speed and longer stroke with vibration isolation.

Two-step fabrication of single-layer rectangular SnSe flakes

NASA Astrophysics Data System (ADS)

Jiang, Jizhou; Wong, Calvin Pei Yu; Zou, Jing; Li, Shisheng; Wang, Qixing; Chen, Jianyi; Qi, Dianyu; Wang, Hongyu; Eda, Goki; Chua, Daniel H. C.; Shi, Yumeng; Zhang, Wenjing; Thye Shen Wee, Andrew

2017-06-01

Recent findings about ultrahigh thermoelectric performances in SnSe single crystals have stimulated research on this binary semiconductor material. Furthermore, single-layer SnSe is an interesting analogue of phosphorene, with potential applications in two-dimensional (2D) nanoelectronics. Although significant advances in the synthesis of SnSe nanocrystals have been made, fabrication of well-defined large-sized single-layer SnSe flakes in a facile way still remains a challenge. The growth of single-layer rectangular SnSe flakes with a thickness of ~6.8 Å and lateral dimensions of about 30 µm  ×  50 µm is demonstrated by a two-step synthesis method, where bulk rectangular SnSe flakes were synthesized first by a vapor transport deposition method followed by a nitrogen etching technique to fabricate single-layer rectangular SnSe flakes in an atmospheric pressure system. The as-obtained rectangular SnSe flakes exhibited a pure crystalline phase oriented along the a-axis direction. Field-effect transistor devices fabricated on individual single-layer rectangular SnSe flakes using gold electrodes exhibited p-doped ambipolar behavior and a hole mobility of about 0.16 cm2 V-1 s-1. This two-step fabrication method can be helpful for growing other similar 2D large-sized single-layer materials.

Towards seamlessly-integrated textile electronics: methods to coat fabrics and fibers with conducting polymers for electronic applications.

PubMed

Allison, Linden; Hoxie, Steven; Andrew, Trisha L

2017-06-29

Traditional textile materials can be transformed into functional electronic components upon being dyed or coated with films of intrinsically conducting polymers, such as poly(aniline), poly(pyrrole) and poly(3,4-ethylenedioxythiophene). A variety of textile electronic devices are built from the conductive fibers and fabrics thus obtained, including: physiochemical sensors, thermoelectric fibers/fabrics, heated garments, artificial muscles and textile supercapacitors. In all these cases, electrical performance and device ruggedness is determined by the morphology of the conducting polymer active layer on the fiber or fabric substrate. Tremendous variation in active layer morphology can be observed with different coating or dyeing conditions. Here, we summarize various methods used to create fiber- and fabric-based devices and highlight the influence of the coating method on active layer morphology and device stability.

Investigation of the shape transferability of nanoscale multi-tip diamond tools in the diamond turning of nanostructures

NASA Astrophysics Data System (ADS)

Luo, Xichun; Tong, Zhen; Liang, Yingchun

2014-12-01

In this article, the shape transferability of using nanoscale multi-tip diamond tools in the diamond turning for scale-up manufacturing of nanostructures has been demonstrated. Atomistic multi-tip diamond tool models were built with different tool geometries in terms of the difference in the tip cross-sectional shape, tip angle, and the feature of tool tip configuration, to determine their effect on the applied forces and the machined nano-groove geometries. The quality of machined nanostructures was characterized by the thickness of the deformed layers and the dimensional accuracy achieved. Simulation results show that diamond turning using nanoscale multi-tip tools offers tremendous shape transferability in machining nanostructures. Both periodic and non-periodic nano-grooves with different cross-sectional shapes can be successfully fabricated using the multi-tip tools. A hypothesis of minimum designed ratio of tool tip distance to tip base width (L/Wf) of the nanoscale multi-tip diamond tool for the high precision machining of nanostructures was proposed based on the analytical study of the quality of the nanostructures fabricated using different types of the multi-tip tools. Nanometric cutting trials using nanoscale multi-tip diamond tools (different in L/Wf) fabricated by focused ion beam (FIB) were then conducted to verify the hypothesis. The investigations done in this work imply the potential of using the nanoscale multi-tip diamond tool for the deterministic fabrication of period and non-periodic nanostructures, which opens up the feasibility of using the process as a versatile manufacturing technique in nanotechnology.

Low voltage electrowetting lenticular lens by using multilayer dielectric structure

NASA Astrophysics Data System (ADS)

Lee, Junsik; Kim, Junoh; Kim, Cheoljoong; Shin, Dooseub; Koo, Gyohyun; Sim, Jee Hoon; Won, Yong Hyub

2017-02-01

Lenticular type multi-view display is one of the most popular ways for implementing three dimensional display. This method has a simple structure and exhibits a high luminance. However, fabricating the lenticular lens is difficult because it requires optically complex calculations. 2D-3D conversion is also impossible due to the fixed shape of the lenticular lens. Electrowetting based liquid lenticular lens has a simple fabrication process compared to the solid lenticular lens and the focal length of the liquid lenticular lens can be changed by applying the voltage. 3D and 2D images can be observed with a convex and a flat lens state respectively. Despite these advantages, the electrowetting based liquid lenticular lens demands high driving voltage and low breakdown voltage with a single dielectric layer structure. A certain degree of thickness of the dielectric layer is essential for a uniform operation and a low degradation over time. This paper presents multilayer dielectric structure which results in low driving voltage and the enhanced dielectric breakdown. Aluminum oxide (Al2O3), silicon oxide (SiO2) and parylene C were selected as the multilayer insulators. The total thickness of the dielectric layer of all samples was the same. This method using the multilayer dielectric structure can achieve the lower operating voltage than when using the single dielectric layer. We compared the liquid lenticular lens with three kinds of the multilayer dielectric structure to one with the parylene C single dielectric layer in regard to operational characteristics such as the driving voltage and the dielectric breakdown.

Enhanced light extraction efficiency of GaN-based light-emittng diodes by nitrogen implanted current blocking layer

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

Kim, Yong Deok; Oh, Seung Kyu; Park, Min Joo

Highlights: • A nitrogen implanted current-blocking layer was successfully demonstrated. • Light-extraction efficiency and radiant intensity was increased by more than 20%. • Ion implantation was successfully implemented in GaN based light-emitting diodes. - Abstract: GaN-based light emitting diodes (LEDs) with a nitrogen implanted current-blocking layer (CBL) were successfully demonstrated for improving the light extraction efficiency (LEE) and radiant intensity. The LEE and radiant intensity of the LEDs with a shallow implanted CBL with nitrogen was greatly increased by more than 20% compared to that of a conventional LED without the CBL due to an increase in the effective currentmore » path, which reduces light absorption at the thick p-pad electrode. Meanwhile, deep implanted CBL with a nitrogen resulted in deterioration of the LEE and radiant intensity because of formation of crystal damage, followed by absorption of the light generated at the multi-quantum well(MQW). These results clearly suggest that ion implantation method, which is widely applied in the fabrication of Si based devices, can be successfully implemented in the fabrication of GaN based LEDs by optimization of implanted depth.« less

Selectively Enhanced UV-A Photoresponsivity of a GaN MSM UV Photodetector with a Step-Graded AlxGa1-xN Buffer Layer.

PubMed

Lee, Chang-Ju; Won, Chul-Ho; Lee, Jung-Hee; Hahm, Sung-Ho; Park, Hongsik

2017-07-21

The UV-to-visible rejection ratio is one of the important figure of merits of GaN-based UV photodetectors. For cost-effectiveness and large-scale fabrication of GaN devices, we tried to grow a GaN epitaxial layer on silicon substrate with complicated buffer layers for a stress-release. It is known that the structure of the buffer layers affects the performance of devices fabricated on the GaN epitaxial layers. In this study, we show that the design of a buffer layer structure can make effect on the UV-to-visible rejection ratio of GaN UV photodetectors. The GaN photodetector fabricated on GaN-on-silicon substrate with a step-graded Al x Ga -x N buffer layer has a highly-selective photoresponse at 365-nm wavelength. The UV-to-visible rejection ratio of the GaN UV photodetector with the step-graded Al x Ga 1-x N buffer layer was an order-of-magnitude higher than that of a photodetector with a conventional GaN/AlN multi buffer layer. The maximum photoresponsivity was as high as 5 × 10 - ² A/W. This result implies that the design of buffer layer is important for photoresponse characteristics of GaN UV photodetectors as well as the crystal quality of the GaN epitaxial layers.

Transitional analysis of organic thin color filter layers in displays during baking process using multi-speckle diffusing wave spectroscopy

NASA Astrophysics Data System (ADS)

Park, Baek Sung; Hyung, Kyung Hee; Oh, Gwi Jeong; Jung, Hyun Wook

2018-02-01

The color filter (CF) is one of the key components for improving the performance of TV displays such as liquid crystal display (LCD) and white organic light emitting diodes (WOLED). The profile defects like undercut during the fine fabrication processes for CF layers are inevitably generated through the UV exposure and development processes, however, these can be controlled through the baking process. In order to resolve the profile defects of CF layers, in this study, the real-time dynamic changes of CF layers are monitored during the baking process by changing components such as polymeric binder and acrylate. The motion of pigment particles in CF layers during baking is quantitatively interpreted using multi-speckle diffusing wave spectroscopy (MSDWS), in terms of the autocorrelation function and the characteristic time of α-relaxation.

Methods for making a multi-layer seal for electrochemical devices

DOEpatents

Chou, Yeong-Shyung [Richland, WA; Meinhardt, Kerry D [Kennewick, WA; Stevenson, Jeffry W [Richland, WA

2007-05-29

Multi-layer seals are provided that find advantageous use for reducing leakage of gases between adjacent components of electrochemical devices. Multi-layer seals of the invention include a gasket body defining first and second opposing surfaces and a compliant interlayer positioned adjacent each of the first and second surfaces. Also provided are methods for making and using the multi-layer seals, and electrochemical devices including said seals.

Method to fabricate layered material compositions

DOEpatents

Fleming, James G.; Lin, Shawn-Yu

2004-11-02

A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

Design and fabrication of MEMS devices using the integration of MUMPs, trench-refilled molding, DRIE and bulk silicon etching processes

NASA Astrophysics Data System (ADS)

Wu, Mingching; Fang, Weileun

2005-03-01

This work integrates multi-depth DRIE etching, trench-refilled molding, two poly-Si layers MUMPs and bulk releasing to improve the variety and performance of MEMS devices. In summary, the present fabrication process, named MOSBE II, has three merits. First, this process can monolithically fabricate and integrate poly-Si thin-film structures with different thicknesses and stiffnesses, such as the flexible spring and the stiff mirror plate. Second, multi-depth structures, such as vertical comb electrodes, are available from the DRIE processes. Third, a cavity under the micromachined device is provided by the bulk silicon etching process, so that a large out-of-plane motion is allowed. In application, an optical scanner driven by the self-aligned vertical comb actuator was demonstrated. The poly-Si micromachined components fabricated by MOSBE II can further integrate with the MUMPs devices to establish a more powerful MOEMS platform.

3D nanofabrication inside rapid prototyped microfluidic channels showcased by wet-spinning of single micrometre fibres.

PubMed

Lölsberg, Jonas; Linkhorst, John; Cinar, Arne; Jans, Alexander; Kuehne, Alexander J C; Wessling, Matthias

2018-05-01

Microfluidics is an established multidisciplinary research domain with widespread applications in the fields of medicine, biotechnology and engineering. Conventional production methods of microfluidic chips have been limited to planar structures, preventing the exploitation of truly three-dimensional architectures for applications such as multi-phase droplet preparation or wet-phase fibre spinning. Here the challenge of nanofabrication inside a microfluidic chip is tackled for the showcase of a spider-inspired spinneret. Multiphoton lithography, an additive manufacturing method, was used to produce free-form microfluidic masters, subsequently replicated by soft lithography. Into the resulting microfluidic device, a three-dimensional spider-inspired spinneret was directly fabricated in-chip via multiphoton lithography. Applying this unprecedented fabrication strategy, the to date smallest printed spinneret nozzle is produced. This spinneret resides tightly sealed, connecting it to the macroscopic world. Its functionality is demonstrated by wet-spinning of single-digit micron fibres through a polyacrylonitrile coagulation process induced by a water sheath layer. The methodology developed here demonstrates fabrication strategies to interface complex architectures into classical microfluidic platforms. Using multiphoton lithography for in-chip fabrication adopts a high spatial resolution technology for improving geometry and thus flow control inside microfluidic chips. The showcased fabrication methodology is generic and will be applicable to multiple challenges in fluid control and beyond.

Use of chemical-mechanical polishing for fabricating photonic bandgap structures

DOEpatents

Fleming, James G.; Lin, Shawn-Yu; Hetherington, Dale L.; Smith, Bradley K.

1999-01-01

A method is disclosed for fabricating a two- or three-dimensional photonic bandgap structure (also termed a photonic crystal, photonic lattice, or photonic dielectric structure). The method uses microelectronic integrated circuit (IC) processes to fabricate the photonic bandgap structure directly upon a silicon substrate. One or more layers of arrayed elements used to form the structure are deposited and patterned, with chemical-mechanical polishing being used to planarize each layer for uniformity and a precise vertical tolerancing of the layer. The use of chemical-mechanical planarization allows the photonic bandgap structure to be formed over a large area with a layer uniformity of about two-percent. Air-gap photonic bandgap structures can also be formed by removing a spacer material separating the arrayed elements by selective etching. The method is useful for fabricating photonic bandgap structures including Fabry-Perot resonators and optical filters for use at wavelengths in the range of about 0.2-20 .mu.m.

Analysis of the tunable asymmetric fiber F-P cavity for fiber strain sensor edge-filter demodulation

NASA Astrophysics Data System (ADS)

Chen, Haotao; Liang, Youcheng

2014-12-01

An asymmetric fiber (Fabry-Pérot, F-P) interferometric cavity with the good linearity and wide dynamic range was successfully designed based on the optical thin film characteristic matrix theory; by adjusting the material of two different thin metallic layers, the asymmetric fiber F-P interferometric cavity was fabricated by depositing the multi-layer thin films on the optical fiber's end face. The asymmetric F-P cavity has the extensive potential application. In this paper, the demodulation method for the wavelength shift of the fiber Bragg grating (FBG) sensor based on the F-P cavity is demonstrated, and a theoretical formula is obtained. And the experimental results coincide well with the computational results obtained from the theoretical model.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

NASA Astrophysics Data System (ADS)

Tang, Xiaoning; Tian, Mingwei; Qu, Lijun; Zhu, Shifeng; Guo, Xiaoqing; Han, Guangting; Sun, Kaikai; Hu, Xili; Wang, Yujiao; Xu, Xiaoqi

2014-10-01

Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric.

Composite metal foil and ceramic fabric materials

DOEpatents

Webb, B.J.; Antoniak, Z.I.; Prater, J.T.; DeSteese, J.G.

1992-03-24

The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed. 11 figs.

Method for the production of fabricated hollow microspheroids

DOEpatents

Wickramanayake, Shan; Luebke, David R.

2015-06-09

The method relates to the fabrication of a polymer microspheres comprised of an asymmetric layer surrounding a hollow interior. The fabricated hollow microsphere is generated from a nascent hollow microsphere comprised of an inner core of core fluid surrounded by a dope layer of polymer dope, where the thickness of the dope layer is at least 10% and less than 50% of the diameter of the inner core. The nascent hollow microsphere is exposed to a gaseous environment, generating a vitrified hollow microsphere, which is subsequently immersed in a coagulation bath. Solvent exchange produces a fabricated hollow microsphere comprised of a densified outer skin surrounding a macroporous inner layer, which surrounds a hollow interior. In an embodiment, the polymer is a polyimide or a polyamide-imide, and the non-solvent in the core fluid and the coagulation bath is water. The fabricated hollow microspheres are particularly suited as solvent supports for gas separation processes.

Method to control artifacts of microstructural fabrication

DOEpatents

Shul, Randy J.; Willison, Christi G.; Schubert, W. Kent; Manginell, Ronald P.; Mitchell, Mary-Anne; Galambos, Paul C.

2006-09-12

New methods for fabrication of silicon microstructures have been developed. In these methods, an etching delay layer is deposited and patterned so as to provide differential control on the depth of features being etched into a substrate material. Compensation for etching-related structural artifacts can be accomplished by proper use of such an etching delay layer.

Multi-layer electrode with nano-Li4Ti5O12 aggregates sandwiched between carbon nanotube and graphene networks for high power Li-ion batteries.

PubMed

Choi, Jin-Hoon; Ryu, Won-Hee; Park, Kyusung; Jo, Jeong-Dai; Jo, Sung-Moo; Lim, Dae-Soon; Kim, Il-Doo

2014-12-05

Self-aggregated Li4Ti5O12 particles sandwiched between graphene nanosheets (GNSs) and single-walled carbon nanotubes (SWCNTs) network are reported as new hybrid electrodes for high power Li-ion batteries. The multi-layer electrodes are fabricated by sequential process comprising air-spray coating of GNSs layer and the following electrostatic spray (E-spray) coating of well-dispersed colloidal Li4Ti5O12 nanoparticles, and subsequent air-spray coating of SWCNTs layer once again. In multi-stacked electrodes of GNSs/nanoporous Li4Ti5O12 aggregates/SWCNTs networks, GNSs and SWCNTs serve as conducting bridges, effectively interweaving the nanoporous Li4Ti5O12 aggregates, and help achieve superior rate capability as well as improved mechanical stability of the composite electrode by holding Li4Ti5O12 tightly without a binder. The multi-stacked electrodes deliver a specific capacity that maintains an impressively high capacity of 100 mA h g(-1) at a high rate of 100C even after 1000 cycles.

Ballistic Impact Resistance of Multi-Layer Textile Fabrics

DTIC Science & Technology

1981-10-01

REBOT (NNOLA, NVAR). the first array contains the vector of forces externally applied to the ’ top surface of the layer under consideration, while the...array REBOT (NNOLA, NVAR) contains the forces externally applied to the lower surface of the array. Initially all the elements of each of the two arrays...Qodes in a layer, the contents of array REBOT are now replaced with those of array RETOP in preparation for the repetition of the same calculations for

Multi-wavelength VCSEL arrays using high-contrast gratings

NASA Astrophysics Data System (ADS)

Haglund, Erik; Gustavsson, Johan S.; Sorin, Wayne V.; Bengtsson, Jörgen; Fattal, David; Haglund, Àsa; Tan, Michael; Larsson, Anders

2017-02-01

The use of a high-contrast grating (HCG) as the top mirror in a vertical-cavity surface-emitting laser (VCSEL) allows for setting the resonance wavelength by the grating parameters in a post-epitaxial growth fabrication process. Using this technique, we demonstrate electrically driven multi-wavelength VCSEL arrays at 980 nm wavelength. The VCSELs are GaAs-based and the suspended GaAs HCGs were fabricated using electron-beam lithography, dry etching and selective removal of an InGaP sacrificial layer. The air-coupled cavity design enabled 4-channel arrays with 5 nm wavelength spacing and sub-mA threshold currents thanks to the high HCG reflectance.

Planarization of metal films for multilevel interconnects

DOEpatents

Tuckerman, D.B.

1985-06-24

In the fabrication of multilevel integrated circuits, each metal layer is planarized by heating to momentarily melt the layer. The layer is melted by sweeping lase pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

Planarization of metal films for multilevel interconnects

DOEpatents

Tuckerman, David B.

1987-01-01

In the fabrication of multilevel integrated circuits, each metal layer is anarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

Planarization of metal films for multilevel interconnects

DOEpatents

Tuckerman, David B.

1989-01-01

In the fabrication of multilevel integrated circuits, each metal layer is anarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

Planarization of metal films for multilevel interconnects

DOEpatents

Tuckerman, D.B.

1985-08-23

In the fabrication of multilevel integrated circuits, each metal layer is planarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

Planarization of metal films for multilevel interconnects

DOEpatents

Tuckerman, D.B.

1989-03-21

In the fabrication of multilevel integrated circuits, each metal layer is planarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration. 6 figs.

Improvement of multi-level resistive switching characteristics in solution-processed AlO x -based non-volatile resistive memory using microwave irradiation

NASA Astrophysics Data System (ADS)

Kim, Seung-Tae; Cho, Won-Ju

2018-01-01

We fabricated a resistive random access memory (ReRAM) device on a Ti/AlO x /Pt structure with solution-processed AlO x switching layer using microwave irradiation (MWI), and demonstrated multi-level cell (MLC) operation. To investigate the effect of MWI power on the MLC characteristics, post-deposition annealing was performed at 600-3000 W after AlO x switching layer deposition, and the MLC operation was compared with as-deposited (as-dep) and conventional thermally annealing (CTA) treated devices. All solution-processed AlO x -based ReRAM devices exhibited bipolar resistive switching (BRS) behavior. We found that these devices have four-resistance states (2 bits) of MLC operation according to the modulation of the high-resistance state (HRSs) through reset voltage control. Particularly, compared to the as-dep and CTA ReRAM devices, the MWI-treated ReRAM devices showed a significant increase in the memory window and stable endurance for multi-level operation. Moreover, as the MWI power increased, excellent MLC characteristics were exhibited because the resistance ratio between each resistance state was increased. In addition, it exhibited reliable retention characteristics without deterioration at 25 °C and 85 °C for 10 000 s. Finally, the relationship between the chemical characteristics of the solution-processed AlO x switching layer and BRS-based multi-level operation according to the annealing method and MWI power was investigated using x-ray photoelectron spectroscopy.

Friction Freeform Fabrication of Superalloy Inconel 718: Prospects and Problems

NASA Astrophysics Data System (ADS)

Dilip, J. J. S.; Janaki Ram, G. D.

2014-01-01

Friction Freeform Fabrication is a new solid-state additive manufacturing process. The present investigation reports a detailed study on the prospects of this process for additive part fabrication in superalloy Inconel 718. Using a rotary friction welding machine and employing alloy 718 consumable rods in solution treated condition, cylindrical-shaped multi-layer friction deposits (10 mm diameter) were successfully produced. In the as-deposited condition, the deposits showed very fine grain size with no grain boundary δ phase. The deposits responded well to direct aging and showed satisfactory room-temperature tensile properties. However, their stress rupture performance was unsatisfactory because of their layered microstructure with very fine grain size and no grain boundary δ phase. The problem was overcome by heat treating the deposits first at 1353 K (1080 °C) (for increasing the grain size) and then at 1223 K (950 °C) (for precipitating the δ phase). Overall, the current study shows that Friction Freeform Fabrication is a very useful process for additive part fabrication in alloy 718.

Hydrothermal growth of ZnO nanowires on flexible fabric substrates

NASA Astrophysics Data System (ADS)

Hong, Gwang-Wook; Yun, Sang-Ho; Kim, Joo-Hyung

2016-04-01

ZnO nanowires (NWs) would provide significant enhancement in sensitivity due to high surface to volume ratio. We investigated the first methodical study on the quantitative relationship between the process parameters of solution concentration ratio, structure, and physical and properties of ZnO NWs grown on different flexible fabric surfaces. To develop a fundamental following concerning various substrates, we controlled the growth speed of ZnO NWs and nanowires on cotton surface with easy and moderate cost fabrication method. Using ammonium hydroxide as the reactant with zinc nitrate hexahydrate, ZnO NWs layer have been grown on metal layers, instead of seed layer. ZnO NWs fabrication was done on different fabric substrates such as wool, nylon and polypropylene (PP). After the ZnO NWs grown to each substrates, we coated insulating layer with polyurethane (PU) and ethyl cellulose for prevent external intervention. Detailed electrical characterization was subsequently performed to reveal the working characteristics of the hybrid fabric. For electrical verification of fabricated ZnO NWs, we implemented measurement impact test and material properties with FFT analyzer and LCR meter.

Coupling of carboxylic groups onto the surface of polystyrene parts during fused filament fabrication

NASA Astrophysics Data System (ADS)

Nagel, Jürgen; Zimmermann, Philipp; Schubert, Oliver; Simon, Frank; Schlenstedt, Kornelia

2017-11-01

A method for the fabrication of polystyrene parts, modified with carboxylic groups during Fused Filament Fabrication (FFF), is being introduced. This method is based on the application of a thin layer of a reactive polymer carrying carboxylic groups on a substrate surface. A polystyrene film is printed on top of this layer. During contact between the hot melt and the reactive layer, a Friedel-Crafts type acylation using a green catalyst takes place, which attaches the reactive polymer to the polystyrene surface. The modified surface is homogeneous, hydrophilic and able to bind copper ions. The method could be used to fabricate unique parts of polystyrene with tailored surface functionalisation. It could be applied for laboratory use, e.g. for the manufacture of lab-on-a-chip devices.

Combining a multi deposition multi annealing technique with a scavenging (Ti) to improve the high-k/metal gate stack performance for a gate-last process

NASA Astrophysics Data System (ADS)

ShuXiang, Zhang; Hong, Yang; Bo, Tang; Zhaoyun, Tang; Yefeng, Xu; Jing, Xu; Jiang, Yan

2014-10-01

ALD HfO2 films fabricated by a novel multi deposition multi annealing (MDMA) technique are investigated, we have included samples both with and without a Ti scavenging layer. As compared to the reference gate stack treated by conventional one-time deposition and annealing (D&A), devices receiving MDMA show a significant reduction in leakage current. Meanwhile, EOT growth is effectively controlled by the Ti scavenging layer. This improvement strongly correlates with the cycle number of D&A (while keeping the total annealing time and total dielectrics thickness the same). Transmission electron microscope and energy-dispersive X-ray spectroscopy analysis suggests that oxygen incorporation into both the high-k film and the interfacial layer is likely to be responsible for the improvement of the device. This novel MDMA is promising for the development of gate stack technology in a gate last integration scheme.

Design, simulation and testing of a novel radial multi-pole multi-layer magnetorheological brake

NASA Astrophysics Data System (ADS)

Wu, Jie; Li, Hua; Jiang, Xuezheng; Yao, Jin

2018-02-01

This paper deals with design, simulation and experimental testing of a novel radial multi-pole multi-layer magnetorheological (MR) brake. This MR brake has an innovative structural design with superposition principle of two magnetic fields generated by the inner coils and the outer coils. The MR brake has several media layers of magnetorheological (MR) fluid located between the inner coils and the outer coils, and it can provide higher torque and higher torque density than conventional single-disk or multi-disk or multi-pole single-layer MR brakes can. In this paper, a brief introduction to the structure of the proposed MR brake was given first. Then, theoretical analysis of the magnetic circuit and the braking torque was conducted. In addition, a 3D electromagnetic model of the MR brake was developed to simulate and examine the magnetic flux intensity and corresponding braking torque. A prototype of the brake was fabricated and several tests were carried out to validate its torque capacity. The results show that the proposed MR brake can produce a maximum braking torque of 133 N m and achieve a high torque density of 25.0 kN m-2, a high torque range of 42 and a high torque-to-power ratio of 0.95 N m W-1.

Heat resistive dielectric multi-layer micro-mirror array in epitaxial lateral overgrowth gallium nitride.

PubMed

Huang, Chen-Yang; Ku, Hao-Min; Liao, Wei-Tsai; Chao, Chu-Li; Tsay, Jenq-Dar; Chao, Shiuh

2009-03-30

Ta2O5 / SiO2 dielectric multi-layer micro-mirror array (MMA) with 3mm mirror size and 6mm array period was fabricated on c-plane sapphire substrate. The MMA was subjected to 1200 degrees C high temperature annealing and remained intact with high reflectance in contrast to the continuous multi-layer for which the layers have undergone severe damage by 1200 degrees C annealing. Epitaxial lateral overgrowth (ELO) of gallium nitride (GaN) was applied to the MMA that was deposited on both sapphire and sapphire with 2:56 mm GaN template. The MMA was fully embedded in the ELO GaN and remained intact. The result implies that our MMA is compatible to the high temperature growth environment of GaN and the MMA could be incorporated into the structure of the micro-LED array as a one to one micro backlight reflector, or as the patterned structure on the large area LED for controlling the output light.

Material optimization of multi-layered enhanced nanostructures

NASA Astrophysics Data System (ADS)

Strobbia, Pietro

The employment of surface enhanced Raman scattering (SERS)-based sensing in real-world scenarios will offer numerous advantages over current optical sensors. Examples of these advantages are the intrinsic and simultaneous detection of multiple analytes, among many others. To achieve such a goal, SERS substrates with throughput and reproducibility comparable to commonly used fluorescence sensors have to be developed. To this end, our lab has discovered a multi-layer geometry, based on alternating films of a metal and a dielectric, that amplifies the SERS signal (multi-layer enhancement). The advantage of these multi-layered structures is to amplify the SERS signal exploiting layer-to-layer interactions in the volume of the structures, rather than on its surface. This strategy permits an amplification of the signal without modifying the surface characteristics of a substrate, and therefore conserving its reproducibility. Multi-layered structures can therefore be used to amplify the sensitivity and throughput of potentially any previously developed SERS sensor. In this thesis, these multi-layered structures were optimized and applied to different SERS substrates. The role of the dielectric spacer layer in the multi-layer enhancement was elucidated by fabricating spacers with different characteristics and studying their effect on the overall enhancement. Thickness, surface coverage and physical properties of the spacer were studied. Additionally, the multi-layered structures were applied to commercial SERS substrates and to isolated SERS probes. Studies on the dependence of the multi-layer enhancement on the thickness of the spacer demonstrated that the enhancement increases as a function of surface coverage at sub-monolayer thicknesses, due to the increasing multi-layer nature of the substrates. For fully coalescent spacers the enhancement decreases as a function of thickness, due to the loss of interaction between proximal metallic films. The influence of the physical properties of the spacer on the multi-layer enhancement were also studied. The trends in Schottky barrier height, interfacial potential and dielectric constant were isolated by using different materials as spacers (i.e., TiO2, HfO2, Ag 2O and Al2O3). The results show that the bulk dielectric constant of the material can be used to predict the relative magnitude of the multi-layer enhancement, with low dielectric constant materials performing more efficiently as spacers. Optimal spacer layers were found to be ultrathin coalescent films (ideally a monolayer) of low dielectric constant materials. Finally, multi-layered structures were observed to be employable to amplify SERS in drastically different substrate geometries. The multi-layered structures were applied to disposable commercial SERS substrates (i.e., Klarite). This project involved the regeneration of the used substrates, by stripping and redepositing the gold coating layer, and their amplification, by using the multi-layer geometry. The latter was observed to amplify the sensitivity of the substrates. Additionally, the multi-layered structures were applied to probes dispersed in solution. Such probes were observed to yield stronger SERS signal when optically trapped and to reduce the background signal. The application of the multi-layered structures on trapped probes, not only further amplified the SERS signal, but also increased the maximum number of applicable layers for the structures.

Investigation of a broadband coherent perfect absorber in a multi-layer structure by using the transfer matrix method

NASA Astrophysics Data System (ADS)

Na, Jihoon; Noh, Heeso

2018-01-01

We investigated a multi-layer structure for a broadband coherent perfect absorber (CPA). The transfer matrix method (TMM) is useful for analyzing the optical properties of structures and optimizing multi-layer structures. The broadband CPA strongly depends on the phase of the light traveling in one direction and the light reflected within the structure. The TMM simulation shows that the absorption bandwidth is increased by 95% in a multi-layer CPA compared to that in a single-layer CPA.

Multi-layered nanocomposite dielectrics for high density organic memory devices

NASA Astrophysics Data System (ADS)

Kang, Moonyeong; Chung, Kyungwha; Baeg, Kang-Jun; Kim, Dong Ha; Kim, Choongik

2015-01-01

We fabricated organic memory devices with metal-pentacene-insulator-silicon structure which contain double dielectric layers comprising 3D pattern of Au nanoparticles (Au NPs) and block copolymer (PS-b-P2VP). The role of Au NPs is to charge/discharge carriers upon applied voltage, while block copolymer helps to form highly ordered Au NP patterns in the dielectric layer. Double-layered nanocomposite dielectrics enhanced the charge trap density (i.e., trapped charge per unit area) by Au NPs, resulting in increase of the memory window (ΔVth).

Detection of Quinoline in G. boninense-Infected Plants Using Functionalized Multi-Walled Carbon Nanotubes: A Field Study.

PubMed

Akanbi, Fowotade Sulayman; Yusof, Nor Azah; Abdullah, Jaafar; Sulaiman, Yusran; Hushiarian, Roozbeh

2017-07-01

Carbon nanotubes (CNTs) reinforced with gold nanoparticles (AuNPs) and chitosan nanoparticles (CTSNPs) were anchored on a screen-printed electrode to fabricate a multi-walled structure for the detection of quinoline. The surface morphology of the nanocomposites and the modified electrode was examined by an ultra-high resolution field emission scanning electron microscope (FESEM), and Fourier-transform infrared (FT-IR) spectroscopy was used to confirm the presence of specific functional groups on the multi-walled carbon nanotubes MWCNTs. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were used to monitor the layer-by-layer assembly of ultra-thin films of nanocomposites on the surface of the electrode and other electrochemical characterizations. Under optimized conditions, the novel sensor displayed outstanding electrochemical reactivity towards the electro-oxidation of quinoline. The linear range was fixed between 0.0004 and 1.0 μM, with a limit of detection (LOD) of 3.75 nM. The fabricated electrode exhibited high stability with excellent sensitivity and selectivity, specifically attributable to the salient characteristics of AuNPs, CTSNPs, and MWCNTs and the synergistic inter-relationship between them. The newly developed electrode was tested in the field. The Ipa increased with an increase in the amount of quinoline solution added, and the peak potential deviated minimally, depicting the real capability of the newly fabricated electrode.

Detection of Quinoline in G. boninense-Infected Plants Using Functionalized Multi-Walled Carbon Nanotubes: A Field Study

PubMed Central

Akanbi, Fowotade Sulayman; Yusof, Nor Azah; Abdullah, Jaafar; Sulaiman, Yusran; Hushiarian, Roozbeh

2017-01-01

Carbon nanotubes (CNTs) reinforced with gold nanoparticles (AuNPs) and chitosan nanoparticles (CTSNPs) were anchored on a screen-printed electrode to fabricate a multi-walled structure for the detection of quinoline. The surface morphology of the nanocomposites and the modified electrode was examined by an ultra-high resolution field emission scanning electron microscope (FESEM), and Fourier-transform infrared (FT-IR) spectroscopy was used to confirm the presence of specific functional groups on the multi-walled carbon nanotubes MWCNTs. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were used to monitor the layer-by-layer assembly of ultra-thin films of nanocomposites on the surface of the electrode and other electrochemical characterizations. Under optimized conditions, the novel sensor displayed outstanding electrochemical reactivity towards the electro-oxidation of quinoline. The linear range was fixed between 0.0004 and 1.0 μM, with a limit of detection (LOD) of 3.75 nM. The fabricated electrode exhibited high stability with excellent sensitivity and selectivity, specifically attributable to the salient characteristics of AuNPs, CTSNPs, and MWCNTs and the synergistic inter-relationship between them. The newly developed electrode was tested in the field. The Ipa increased with an increase in the amount of quinoline solution added, and the peak potential deviated minimally, depicting the real capability of the newly fabricated electrode. PMID:28671561

Process for Fabrication of Superconducting Vias for Electrical Connection to Groundplane in Cryogenic Detectors

NASA Technical Reports Server (NTRS)

Denis, Kevin L. (Inventor)

2018-01-01

Disclosed are systems, methods, and non-transitory computer-readable storage media for fabrication of silicon on insulator (SOI) wafers with a superconductive via for electrical connection to a groundplane. Fabrication of the SOI wafer with a superconductive via can involve depositing a superconducting groundplane onto a substrate with the superconducting groundplane having an oxidizing layer and a non-oxidizing layer. A layer of monocrystalline silicon can be bonded to the superconducting groundplane and a photoresist layer can be applied to the layer of monocrystalline silicon and the SOI wafer can be etched with the oxygen rich etching plasma, resulting in a monocrystalline silicon top layer with a via that exposes the superconducting groundplane. Then, the fabrication can involve depositing a superconducting surface layer to cover the via.

Very high S-band microwave absorption of carbon nanotube buckypapers with Mn nanoparticle interlayers

NASA Astrophysics Data System (ADS)

Lu, Shaowei; Bai, Yaoyao; Wang, Jijie; Zhang, Lu; Tian, Caijiao; Ma, Keming; Wang, Xiaoqiang

2018-03-01

Flexible and high-performance electromagnetic absorbing materials of multi-walled carbon nanotube (MWCNT) buckypapers with Mn nanoparticles (NPSs) interlayer were fabricated via monodisperse solutions through layer by layer vacuum filtration method. The morphology and element composition of buckypapers were characterized by scanning electron microscopy, energy dispersive spectrometer, and X-ray diffraction. The formation of flexible MWCNT buckypapers with Mn NPS (0-30 wt. %) interlayer was attributed to nanostructure and morphology of the samples. When the blended Mn NPS content in buckypapers is 20 wt. %, there are evidently two larger absorption peaks (-13.2 dB at 3.41 GHz, -15.6 dB at 3.52 GHz) of the buckypaper with an absorbing thickness of 0.1 mm. The fundamental microwave absorption mechanism of the buckypapers is discussed. This work opens a new pathway towards tuning microwave absorbers performance and this method can be extended to exploit other excellent microwave absorbers with interlayer.

Abrasion Testing of Candidate Outer Layer Fabrics for Lunar EVA Space Suits

NASA Technical Reports Server (NTRS)

Mitchell, Kathryn

2009-01-01

During the Apollo program, the space suit outer layer fabrics were severely abraded after just a few Extravehicular Activities (EVAs). For example, the Apollo 12 commander reported abrasive wear on the boots, which penetrated the outer layer fabric into the thermal protection layers after less than eight hours of surface operations. Current plans for the Constellation Space Suit Element require the space suits to support hundreds of hours of EVA on the Lunar surface, creating a challenge for space suit designers to utilize materials advances made over the last forty years and improve upon the space suit fabrics used in the Apollo program. A test methodology has been developed by the NASA Johnson Space Center Crew and Thermal Systems Division for establishing comparative abrasion wear characteristics between various candidate space suit outer layer fabrics. The abrasion test method incorporates a large rotary drum tumbler with rocks and loose lunar simulant material to induce abrasion in fabric test cylinder elements, representative of what might occur during long term planetary surface EVAs. Preliminary materials screening activities were conducted to determine the degree of wear on representative space suit outer layer materials and the corresponding dust permeation encountered between subsequent sub-layers of thermal protective materials when exposed to a simulated worst case eight hour EVA. The test method was used to provide a preliminary evaluation of four candidate outer layer fabrics for future planetary surface space suit applications. This paper provides a review of previous abrasion studies on space suit fabrics, details the methodologies used for abrasion testing in this particular study, shares the results of the testing, and provides recommendations for future work.

Abrasion Testing of Candidate Outer Layer Fabrics for Lunar EVA Space Suits

NASA Technical Reports Server (NTRS)

Mitchell, Kathryn C.

2010-01-01

During the Apollo program, the space suit outer layer fabrics were badly abraded after just a few Extravehicular Activities (EVAs). For example, the Apollo 12 commander reported abrasive wear on the boots, which penetrated the outer layer fabric into the thermal protection layers after less than eight hours of surface operations. Current plans for the Constellation Space Suit Element require the space suits to support hundreds of hours of EVA on the Lunar surface, creating a challenge for space suit designers to utilize materials advances made over the last forty years and improve upon the space suit fabrics used in the Apollo program. A test methodology has been developed by the NASA Johnson Space Center Crew and Thermal Systems Division for establishing comparative abrasion wear characteristics between various candidate space suit outer layer fabrics. The abrasion test method incorporates a large rotary drum tumbler with rocks and loose lunar simulant material to induce abrasion in fabric test cylinder elements, representative of what might occur during long term planetary surface EVAs. Preliminary materials screening activities were conducted to determine the degree of wear on representative space suit outer layer materials and the corresponding dust permeation encountered between subsequent sub -layers of thermal protective materials when exposed to a simulated worst case eight hour EVA. The test method was used to provide a preliminary evaluation of four candidate outer layer fabrics for future planetary surface space suit applications. This Paper provides a review of previous abrasion studies on space suit fabrics, details the methodologies used for abrasion testing in this particular study, and shares the results and conclusions of the testing.

All-Aluminum Thin Film Transistor Fabrication at Room Temperature

PubMed Central

Yao, Rihui; Zheng, Zeke; Zeng, Yong; Liu, Xianzhe; Ning, Honglong; Hu, Shiben; Tao, Ruiqiang; Chen, Jianqiu; Cai, Wei; Xu, Miao; Wang, Lei; Lan, Linfeng; Peng, Junbiao

2017-01-01

Bottom-gate all-aluminum thin film transistors with multi conductor/insulator nanometer heterojunction were investigated in this article. Alumina (Al2O3) insulating layer was deposited on the surface of aluminum doping zinc oxide (AZO) conductive layer, as one AZO/Al2O3 heterojunction unit. The measurements of transmittance electronic microscopy (TEM) and X-ray reflectivity (XRR) revealed the smooth interfaces between ~2.2-nm-thick Al2O3 layers and ~2.7-nm-thick AZO layers. The devices were entirely composited by aluminiferous materials, that is, their gate and source/drain electrodes were respectively fabricated by aluminum neodymium alloy (Al:Nd) and pure Al, with Al2O3/AZO multilayered channel and AlOx:Nd gate dielectric layer. As a result, the all-aluminum TFT with two Al2O3/AZO heterojunction units exhibited a mobility of 2.47 cm2/V·s and an Ion/Ioff ratio of 106. All processes were carried out at room temperature, which created new possibilities for green displays industry by allowing for the devices fabricated on plastic-like substrates or papers, mainly using no toxic/rare materials. PMID:28772579

Fabrication technology of CNT-Nickel Oxide based planar pseudocapacitor for MEMS and NEMS

NASA Astrophysics Data System (ADS)

Lebedev, E. A.; Kitsyuk, E. P.; Gavrilin, I. M.; Gromov, D. G.; Gruzdev, N. E.; Gavrilov, S. A.; Dronov, A. A.; Pavlov, A. A.

2015-11-01

Fabrication technology of planar pseudocapacitor (PsC) based on carbon nanotube (CNT) forest, synthesized using plasma enhanced chemical vapor deposition (PECVD) method, covered with thin nickel oxide layer deposited by successive ionic layer adsorption and reaction (SILAR) method, is demonstrated. Dependences of deposited oxide layers thickness on device specific capacities is studied. It is shown that pseudocapacity of nickel oxide thin layer increases specific capacity of the CNT's based device up to 2.5 times.

Optomechanical Coatings for High-Power Mirrors and Adaptive Optics

DTIC Science & Technology

2009-03-24

micromirror under illumination is to increase the reflectance of the mirror. A multi-layer dielectric mirror becomes a necessity at moderate to high energies...structure. This technique was successfully demonstrated on a micromirror array fabricated by Sandia National Laboratory. Fig. 2-(1) shows the curvature of...a micromirror roughly 500 1-1m in diameter under varying laser illumination, with and without a 3-pair DBR mirror designed and fabricated by our

Preparation of Flame Retardant Polyacrylonitrile Fabric Based on Sol-Gel and Layer-by-Layer Assembly

PubMed Central

Ren, Yuanlin; Huo, Tongguo; Qin, Yiwen; Liu, Xiaohui

2018-01-01

This paper aims to develop a novel method, i.e., sol-gel combined with layer-by-layer assembly technology, to impart flame retardancy on polyacrylonitrile (PAN) fabrics. Silica-sol was synthesized via the sol-gel process and acted as cationic solution, and phytic acid (PA) was used as the anionic medium. Flame-retardant-treated PAN fabric (FR-PAN) could achieve excellent flame retardancy with 10 bilayer (10BL) coating through layer-by-layer assembly. The structure of the fabrics was characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The thermal stability and flame retardancy were evaluated by thermogravimetric (TG) analysis, cone calorimetry (CC) and limiting oxygen index (LOI). The LOI value of the coated fabric was up to 33.2 vol % and the char residue at 800 °C also increased to 57 wt %. Cone calorimetry tests revealed that, compared to the control fabric, the peak of heat release rate (PHRR) and total heat release (THR) of FR-PAN decreased by 66% and 73%, respectively. These results indicated that sol-gel combined with layer-by-layer assembly technique could impart PAN fabric with satisfactory flame-retardant properties, showing an efficient flame retardant strategy for PAN fabric. PMID:29570646

Preparation of Flame Retardant Polyacrylonitrile Fabric Based on Sol-Gel and Layer-by-Layer Assembly.

PubMed

Ren, Yuanlin; Huo, Tongguo; Qin, Yiwen; Liu, Xiaohui

2018-03-23

This paper aims to develop a novel method, i.e., sol-gel combined with layer-by-layer assembly technology, to impart flame retardancy on polyacrylonitrile (PAN) fabrics. Silica-sol was synthesized via the sol-gel process and acted as cationic solution, and phytic acid (PA) was used as the anionic medium. Flame-retardant-treated PAN fabric (FR-PAN) could achieve excellent flame retardancy with 10 bilayer (10BL) coating through layer-by-layer assembly. The structure of the fabrics was characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The thermal stability and flame retardancy were evaluated by thermogravimetric (TG) analysis, cone calorimetry (CC) and limiting oxygen index (LOI). The LOI value of the coated fabric was up to 33.2 vol % and the char residue at 800 °C also increased to 57 wt %. Cone calorimetry tests revealed that, compared to the control fabric, the peak of heat release rate (PHRR) and total heat release (THR) of FR-PAN decreased by 66% and 73%, respectively. These results indicated that sol-gel combined with layer-by-layer assembly technique could impart PAN fabric with satisfactory flame-retardant properties, showing an efficient flame retardant strategy for PAN fabric.

Investigation of Implantable Multi-Channel Electrode Array in Rat Cerebral Cortex Used for Recording

NASA Astrophysics Data System (ADS)

Taniguchi, Noriyuki; Fukayama, Osamu; Suzuki, Takafumi; Mabuchi, Kunihiko

There have recently been many studies concerning the control of robot movements using neural signals recorded from the brain (usually called the Brain-Machine interface (BMI)). We fabricated implantable multi-electrode arrays to obtain neural signals from the rat cerebral cortex. As any multi-electrode array should have electrode alignment that minimizes invasion, it is necessary to customize the recording site. We designed three types of 22-channel multi-electrode arrays, i.e., 1) wide, 2) three-layered, and 3) separate. The first extensively covers the cerebral cortex. The second has a length of 2 mm, which can cover the area of the primary motor cortex. The third array has a separate structure, which corresponds to the position of the forelimb and hindlimb areas of the primary motor cortex. These arrays were implanted into the cerebral cortex of a rat. We estimated the walking speed from neural signals using our fabricated three-layered array to investigate its feasibility for BMI research. The neural signal of the rat and its walking speed were simultaneously recorded. The results revealed that evaluation using either the anterior electrode group or posterior group provided accurate estimates. However, two electrode groups around the center yielded poor estimates although it was possible to record neural signals.

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

Black phosphorus quantum dots for femtosecond laser photonics

NASA Astrophysics Data System (ADS)

Liu, Meng; Jiang, Xiao-Fang; Yan, Yu-Rong; Wang, Xu-De; Luo, Ai-Ping; Xu, Wen-Cheng; Luo, Zhi-Chao

2018-01-01

As a rising two-dimensional (2D) nanomaterial, layered black phosphorus (BP) nanosheets have shown promising applications in electronics and photonics. Besides the 2D layered structure, recently black phosphorus quantum dots (BPQDs) exhibiting unique optoelectronic properties had been successfully fabricated. However, the nonlinear optical properties of BPQDs at the telecommunication band have not been investigated. Herein, we synthesized the BPQDs by using a liquid exfoliation method that combined probe sonication and bath sonication. It was found that the evident saturable absorption ability of BPQDs at 1.55 μm waveband could be clearly observed. As for the applications of ultrafast photonics, we fabricated the BPQDs saturable absorber (BPQDs-SA) and applied it to an ultrafast laser. By virtue of the excellent nonlinear optical properties of BPQDs, the fiber laser delivers the stable pulse train with duration as short as 291 fs, whose performance could, to the best of our knowledge, compete with nowadays' commercial optical saturable absorber devices. In addition, due to the highly nonlinear optical effect generated by the fabricated BPQDs-SA, the multi-soliton nonlinear dynamics in the fiber laser were also investigated. The obtained results suggest that the BPQDs could be an attractive nonlinear optical material for applications in the field of nonlinear optics.

Planarization of metal films for multilevel interconnects by pulsed laser heating

DOEpatents

Tuckerman, David B.

1987-01-01

In the fabrication of multilevel integrated circuits, each metal layer is planarized by heating to momentarily melt the layer. The layer is melted by sweeping laser pulses of suitable width, typically about 1 microsecond duration, over the layer in small increments. The planarization of each metal layer eliminates irregular and discontinuous conditions between successive layers. The planarization method is particularly applicable to circuits having ground or power planes and allows for multilevel interconnects. Dielectric layers can also be planarized to produce a fully planar multilevel interconnect structure. The method is useful for the fabrication of VLSI circuits, particularly for wafer-scale integration.

Fabrication and Cytocompatibility of In Situ Crosslinked Carbon Nanomaterial Films

PubMed Central

Patel, Sunny C.; Lalwani, Gaurav; Grover, Kartikey; Qin, Yi-Xian; Sitharaman, Balaji

2015-01-01

Assembly of carbon nanomaterials into two-dimensional (2D) coatings and films that harness their unique physiochemical properties may lead to high impact energy capture/storage, sensors, and biomedical applications. For potential biomedical applications, the suitability of current techniques such as chemical vapor deposition, spray and dip coating, and vacuum filtration, employed to fabricate macroscopic 2D all carbon coatings or films still requires thorough examination. Each of these methods presents challenges with regards to scalability, suitability for a large variety of substrates, mechanical stability of coatings or films, or biocompatibility. Herein we report a coating process that allow for rapid, in situ chemical crosslinking of multi-walled carbon nanotubes (MWCNTs) into macroscopic all carbon coatings. The resultant coatings were found to be continuous, electrically conductive, significantly more robust, and cytocompatible to human adipose derived stem cells. The results lay groundwork for 3D layer-on-layer nanomaterial assemblies (including various forms of graphene) and also opens avenues to further explore the potential of MWCNT films as a novel class of nano-fibrous mats for tissue engineering and regenerative medicine. PMID:26018775

Influence of the Geometric Parameters on the Mechanical Behaviour of Fabric Reinforced Composite Laminates

NASA Astrophysics Data System (ADS)

Axinte, Andrei; Taranu, Nicolae; Bejan, Liliana

2016-10-01

A polymer fabric reinforced composite is a high performance material, which combines strength of the fibres with the flexibility and ductility of the matrix. For a better drapeability, the tows of fibres are interleaved, resulting the woven fabric, used as reinforcement. The complex geometric shape of the fabric is of paramount importance in establishing the deformability of the textile reinforced composite laminates. In this paper, an approach based on Classical Lamination Theory ( CLT), combined with Finite Element Methods ( FEM), using Failure Analysis and Internal Load Redistribution, is utilised, in order to compare the behaviour of the material under specific loads. The main goal is to analyse the deformability of certain types of textile reinforced composite laminates, using carbon fibre satin as reinforcement and epoxy resin as matrix. This is accomplished by studying the variation of the in-plane strains, given the fluctuation of several geometric parameters, namely the width of the reinforcing tow, the gap between two consecutive tows, the angle of laminae in a multi-layered configuration and the tows fibre volume fraction.

Conformally encapsulated multi-electrode arrays with seamless insulation

DOEpatents

Tabada, Phillipe J.; Shah, Kedar G.; Tolosa, Vanessa; Pannu, Satinderall S.; Tooker, Angela; Delima, Terri; Sheth, Heeral; Felix, Sarah

2016-11-22

Thin-film multi-electrode arrays (MEA) having one or more electrically conductive beams conformally encapsulated in a seamless block of electrically insulating material, and methods of fabricating such MEAs using reproducible, microfabrication processes. One or more electrically conductive traces are formed on scaffold material that is subsequently removed to suspend the traces over a substrate by support portions of the trace beam in contact with the substrate. By encapsulating the suspended traces, either individually or together, with a single continuous layer of an electrically insulating material, a seamless block of electrically insulating material is formed that conforms to the shape of the trace beam structure, including any trace backings which provide suspension support. Electrical contacts, electrodes, or leads of the traces are exposed from the encapsulated trace beam structure by removing the substrate.

Low Voltage Electrowetting-on-Dielectric Platform using Multi-Layer Insulators

PubMed Central

Lin, Yan-You; Evans, Randall D.; Welch, Erin; Hsu, Bang-Ning; Madison, Andrew C.; Fair, Richard B.

2010-01-01

A low voltage, two-level-metal, and multi-layer insulator electrowetting-on-dielectric (EWD) platform is presented. Dispensing 300pl droplets from 140nl closed on-chip reservoirs was accomplished with as little as 11.4V solely through EWD forces, and the actuation threshold voltage was 7.2V with a 1Hz voltage switching rate between electrodes. EWD devices were fabricated with a multilayer insulator consisting of 135nm sputtered tantalum pentoxide (Ta2O5) and 180nm parylene C coated with 70nm of CYTOP. Furthermore, the minimum actuation threshold voltage followed a previously published scaling model for the threshold voltage, VT, which is proportional to (t/εr)1/2, where t and εr are the insulator thickness and dielectric constant respectively. Device threshold voltages are compared for several insulator thicknesses (200nm, 500nm, and 1µm), different dielectric materials (parylene C and tantalum pentoxide), and homogeneous versus heterogeneous compositions. Additionally, we used a two-level-metal fabrication process, which enables the fabrication of smaller and denser electrodes with high interconnect routing flexibility. We also have achieved low dispensing and actuation voltages for scaled devices with 30pl droplets. PMID:20953362

Direct growth of graphene-dielectric bi-layer structure on device substrates from Si-based polymer

NASA Astrophysics Data System (ADS)

Seo, Hong-Kyu; Kim, Kyunghun; Min, Sung-Yong; Lee, Yeongjun; Eon Park, Chan; Raj, Rishi; Lee, Tae-Woo

2017-06-01

To facilitate the utilization of graphene films in conventional semiconducting devices (e.g. transistors and memories) which includes an insulating layer such as gate dielectric, facile synthesis of bi-layers composed of a graphene film and an insulating layer by one-step thermal conversion will be very important. We demonstrate a simple, inexpensive, scalable and patternable process to synthesize graphene-dielectric bi-layer films from solution-processed polydimethylsiloxane (PDMS) under a Ni capping layer. This method fabricates graphene-dielectric bi-layer structure simultaneously directly on substrate by thermal conversion of PDMS without using additional graphene transfer and patterning process or formation of an expensive dielectric layer, which makes the device fabrication process much easier. The graphene-dielectric bi-layer on a conducting substrate was used in bottom-contact pentacene field-effect transistors that showed ohmic contact and small hysteresis. Our new method will provide a way to fabricate flexible electronic devices simply and inexpensively.

A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme

PubMed Central

Alqasaimeh, Muawia Salameh; Heng, Lee Yook; Ahmad, Musa

2007-01-01

An optical urea biosensor was fabricated by stacking several layers of sol-gel films. The stacking of the sol-gel films allowed the immobilization of a Nile Blue chromoionophore (ETH 5294) and urease enzyme separately without the need of any chemical attachment procedure. The absorbance response of the biosensor was monitored at 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel film format enabled higher enzyme loading in the biosensor to be achieved. The urea optical biosensor constructed from three layers of sol-gel films that contained urease demonstrated a much wider linear response range of up to 100 mM urea when compared with biosensors that constructed from 1-2 layers of films. Analysis of urea in urine samples with this optical urea biosensor yielded results similar to that determined by a spectrophotometric method using the reagent p-dimethylaminobenzaldehyde (R2 = 0.982, n = 6). The average recovery of urea from urine samples using this urea biosensor is approximately 103%.

Highly Reflective Multi-stable Electrofluidic Display Pixels

NASA Astrophysics Data System (ADS)

Yang, Shu

Electronic papers (E-papers) refer to the displays that mimic the appearance of printed papers, but still owning the features of conventional electronic displays, such as the abilities of browsing websites and playing videos. The motivation of creating paper-like displays is inspired by the truths that reading on a paper caused least eye fatigue due to the paper's reflective and light diffusive nature, and, unlike the existing commercial displays, there is no cost of any form of energy for sustaining the displayed image. To achieve the equivalent visual effect of a paper print, an ideal E-paper has to be a highly reflective with good contrast ratio and full-color capability. To sustain the image with zero power consumption, the display pixels need to be bistable, which means the "on" and "off" states are both lowest energy states. Pixel can change its state only when sufficient external energy is given. There are many emerging technologies competing to demonstrate the first ideal E-paper device. However, none is able to achieve satisfactory visual effect, bistability and video speed at the same time. Challenges come from either the inherent physical/chemical properties or the fabrication process. Electrofluidic display is one of the most promising E-paper technologies. It has successfully demonstrated high reflectivity, brilliant color and video speed operation by moving colored pigment dispersion between visible and invisible places with electrowetting force. However, the pixel design did not allow the image bistability. Presented in this dissertation are the multi-stable electrofluidic display pixels that are able to sustain grayscale levels without any power consumption, while keeping the favorable features of the previous generation electrofluidic display. The pixel design, fabrication method using multiple layer dry film photoresist lamination, and physical/optical characterizations are discussed in details. Based on the pixel structure, the preliminary results of a simplified design and fabrication method are demonstrated. As advanced research topics regarding the device optical performance, firstly an optical model for evaluating reflective displays' light out-coupling efficiency is established to guide the pixel design; Furthermore, Aluminum surface diffusers are analytically modeled and then fabricated onto multi-stable electrofluidic display pixels to demonstrate truly "white" multi-stable electrofluidic display modules. The achieved results successfully promoted multi-stable electrofluidic display as excellent candidate for the ultimate E-paper device especially for larger scale signage applications.

Method of fabricating germanium and gallium arsenide devices

NASA Technical Reports Server (NTRS)

Jhabvala, Murzban (Inventor)

1990-01-01

A method of semiconductor diode fabrication is disclosed which relies on the epitaxial growth of a precisely doped thickness layer of gallium arsenide or germanium on a semi-insulating or intrinsic substrate, respectively, of gallium arsenide or germanium by either molecular beam epitaxy (MBE) or by metal-organic chemical vapor deposition (MOCVD). The method involves: depositing a layer of doped or undoped silicon dioxide on a germanium or gallium arsenide wafer or substrate, selectively removing the silicon dioxide layer to define one or more surface regions for a device to be fabricated thereon, growing a matched epitaxial layer of doped germanium or gallium arsenide of an appropriate thickness using MBE or MOCVD techniques on both the silicon dioxide layer and the defined one or more regions; and etching the silicon dioxide and the epitaxial material on top of the silicon dioxide to leave a matched epitaxial layer of germanium or gallium arsenide on the germanium or gallium arsenide substrate, respectively, and upon which a field effect device can thereafter be formed.

Microfluidic channel-based wireless charging and communication platform for microsensors with miniaturized onboard antenna

NASA Astrophysics Data System (ADS)

Duan, G.; Zhao, X.; Seren, H. R.; Chen, C.; Li, A.; Zhang, X.

2016-12-01

A double layer spiral antenna with side length of 380 μm was fabricated by a multi-step electroplating process, and integrated with a commercialized passive RFID chip to realize the RF power harvesting and communication functions of a microsensor. To power up and communicate with the microchips, a single layer spiral reader antenna was fabricated on top of a glass substrate with side length of 1 mm. The microchips and the reader antenna were both optimized at the frequency of 915 MHz. Due to the small size of the reader antenna, the strength of the magnetic field decreased dramatically along the axial direction of the reader antenna, which limited the working distance to within 1 mm. To enclose the microchips within the reading range, a three-layer microfluidic channel was designed and fabricated. The channel and cover layers were fabricated by laser cutting of acrylic sheets, and bonded with the glass substrate to form the channel. To operate multiple microchips simultaneously, separation and focusing function units were also designed. Low loss pump oil was used to transport the microchips flowing inside the channel. Within the reading area, the microchips were powered up, and their ID information was retrieved and displayed on the computer interface successfully.

Modeling of stress-induced curvature in surface-micromachined devices

NASA Astrophysics Data System (ADS)

Cowan, William D.; Bright, Victor M.; Elvin, Alex A.; Koester, David A.

1997-09-01

This paper compares measured to modeled stress-induced curvature of simple piston micromirrors. Two similar flexure-beam micromirror designs were fabricate using the 11th DARPA-supported multi-user MEMS processes (MUMPs) run. The test devices vary only in the MUMPs layers used for fabrication. In one case the mirror plate is the 1.5 micrometers thick Poly2 layer. The other mirror design employs stacked Poly1 and Poly2 layers for a total thickness of 3.5 micrometers . Both mirror structures are covered with the standard MUMPs metallization of approximately 200 angstrom of chromium and 0.5 micrometers of gold. Curvature of these devices was measured to within +/- 5 nm with a computer controlled microscope laser interferometer system. As intended, the increased thickness of the stacked polysilicon layers reduces the mirror curvature by a factor of 4. The two micromirror designs were modeled using IntelliCAD, a commercial CAD system for MEMS. The basis of analysis was the finite element method. Simulated results using MUMPs 11 film parameters showed qualitative agreement with measured data, but obvious quantitative differences. Subsequent remeasurement of the metal stress and use of the new value significantly improved model agreement with the measured data. The paper explores the effect of several film parameters on the modeled structures. Implications for MEMS film metrology, and test structures are considered.

The cell engineering construction and function evaluation of multi-layer biochip dialyzer.

PubMed

Zhu, Wen; Li, Jiwei; Liu, Jianfeng

2013-10-01

We report the fabrication and function evaluation of multi-layer biochip dialyzer. Such device may potentially be applied to the wearable hemodialysis systems. By merging the advantages of microfluidic chip technology with cell engineering, both functions of glomerular filtration and renal tubule physiological activity are integrated in the same device. This device is designed into a laminated structure, in which the chip number of the superimposed layer can be arbitrarily tailored in accordance with the requirements of dialysis capacity. We propose that such structure can overcome the obstacles of large size and detached structure of the traditional hollow fiber dialyzer. To construct this multilayer biochips dialyzer, two types of dialyzer device with two-layered and six-layered chips are assembled, respectively. Cell adhesion and proliferation on three different dialysis membrane materials under static and dynamic conditions are investigated and compared. The filtration capability, re-absorption function and excrete ammonia function of the resulting multi-layer biochip dialyzer are evaluated. The results reveal that the constructed device can perform higher filtration efficiency and also play a role of renal tubule. This methodology may be useful in developing "scaling down" artificial kidneys that can act as wearable or even implantable hemodialysis systems.

Charge and spin transport in metal-graphene-metal vertical junctions

NASA Astrophysics Data System (ADS)

Cobas, Enrique; van't Erve, Olaf; Cheng, Shu-Fan; Culbertson, James; Jernigan, Glenn; Bussman, Konrad; Jonker, Berry

We observe negative magnetoresistance(MR) in metallic NiFe(111)|multi-layer graphene|Fe heterostructures consistent with minority spin filtering. The MR is -5 percent at room temperature and -12 percent at 10 K. The transport properties and temperature dependence are metallic. We further investigate the out-of-plane (c-axis) resistivity and magnetoresistance of multi-layer graphene between metal surfaces. We fabricate various metal-graphene-metal vertical heterostructures via chemical vapor deposition directly on lattice-matched crystalline metal films including NiFe(111) and Co(0002) and in-situ electron beam evaporation of NiFe, Co, Ni, Fe, Cu and Au.

Schottky solar cell using few-layered transition metal dichalcogenides toward large-scale fabrication of semitransparent and flexible power generator.

PubMed

Akama, Toshiki; Okita, Wakana; Nagai, Reito; Li, Chao; Kaneko, Toshiro; Kato, Toshiaki

2017-09-20

Few-layered transition metal dichalcogenides (TMDs) are known as true two-dimensional materials, with excellent semiconducting properties and strong light-matter interaction. Thus, TMDs are attractive materials for semitransparent and flexible solar cells for use in various applications. Hoewver, despite the recent progress, the development of a scalable method to fabricate semitransparent and flexible solar cells with mono- or few-layered TMDs remains a crucial challenge. Here, we show easy and scalable fabrication of a few-layered TMD solar cell using a Schottky-type configuration to obtain a power conversion efficiency (PCE) of approximately 0.7%, which is the highest value reported with few-layered TMDs. Clear power generation was also observed for a device fabricated on a large SiO 2 and flexible substrate, demonstrating that our method has high potential for scalable production. In addition, systematic investigation revealed that the PCE and external quantum efficiency (EQE) strongly depended on the type of photogenerated excitons (A, B, and C) because of different carrier dynamics. Because high solar cell performance along with excellent scalability can be achieved through the proposed process, our fabrication method will contribute to accelerating the industrial use of TMDs as semitransparent and flexible solar cells.

High-reflective colorful films fabricated by all-solid multi-layer cholesteric structures

NASA Astrophysics Data System (ADS)

Li, Y.; Luo, D.

2018-02-01

We demonstrate all-solid-state film with high-reflectivity based on cholesteric template. The adhesive (NOA81) is both filler and an adhesive, which can be avoids interfacial losses. The reflected right- and left-circularly polarized light has been developed by roll-to-roll method, and the reflectance of the films is more than 78%. Here, the all-solid film was used in distribute feedback laser with dye-doped. In addition, this films also used in include flexible reflective display, color pixels in digital photographs, printing and colored cladding of variety of objects.

Preparation of multi-layer film consisting of hydrogen-free DLC and nitrogen-containing DLC for conductive hard coating

NASA Astrophysics Data System (ADS)

Iijima, Yushi; Harigai, Toru; Isono, Ryo; Degai, Satoshi; Tanimoto, Tsuyoshi; Suda, Yoshiyuki; Takikawa, Hirofumi; Yasui, Haruyuki; Kaneko, Satoru; Kunitsugu, Shinsuke; Kamiya, Masao; Taki, Makoto

2018-01-01

Conductive hard-coating films have potential application as protective films for contact pins used in the electrical inspection process for integrated circuit chips. In this study, multi-layer diamond-like carbon (DLC) films were prepared as conductive hard-coating films. The multi-layer DLC films consisting of DLC and nitrogen-containing DLC (N-DLC) film were prepared using a T-shape filtered arc deposition method. Periodic DLC/N-DLC four-layer and eight-layer films had the same film thickness by changing the thickness of each layer. In the ball-on-disk test, the N-DLC mono-layer film showed the highest wear resistance; however, in the spherical polishing method, the eight-layer film showed the highest polishing resistance. The wear and polishing resistance and the aggressiveness against an opponent material of the multi-layer DLC films improved by reducing the thickness of a layer. In multi-layer films, the soft N-DLC layer between hard DLC layers is believed to function as a cushion. Thus, the tribological properties of the DLC films were improved by a multi-layered structure. The electrical resistivity of multi-layer DLC films was approximately half that of the DLC mono-layer film. Therefore, the periodic DLC/N-DLC eight-layer film is a good conductive hard-coating film.

Method for manufacturing electrical contacts for a thin-film semiconductor device

DOEpatents

Carlson, David E.; Dickson, Charles R.; D'Aiello, Robert V.

1988-11-08

A method of fabricating spaced-apart back contacts on a thin film of semiconductor material by forming strips of buffer material on top of the semiconductor material in locations corresponding to the desired dividing lines between back contacts, forming a film of metal substantially covering the semiconductor material and buffer strips, and scribing portions of the metal film overlying the buffer strips with a laser without contacting the underlying semiconductor material to separate the metal layer into a plurality of back contacts. The buffer material serves to protect the underlying semiconductor material from being damaged during the laser scribing. Back contacts and multi-cell photovoltaic modules incorporating such back contacts also are disclosed.

Green fabrication of composite cathode with attractive performance for solid oxide fuel cells through facile inkjet printing

NASA Astrophysics Data System (ADS)

Li, Chao; Chen, Huili; Shi, Huangang; Tade, Moses O.; Shao, Zongping

2015-01-01

The inkjet printing technique has numerous advantages and is attractive in solid oxide fuel cell (SOFC) fabrication, especially for the dense thin electrolyte layer because of its ultrafine powder size. In this study, we exploited the technique for the fabrication of a porous SDC/SSC composite cathode layer using environmentally friendly water-based ink. An optimized powder synthesis method was applied to the preparation of the well-dispersed suspension. In view of the easy sintering of the thin film layer prepared by inkjet printing, 10 wt.% pore former was introduced to the ink. The results indicate that the cell with the inkjet printing cathode layer exhibits a fantastic electrochemical performance, with a PPD as high as 940 mW cm-2 at 750 °C, which is comparable to that of a cell prepared using the conventional wet powder spraying method, suggesting a promising application of inkjet printing on electrode layer fabrication.

Multi-channel polarized thermal emitter

DOEpatents

Lee, Jae-Hwang; Ho, Kai-Ming; Constant, Kristen P

2013-07-16

A multi-channel polarized thermal emitter (PTE) is presented. The multi-channel PTE can emit polarized thermal radiation without using a polarizer at normal emergence. The multi-channel PTE consists of two layers of metallic gratings on a monolithic and homogeneous metallic plate. It can be fabricated by a low-cost soft lithography technique called two-polymer microtransfer molding. The spectral positions of the mid-infrared (MIR) radiation peaks can be tuned by changing the periodicity of the gratings and the spectral separation between peaks are tuned by changing the mutual angle between the orientations of the two gratings.

Recent developments in multi-layer flat knitting technology for waste free production of complex shaped 3D-reinforcing structures for composites

NASA Astrophysics Data System (ADS)

Trümper, W.; Lin, H.; Callin, T.; Bollengier, Q.; Cherif, C.; Krzywinski, S.

2016-07-01

Constantly increasing prices for raw materials and energy as well as the current discourse on the reduction of CO2-emissions places a special emphasis on the advantages of lightweight constructions and its resource conserving production methods. Fibre-reinforced composites are already seeing a number of applications in automobile, energy and mechanical engineering. Future applications within the named areas require greater material and energy efficiency and therefore manufacturing methods for textile preforms and lightweight constructions enabling an optimal arrangement of the reinforcing fibres while in the same time limiting waste to a minimum. One manufacturing method for textile reinforced preforms fulfilling quite many of the named requirements is the multilayer weft knitting technology. Multilayer weft knitted fabrics containing straight reinforcing yarns at least in two directions. The arrangement of these yarns is fixed by the loop yarn. Used yarn material in each knitting row is adaptable e. g. according to the load requirements or for the local integration of sensors. Draping properties of these fabrics can be varied within a great range and through this enabling draping of very complex shaped 3D-preforms without wrinkles from just one uncut fabric. The latest developments at ITM are concentrating on the development of a full production chain considering the 3D-CAD geometry, the load analysis, the generation of machine control programs as well as the development of technology and machines to enable the manufacturing of innovative net shape 3D-multilayer weft knitted fabrics such as complex shaped spacer fabrics and tubular fabrics with biaxial reinforcement.

Multi-functional Textiles for Military Applications

NASA Astrophysics Data System (ADS)

Malshe, Priyadarshini

The objective of this research was to develop the standard rip-stop weave military uniform fabric made of 50/50 nylon/cotton (NyCo) to achieve a repellent front surface and an antibacterial bulk for protection from chemical-biological warfare agents. Diallyldimethylammonium chloride (DADMAC), a quaternary ammonium salt monomer was graft polymerized on NyCo fabric to impart antimicrobial capability using atmospheric pressure glow discharge plasma. Plasma was used to induce free radical chain polymerization of the DADMAC monomer to introduce a graft polymerized network on the fabric with durable antimicrobial properties. Pentaerythritol tertraacrylate was used as a cross-linking agent to obtain a highly cross-linked, durable polymer network. The presence of polyDADMAC on the fabric surface was confirmed using acid dye staining, SEM, and TOF-SIMS. Antibacterial performance was evaluated using standard AATCC test method 100 for both gram positive and gram negative bacteria. Results showed 99.9% reduction in the bacterial activities of K. pneumoniae and S. aureus. To achieve repellency on NyCo front surface, an environmentally benign C6 fluorocarbon monomer, 2-(perfluorohexyl) ethyl acrylate was graft polymerized using plasma on the front surface of the NyCo fabric which was already grafted with polyDADMAC for anti-microbial properties. The surface was characterized by IR spectroscopy and XPS. The presence of fluorine on the surface was mapped and confirmed by TOF-SIMS. SEM images showed a uniform layer of fluorocarbon polymer on the fiber surface. High water contact angle of 144° was obtained on the surface. The surface also achieved a high AATCC Test Method 193 rating of 9 and AATCC Test Method 118 rating of 5, indicating that the surface could repel a fluid with surface tension as low as 24 dynes/cm. Appropriate experimental designs and statistical modeling of data helped identify the experimental space and optimal factor combinations for best response. The study helped create a multi-functional fabric with an anti-bacterial bulk, hydrophilic back surface and repellent front surface for enhanced protective and aesthetic values.

Investigation of the adhesion properties of direct 3D printing of polymers and nanocomposites on textiles: Effect of FDM printing process parameters

NASA Astrophysics Data System (ADS)

Hashemi Sanatgar, Razieh; Campagne, Christine; Nierstrasz, Vincent

2017-05-01

In this paper, 3D printing as a novel printing process was considered for deposition of polymers on synthetic fabrics to introduce more flexible, resource-efficient and cost effective textile functionalization processes than conventional printing process like screen and inkjet printing. The aim is to develop an integrated or tailored production process for smart and functional textiles which avoid unnecessary use of water, energy, chemicals and minimize the waste to improve ecological footprint and productivity. Adhesion of polymer and nanocomposite layers which were 3D printed directly onto the textile fabrics using fused deposition modeling (FDM) technique was investigated. Different variables which may affect the adhesion properties including 3D printing process parameters, fabric type and filler type incorporated in polymer were considered. A rectangular shape according to the peeling standard was designed as 3D computer-aided design (CAD) to find out the effect of the different variables. The polymers were printed in different series of experimental design: nylon on polyamide 66 (PA66) fabrics, polylactic acid (PLA) on PA66 fabric, PLA on PLA fabric, and finally nanosize carbon black/PLA (CB/PLA) and multi-wall carbon nanotubes/PLA (CNT/PLA) nanocomposites on PLA fabrics. The adhesion forces were quantified using the innovative sample preparing method combining with the peeling standard method. Results showed that different variables of 3D printing process like extruder temperature, platform temperature and printing speed can have significant effect on adhesion force of polymers to fabrics while direct 3D printing. A model was proposed specifically for deposition of a commercial 3D printer Nylon filament on PA66 fabrics. In the following, among the printed polymers, PLA and its composites had high adhesion force to PLA fabrics.

Layering garments during rest and exercise in the cold (8°C): wearer responses and comparability with selected fabric properties.

PubMed

MacRae, Braid A; Laing, Raechel M; Wilson, Cheryl A; Niven, Brian E

2014-01-01

How garments contribute to performance of the clothing system during wear is of interest, as is understanding the value of using fabric properties to inform end-use characteristics. To investigate the influences of layering upper-body garments, four fabrics were used to construct two first-layer garments (wool and polyester) and two outer-layer garments (wool and membrane laminate). Over six sessions, 10 moderately trained males wore each first-layer garment as a single layer and in combination with each outer-layer garment while resting, running and walking in cold environmental conditions (8 ± 1°C, 81 ± 4% RH). Here, the type of garment arrangement worn (fabric type or number of layers) had little influence on heart rate, core body temperature and change in body mass. Weighted mean covered skin temperature was warmer and weighted mean next-to-skin vapour pressure was typically higher (following the onset of exercise) with two layers versus one. Differences among fabrics for individual properties were typically overstated compared to differences among corresponding garments for physiological and psychophysical variables under the conditions of this study. These findings inform the interpretation of particular fabric properties and highlight issues to be acknowledged during development/refinement of fabric test methods. We examined the way in which selected fibre, fabric and garment (layering) characteristics contribute to performance of the clothing system during wear under cold conditions. Selected properties of the constituent fabrics were found to provide limited insight into how garments perform during wear under the conditions of this study.

The multi-layer multi-configuration time-dependent Hartree method for bosons: theory, implementation, and applications.

PubMed

Cao, Lushuai; Krönke, Sven; Vendrell, Oriol; Schmelcher, Peter

2013-10-07

We develop the multi-layer multi-configuration time-dependent Hartree method for bosons (ML-MCTDHB), a variational numerically exact ab initio method for studying the quantum dynamics and stationary properties of general bosonic systems. ML-MCTDHB takes advantage of the permutation symmetry of identical bosons, which allows for investigations of the quantum dynamics from few to many-body systems. Moreover, the multi-layer feature enables ML-MCTDHB to describe mixed bosonic systems consisting of arbitrary many species. Multi-dimensional as well as mixed-dimensional systems can be accurately and efficiently simulated via the multi-layer expansion scheme. We provide a detailed account of the underlying theory and the corresponding implementation. We also demonstrate the superior performance by applying the method to the tunneling dynamics of bosonic ensembles in a one-dimensional double well potential, where a single-species bosonic ensemble of various correlation strengths and a weakly interacting two-species bosonic ensemble are considered.

Manufacture of multi-layer woven preforms

NASA Technical Reports Server (NTRS)

Mohamed, M. H.; Zhang, Z.; Dickinson, L.

1988-01-01

This paper reviews current three-dimensional weaving processes and discusses a process developed at the Mars Mission Research Center of North Carolina State University to weave three-dimensional multilayer fabrics. The fabrics may vary in size and complexity from simple panels to T-section or I-section beams to large stiffened panels. Parameters such as fiber orientation, volume fraction of the fiber required in each direction, yarn spacings or density, etc., which determine the physical properties of the composites are discussed.

Novel fabrication method for 3D microstructures using surface-activated bonding and its application to micro-mechanical parts

NASA Astrophysics Data System (ADS)

Yamada, Takayuki; Takahashi, Mutsuya; Ozawa, Takashi; Tawara, Satoshi; Goto, Takayuki

2002-11-01

The purpose of this work is to demonstrate that a novel fabrication method for 3-D microstructures (FORMULA) is applicable to fabrication of micro mechanical parts with a large flexibility. This method is a kind of layer manufacturing method of thin films for metallic or dielectric microstructures using surface-activated bonding (SAB). The bonding interfaces of thin films are investigated by transmission electron microscope (TEM). Voids were observed at the interfaces of both pure aluminum films and Al-Cu alloy films. The ratio of void on the Al-Cu/Al-Cu interface is much larger than that of Al/Al interface, although the films have the same surface roughness of 3nm in Ra (average roughness). And approximately 10nm-thick amorphous intermediate layers were found at the interfaces. Furthermore, we have fabricated a micro gear of 900μm in diameter and 200μm in height, which is about ten times as large as our previous test pieces. Overhung structures such as a bridge structure and a cantilever were also fabricated without supporting layers beneath them.

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.

Deformation sensor based on polymer-supported discontinuous graphene multi-layer coatings

NASA Astrophysics Data System (ADS)

Carotenuto, G.; Schiavo, L.; Romeo, V.; Nicolais, L.

2014-05-01

Graphene can be conveniently used in the modification of polymer surfaces. Graphene macromolecules are perfectly transparent to the visible light and electrically conductive, consequently these two properties can be simultaneously provided to polymeric substrates by surface coating with thin graphene layers. In addition, such coating process provides the substrates of: water-repellence, higher surface hardness, low-friction, self-lubrication, gas-barrier properties, and many other functionalities. Polyolefins have a non-polar nature and therefore graphene strongly sticks on their surface. Nano-crystalline graphite can be used as graphene precursor in some chemical processes (e.g., graphite oxide synthesis by the Hummer method), in addition it can be directly applied to the surface of a polyolefin substrate (e.g., polyethylene) to cover it by a thin graphene multilayer. In particular, the nano-crystalline graphite perfectly exfoliate under the application of a combination of shear and friction forces and the produced graphene single-layers perfectly spread and adhere on the polyethylene substrate surface. Such polymeric materials can be used as ITO (indium-tin oxide) substitute and in the fabrication of different electronic devices. Here the fabrication of transparent resistive deformation sensors based on low-density polyethylene films coated by graphene multilayers is described. Such devices are very sensible and show a high reversible and reproducible behavior.

Integrated Flexible Electronic Devices Based on Passive Alignment for Physiological Measurement

PubMed Central

Ryu, Jin Hwa; Byun, Sangwon; Baek, In-Bok; Lee, Bong Kuk; Jang, Won Ick; Jang, Eun-Hye; Kim, Ah-Yung; Yu, Han Yung

2017-01-01

This study proposes a simple method of fabricating flexible electronic devices using a metal template for passive alignment between chip components and an interconnect layer, which enabled efficient alignment with high accuracy. An electrocardiogram (ECG) sensor was fabricated using 20 µm thick polyimide (PI) film as a flexible substrate to demonstrate the feasibility of the proposed method. The interconnect layer was fabricated by a two-step photolithography process and evaporation. After applying solder paste, the metal template was placed on top of the interconnect layer. The metal template had rectangular holes at the same position as the chip components on the interconnect layer. Rectangular hole sizes were designed to account for alignment tolerance of the chips. Passive alignment was performed by simply inserting the components in the holes of the template, which resulted in accurate alignment with positional tolerance of less than 10 µm based on the structural design, suggesting that our method can efficiently perform chip mounting with precision. Furthermore, a fabricated flexible ECG sensor was easily attachable to the curved skin surface and able to measure ECG signals from a human subject. These results suggest that the proposed method can be used to fabricate epidermal sensors, which are mounted on the skin to measure various physiological signals. PMID:28420219

Fabrication of AlN/BN bishell hollow nanofibers by electrospinning and atomic layer deposition

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

Haider, Ali; Kayaci, Fatma; Uyar, Tamer

2014-09-01

Aluminum nitride (AlN)/boron nitride (BN) bishell hollow nanofibers (HNFs) have been fabricated by successive atomic layer deposition (ALD) of AlN and sequential chemical vapor deposition (CVD) of BN on electrospun polymeric nanofibrous template. A four-step fabrication process was utilized: (i) fabrication of polymeric (nylon 6,6) nanofibers via electrospinning, (ii) hollow cathode plasma-assisted ALD of AlN at 100 °C onto electrospun polymeric nanofibers, (iii) calcination at 500 °C for 2 h in order to remove the polymeric template, and (iv) sequential CVD growth of BN at 450 °C. AlN/BN HNFs have been characterized for their chemical composition, surface morphology, crystal structure, and internal nanostructuremore » using X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and selected area electron diffraction. Measurements confirmed the presence of crystalline hexagonal BN and AlN within the three dimensional (3D) network of bishell HNFs with relatively low impurity content. In contrast to the smooth surface of the inner AlN layer, outer BN coating showed a highly rough 3D morphology in the form of BN nano-needle crystallites. It is shown that the combination of electrospinning and plasma-assisted low-temperature ALD/CVD can produce highly controlled multi-layered bishell nitride ceramic hollow nanostructures. While electrospinning enables easy fabrication of nanofibrous template, self-limiting reactions of plasma-assisted ALD and sequential CVD provide control over the wall thicknesses of AlN and BN layers with sub-nanometer accuracy.« less

Fabrication process for a gradient index x-ray lens

DOEpatents

Bionta, R.M.; Makowiecki, D.M.; Skulina, K.M.

1995-01-17

A process is disclosed for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments in the soft x-ray region. 13 figures.

Fabrication process for a gradient index x-ray lens

DOEpatents

Bionta, Richard M.; Makowiecki, Daniel M.; Skulina, Kenneth M.

1995-01-01

A process for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments m the soft x-ray region.

Development of Self-Cleaning Denim Fabrics

NASA Astrophysics Data System (ADS)

Uğur, Ş. S.; Sarıışık, A. M.; Çavuşlar, E.; Ertek, M.

2017-10-01

Denim fabrics coated with TiO2 nanolayers for self-cleaning properties by using a continuous layer-by-layer method. Nanolayer coated denim fabrics washed with an enzyme process for aging affect. Fabrics were analyzed with SEM-EDX and XPS measurements. Self-cleaning properties of the nanolayer deposited denim fabrics were tested according to red wine stain against to Suntest visible light irradiation after 72 h. And also, some physical (air permeability, tensile strength) and color (color difference and rubbing fastness) properties were evaluated.

MWCNT Coated Free-Standing Carbon Fiber Fabric for Enhanced Performance in EMI Shielding with a Higher Absolute EMI SE

PubMed Central

Pothupitiya Gamage, Sudesh Jayashantha; Yang, Kihun; Braveenth, Ramanaskanda; Raagulan, Kanthasamy; Kim, Hyun Suk; Lee, Yun Seon; Yang, Cheol-Min; Moon, Jai Jung; Chai, Kyu Yun

2017-01-01

A series of multi-walled carbon nanotube (MWCNT) coated carbon fabrics was fabricated using a facile dip coating process, and their performance in electrical conductivity, thermal stability, tensile strength, electromagnetic interference (EMI) and shielding effectiveness (SE) was investigated. A solution of MWCNT oxide and sodium dodecyl sulfate (SDS) in water was used in the coating process. MWCNTs were observed to coat the surfaces of carbon fibers and to fill the pores in the carbon fabric. Electrical conductivity of the composites was 16.42 S cm−1. An EMI shielding effectiveness of 37 dB at 2 GHz was achieved with a single layer of C/C composites, whereas the double layers resulted in 68 dB EMI SE at 2.7 GHz. Fabricated composites had a specific SE of 486.54 dB cm3 g−1 and an absolute SE of approximately 35,000 dB cm2 g−1. According to the above results, MWCNT coated C/C composites have the potential to be used in advanced shielding applications such as aerospace and auto mobile electronic devices.

Recent progress in the assembly of nanodevices and van der Waals heterostructures by deterministic placement of 2D materials.

PubMed

Frisenda, Riccardo; Navarro-Moratalla, Efrén; Gant, Patricia; Pérez De Lara, David; Jarillo-Herrero, Pablo; Gorbachev, Roman V; Castellanos-Gomez, Andres

2018-01-02

Designer heterostructures can now be assembled layer-by-layer with unmatched precision thanks to the recently developed deterministic placement methods to transfer two-dimensional (2D) materials. This possibility constitutes the birth of a very active research field on the so-called van der Waals heterostructures. Moreover, these deterministic placement methods also open the door to fabricate complex devices, which would be otherwise very difficult to achieve by conventional bottom-up nanofabrication approaches, and to fabricate fully-encapsulated devices with exquisite electronic properties. The integration of 2D materials with existing technologies such as photonic and superconducting waveguides and fiber optics is another exciting possibility. Here, we review the state-of-the-art of the deterministic placement methods, describing and comparing the different alternative methods available in the literature, and we illustrate their potential to fabricate van der Waals heterostructures, to integrate 2D materials into complex devices and to fabricate artificial bilayer structures where the layers present a user-defined rotational twisting angle.

Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

DOEpatents

Lessing, Paul A [Idaho Falls, ID

2008-07-22

An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

DOEpatents

Lessing, Paul A.

2004-09-07

An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

Fabrication of contacts for silicon solar cells including printing burn through layers

DOEpatents

Ginley, David S; Kaydanova, Tatiana; Miedaner, Alexander; Curtis, Calvin J; Van Hest, Marinus Franciscus Antonius Maria

2014-06-24

A method for fabricating a contact (240) for a solar cell (200). The method includes providing a solar cell substrate (210) with a surface that is covered or includes an antireflective coating (220). For example, the substrate (210) may be positioned adjacent or proximate to an outlet of an inkjet printer (712) or other deposition device. The method continues with forming a burn through layer (230) on the coating (220) by depositing a metal oxide precursor (e.g., using an inkjet or other non-contact printing method to print or apply a volume of liquid or solution containing the precursor). The method includes forming a contact layer (240) comprising silver over or on the burn through layer (230), and then annealing is performed to electrically connect the contact layer (240) to the surface of the solar cell substrate (210) through a portion of the burn through layer (230) and the coating (220).

Changing the thickness of two layers: i-ZnO nanorods, p-Cu2O and its influence on the carriers transport mechanism of the p-Cu2O/i-ZnO nanorods/n-IGZO heterojunction.

PubMed

Ke, Nguyen Huu; Trinh, Le Thi Tuyet; Phung, Pham Kim; Loan, Phan Thi Kieu; Tuan, Dao Anh; Truong, Nguyen Huu; Tran, Cao Vinh; Hung, Le Vu Tuan

2016-01-01

In this study, two layers: i-ZnO nanorods and p-Cu2O were fabricated by electrochemical deposition. The fabricating process was the initial formation of ZnO nanorods layer on the n-IGZO thin film which was prepared by sputtering method, then a p-Cu2O layer was deposited on top of rods to form the p-Cu2O/i-ZnO nanorods/n-ZnO heterojunction. The XRD, SEM, UV-VIS, I-V characteristics methods were used to define structure, optical and electrical properties of these heterojunction layers. The fabricating conditions and thickness of the Cu2O layers significantly affected to the formation, microstructure, electrical and optical properties of the junction. The length of i-ZnO nanorods layer in the structure of the heterojunction has strongly affected to the carriers transport mechanism and performance of this heterojunction.

An implemented method of asymmetric transmission for arbitrary polarization base in multi-layered chiral meta-surface

NASA Astrophysics Data System (ADS)

Xiao, Zhong-yin; Zou, Huan-ling; Xu, Kai-Kai; Tang, Jing-yao

2018-03-01

Asymmetric transmission of linearly or circularly polarized waves is a well-established property not only for three-layered chiral structures but for multi-layered ones. Here we show a method which can simultaneously implement asymmetric transmission for arbitrary base vector polarized wave in multi-layered chiral meta-surface. We systematically study the implemented method based on a multi-layered chiral structure consisting of a y-shape, a half gammadion and an S-shape in the terahertz gap. A numerical simulation was carried out, followed by an explanation of the asymmetric transmission mechanism in these structures proposed in this work. The simulated results indicate that the multi-layered chiral structure can realize a maximum asymmetric transmission of 0.89 and 0.28 for circularly and linearly polarized waves, respectively, which exhibit magnitude improvement over previous chiral metamaterials. Specifically, the maximum asymmetric transmitted coefficient of the multi-layered chiral structure is insensitivity to the incident angles from 0° to 45° for circularly polarized components. Additionally, we also study the influence of structural parameters on the asymmetric transmission effect for both linearly and circularly polarized waves in detail.

Electrically Tunable and Negative Schottky Barriers in Multi-layered Graphene/MoS2 Heterostructured Transistors.

PubMed

Qiu, Dongri; Kim, Eun Kyu

2015-09-03

We fabricated multi-layered graphene/MoS2 heterostructured devices by positioning mechanically exfoliated bulk graphite and single-crystalline 2H-MoS2 onto Au metal pads on a SiO2/Si substrate via a contamination-free dry transfer technique. We also studied the electrical transport properties of Au/MoS2 junction devices for systematic comparison. A previous work has demonstrated the existence of a positive Schottky barrier height (SBH) in the metal/MoS2 system. However, analysis of the SBH indicates that the contacts of the multi-layered graphene/MoS2 have tunable negative barriers in the range of 300 to -46 meV as a function of gate voltage. It is hypothesized that this tunable SBH is responsible for the modulation of the work function of the thick graphene in these devices. Despite the large number of graphene layers, it is possible to form ohmic contacts, which will provide new opportunities for the engineering of highly efficient contacts in flexible electronics and photonics.

Electrically Tunable and Negative Schottky Barriers in Multi-layered Graphene/MoS2 Heterostructured Transistors

NASA Astrophysics Data System (ADS)

Qiu, Dongri; Kim, Eun Kyu

2015-09-01

We fabricated multi-layered graphene/MoS2 heterostructured devices by positioning mechanically exfoliated bulk graphite and single-crystalline 2H-MoS2 onto Au metal pads on a SiO2/Si substrate via a contamination-free dry transfer technique. We also studied the electrical transport properties of Au/MoS2 junction devices for systematic comparison. A previous work has demonstrated the existence of a positive Schottky barrier height (SBH) in the metal/MoS2 system. However, analysis of the SBH indicates that the contacts of the multi-layered graphene/MoS2 have tunable negative barriers in the range of 300 to -46 meV as a function of gate voltage. It is hypothesized that this tunable SBH is responsible for the modulation of the work function of the thick graphene in these devices. Despite the large number of graphene layers, it is possible to form ohmic contacts, which will provide new opportunities for the engineering of highly efficient contacts in flexible electronics and photonics.

Hybrid Mixed Media Nonwovens: An Investigation of Structure-Property Relationships

NASA Astrophysics Data System (ADS)

Hollowell, Kendall Birckhead

There have been myriad studies on utilizing bicomponent splittables produced through spunbond/spunlace processes. These production methods have proven to yield microfibers which increase the surface area of the nonwoven structures. There has been recent focus on studying the microfibers within these nonwoven structures as well as using a multiplicity of deniers of fibers within the nonwoven. There have also been studies on producing nonwovens with fibers of differing cross-sectional shapes and diameters. The purpose of this study is to examine the properties of a nonwoven structure, marrying the concepts of multi-denier fibers with multi-shaped fibers in two configurations: three-layer and alternating. The basis for this study will be US Patent 6,964,931 B2 "Method of making Continuous Filament Web with Statistical Filament Distribution" as well as US Patent 7,981,336 B2 "Process of Making Mixed Fibers and Nonwoven Fabrics". This study addresses the melt-spinning and hydroentanglement of nonwoven webs made from bicomponent fibers in three-layer and alternating configurations. The bicomponent cross-sections that will be used include 16-segmented pie and 7-islands-in-the-sea. In this study the establishment of the utility of mixed media nonwovens will take place through property and structure analysis in order to determine the inherent properties of the mixed media structures as well as the structure-property relationships of the nonwoven fabric. Property and structure analysis will also take place on mixed media structures containing poly(lactic acid) as a sacrificial component in the bicomponent fiber after optimizing the removal conditions of the poly(lactic acid) in a sodium hydroxide (NaOH) bath.

Sedimentation, bioturbation, and sedimentary fabric evolution on a modern mesotidal mudflat: A multi-tracer study of processes, rates, and scales

NASA Astrophysics Data System (ADS)

Bentley, Samuel J.; Swales, Andrew; Pyenson, Benjamin; Dawe, Justin

2014-03-01

A study of muddy tidal-flat sedimentation and bioturbation was undertaken in the Waitetuna Arm of Raglan Harbor, New Zealand, to evaluate the physical and biological processes that control cycling of sediment between the intertidal seabed and sediment-water interface, and also the formation of tidal flat sedimentary fabric and fine-scale stratigraphy. Cores were collected along an intertidal transect, and analyzed for sedimentary fabric, 210Pb and 7Be radiochemical distributions, and grain size. At the same locations, a new approach for time-series core-X-radiography study was undertaken (spanning 191 days), using magnetite-rich sand as a tracer for sedimentation and bioturbation processes in shallow tidal flat sediments. Sedimentary fabric consists of a shallow stratified layer overlying a deeper zone of intensely bioturbated shelly mud. Bioadvection mixes the deeper zone and contributes fine sediment to the surface stratified layer, via biodeposition. Physical resuspension and deposition of surface muds by wave and tidal flow are also likely contributors to formation of the surficial stratified layer, but physical stratification is not observed below this depth. The deliberate tracer study allowed calculation of bioadvection rates that control strata formation, and can be used to model diagenetic processes. Results suggest that the upper ˜15 cm of seabed can be fully mixed over timescales <1.75 y. Such mixing will erase pre-existing sedimentary fabric and transport buried sediment and chemical compounds back to the tidal-flat surface. Shallow biodiffusion also exists, but produces much slower and shallower mass transport. Best fits for 210Pb profiles using a diagenetic bioadvection/sedimentation model and independently measured tiered bioadvection rates suggest that sediment accumulation rates (SARs) on the tidal flat are ˜0.25 cm/y, near the low end of contemporary New Zealand muddy intertidal SARs. Frequent deposition and erosion of the surface layer demonstrates that long-term sediment accumulation captures only a small fraction of sediment deposited at any one time. Model results also suggest that our magnetite tracer method may slightly underestimate short-term shallow mixing rates (demonstrated by 7Be profiles), and slightly overestimate longer-term, deeper bioturbation rates (demonstrated by 210Pb profiles).

Multi-layer seal for electrochemical devices

DOEpatents

Chou, Yeong-Shyung [Richland, WA; Meinhardt, Kerry D [Kennewick, WA; Stevenson, Jeffry W [Richland, WA

2010-11-16

Multi-layer seals are provided that find advantageous use for reducing leakage of gases between adjacent components of electrochemical devices. Multi-layer seals of the invention include a gasket body defining first and second opposing surfaces and a compliant interlayer positioned adjacent each of the first and second surfaces. Also provided are methods for making and using the multi-layer seals, and electrochemical devices including said seals.

Multi-layer seal for electrochemical devices

DOEpatents

Chou, Yeong-Shyung [Richland, WA; Meinhardt, Kerry D [Kennewick, WA; Stevenson, Jeffry W [Richland, WA

2010-09-14

Multi-layer seals are provided that find advantageous use for reducing leakage of gases between adjacent components of electrochemical devices. Multi-layer seals of the invention include a gasket body defining first and second opposing surfaces and a compliant interlayer positioned adjacent each of the first and second surfaces. Also provided are methods for making and using the multi-layer seals, and electrochemical devices including said seals.

High energy PIXE: A tool to characterize multi-layer thick samples

NASA Astrophysics Data System (ADS)

Subercaze, A.; Koumeir, C.; Métivier, V.; Servagent, N.; Guertin, A.; Haddad, F.

2018-02-01

High energy PIXE is a useful and non-destructive tool to characterize multi-layer thick samples such as cultural heritage objects. In a previous work, we demonstrated the possibility to perform quantitative analysis of simple multi-layer samples using high energy PIXE, without any assumption on their composition. In this work an in-depth study of the parameters involved in the method previously published is proposed. Its extension to more complex samples with a repeated layer is also presented. Experiments have been performed at the ARRONAX cyclotron using 68 MeV protons. The thicknesses and sequences of a multi-layer sample including two different layers of the same element have been determined. Performances and limits of this method are presented and discussed.

Fabrication of microchannels in polycrystalline diamond using pre-fabricated Si substrates

NASA Astrophysics Data System (ADS)

Chandran, Maneesh; Elfimchev, Sergey; Michaelson, Shaul; Akhvlediani, Rozalia; Ternyak, Orna; Hoffman, Alon

2017-10-01

In this paper, we report on a simple, feasible method to fabricate microchannels in diamond. Polycrystalline diamond microchannels were produced by fabricating trenches in a Si wafer and subsequently depositing a thin layer of diamond onto this substrate using the hot filament vapor deposition technique. Fabrication of trenches in the Si substrate at different depths was carried out by standard photolithography, and the subsequent deposition of the diamond layer was performed by the hot filament chemical vapor deposition technique. The growth mechanism of diamond that leads to the formation of closed diamond microchannels is discussed in detail based on the Knudsen number and growth chemistry of diamond. Variations in the crystallite size, crystalline quality, and thickness of the diamond layer along the trench depths were systematically analyzed using cross-sectional scanning electron microscopy and Raman spectroscopy. Defect density and formation of non-diamond forms of carbon in the diamond layer were found to increase with the trench depth, which sets a limit of 5-45 μm trench depth (or an aspect ratio of 1-9) for the fabrication of diamond microchannels using this method under the present conditions.

Design and fabrication of a reflection far ultraviolet polarizer and retarder

NASA Technical Reports Server (NTRS)

Kim, Jongmin; Zukic, Muamer; Wilson, Michele M.; Torr, Douglas G.

1993-01-01

New methods have been developed for the design of a far ultraviolet multilayer reflection polarizer and retarder. A MgF2/Al/MgF2 three-layer structure deposited on a thick opaque Al film (substrate) is used for the design of polarizers and retarders. The induced transmission and absorption method is used for the design of a polarizer and layer-by-layer electric field calculation method is used for the design of a quarterwave retarder. In order to fabricate these designs in a conventional high vacuum chamber, we have to minimize the oxidation of the Al layers and somehow characterize the oxidized layer. X-ray photoelectron spectroscopy is used to investigate the amount and profile of oxidation. Depth profiling results and a seven layer oxidation model are presented.

Multi-level diffractive optics for single laser exposure fabrication of telecom-band diamond-like 3-dimensional photonic crystals.

PubMed

Chanda, Debashis; Abolghasemi, Ladan E; Haque, Moez; Ng, Mi Li; Herman, Peter R

2008-09-29

We present a novel multi-level diffractive optical element for diffractive optic near-field lithography based fabrication of large-area diamond-like photonic crystal structure in a single laser exposure step. A multi-level single-surface phase element was laser fabricated on a thin polymer film by two-photon polymerization. A quarter-period phase shift was designed into the phase elements to generate a 3D periodic intensity distribution of double basis diamond-like structure. Finite difference time domain calculation of near-field diffraction patterns and associated isointensity surfaces are corroborated by definitive demonstration of a diamond-like woodpile structure formed inside thick photoresist. A large number of layers provided a strong stopband in the telecom band that matched predictions of numerical band calculation. SEM and spectral observations indicate good structural uniformity over large exposure area that promises 3D photonic crystal devices with high optical quality for a wide range of motif shapes and symmetries. Optical sensing is demonstrated by spectral shifts of the Gamma-Zeta stopband under liquid emersion.

Cylindrical cryogenic calorimeter testing of six types of multilayer insulation systems

NASA Astrophysics Data System (ADS)

Fesmire, J. E.; Johnson, W. L.

2018-01-01

Extensive cryogenic thermal testing of more than 100 different multilayer insulation (MLI) specimens was performed over the last 20 years for the research and development of evacuated reflective thermal insulation systems. From this data library, 26 MLI systems plus several vacuum-only systems are selected for analysis and comparison. The test apparatus, methods, and results enabled the adoption of two new technical consensus standards under ASTM International. Materials tested include reflectors of aluminum foil or double-aluminized Mylar and spacers of fiberglass paper, polyester netting, silk netting, polyester fabric, or discrete polymer standoffs. The six types of MLI systems tested are listed as follows: Mylar/Paper, Foil/Paper, Mylar/Net, Mylar/Blanket, Mylar/Fabric, Mylar/Discrete. Also tested are vacuum-only systems with different cold surface materials/finishes including stainless steel, black, copper, and aluminum. Testing was performed between the boundary temperatures of 78 K and 293 K (and up to 350 K) using a thermally guarded one-meter-long cylindrical calorimeter (Cryostat-100) for absolute heat flow measurement. Cold vacuum pressures include the full range from 1 × 10-6 torr to 760 torr with nitrogen as the residual gas. System variations include number of layers from one to 80 layers, layer densities from 0.5 to 5 layers per millimeter, and installation techniques such layer-by-layer, blankets (multi-layer assemblies), sub-blankets, seaming, butt-joining, spiral wrapping, and roll-wrapping. Experimental thermal performance data for the different MLI systems are presented in terms of heat flux and effective thermal conductivity. Benchmark cryogenic-vacuum thermal performance curves for MLI are given for comparison with different insulation approaches for storage and transfer equipment, cryostats, launch vehicles, spacecraft, or science instruments.

Micro-fabricated integrated coil and magnetic circuit and method of manufacturing thereof

DOEpatents

Mihailovich, Robert E.; Papavasiliou, Alex P.; Mehrotra, Vivek; Stupar, Philip A.; Borwick, III, Robert L.; Ganguli, Rahul; DeNatale, Jeffrey F.

2017-03-28

A micro-fabricated electromagnetic device is provided for on-circuit integration. The electromagnetic device includes a core. The core has a plurality of electrically insulating layers positioned alternatingly between a plurality of magnetic layers to collectively form a continuous laminate having alternating magnetic and electrically insulating layers. The electromagnetic device includes a coil embedded in openings of the semiconductor substrate. An insulating material is positioned in the cavity and between the coil and an inner surface of the core. A method of manufacturing the electromagnetic device includes providing a semiconductor substrate having openings formed therein. Windings of a coil are electroplated and embedded in the openings. The insulating material is coated on or around an exposed surface of the coil. Alternating magnetic layers and electrically insulating layers may be micro-fabricated and electroplated as a single and substantially continuous segment on or around the insulating material.

Nanoparticle embedded p-type electrodes for GaN-based flip-chip light emitting diodes.

PubMed

Kwak, Joon Seop; Song, J O; Seong, T Y; Kim, B I; Cho, J; Sone, C; Park, Y

2006-11-01

We have investigated high-quality ohmic contacts for flip-chip light emitting diodes using Zn-Ni nanoparticles/Ag schemes. The Zn-Ni nanoparticles/Ag contacts produce specific contact resistances of 10(-5)-10(-6) omegacm2 when annealed at temperatures of 330-530 degrees C for 1 min in air ambient, which are much better than those obtained from the Ag contacts. It is shown that blue InGaN/GaN multi-quantum well light emitting diodes fabricated with the annealed Zn-Ni nanoparticles/Ag contacts give much lower forward-bias voltages at 20 mA compared with those of the multi-quantum well light emitting diodes made with the as-deposited Ag contacts. It is further presented that the multi-quantum well light emitting diodes made with the Zn-Ni nanoparticles/Ag contacts show similar output power compared to those fabricated with the Ag contact layers.

Teflon/SiO₂ Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process.

PubMed

Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Hung, Bohr-Ran

2015-04-13

This study proposes a two-photomask process for fabricating amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO₂ combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO₂ deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity.

Method of fabricating reflection-mode EUV diffusers

DOEpatents

Anderson, Erik; Naulleau, Patrick P.

2005-03-01

Techniques for fabricating well-controlled, random relief, engineered surfaces that serve as substrates for EUV optical devices are accomplished with grayscale exposure. The method of fabricating a multilevel EUV optical element includes: (a) providing a substrate; (b) depositing a layer of curable material on a surface of the substrate; (c) creating a relief profile in a layer of cured material from the layer of curable material wherein the relief profile comprises multiple levels of cured material that has a defined contour; and (d) depositing a multilayer reflection film over the relief profile wherein the film has an outer contour that substantially matches that of the relief profile. The curable material can comprise photoresist or a low dielectric constant material.

Fabrication and Structural Characterization of an Ultrathin Film of a Two-Dimensional-Layered Metal-Organic Framework, {Fe(py)2[Ni(CN)4]} (py = pyridine).

PubMed

Sakaida, Shun; Haraguchi, Tomoyuki; Otsubo, Kazuya; Sakata, Osami; Fujiwara, Akihiko; Kitagawa, Hiroshi

2017-07-17

We report the fabrication and characterization of the first example of a tetracyanonickelate-based two-dimensional-layered metal-organic framework, {Fe(py) 2 Ni(CN) 4 } (py = pyridine), thin film. To fabricate a nanometer-sized thin film, we utilized the layer-by-layer method, whereby a substrate was alternately soaked in solutions of the structural components. Surface X-ray studies revealed that the fabricated film was crystalline with well-controlled growth directions both parallel and perpendicular to the substrate. In addition, lattice parameter analysis indicated that the crystal system is found to be close to higher symmetry by being downsized to a thin film.

An improved multi-exposure approach for high quality holographic femtosecond laser patterning

NASA Astrophysics Data System (ADS)

Zhang, Chenchu; Hu, Yanlei; Li, Jiawen; Lao, Zhaoxin; Ni, Jincheng; Chu, Jiaru; Huang, Wenhao; Wu, Dong

2014-12-01

High efficiency two photon polymerization through single exposure via spatial light modulator (SLM) has been used to decrease the fabrication time and rapidly realize various micro/nanostructures, but the surface quality remains a big problem due to the speckle noise of optical intensity distribution at the defocused plane. Here, a multi-exposure approach which used tens of computer generate holograms successively loaded on SLM is presented to significantly improve the optical uniformity without losing efficiency. By applying multi-exposure, we found that the uniformity at the defocused plane was increased from ˜0.02 to ˜0.6 according to our simulation. The fabricated two series of letters "HELLO" and "USTC" under single-and multi-exposure in our experiment also verified that the surface quality was greatly improved. Moreover, by this method, several kinds of beam splitters with high quality, e.g., 2 × 2, 5 × 5 Daman, and complex nonseperate 5 × 5, gratings were fabricated with both of high quality and short time (<1 min, 95% time-saving). This multi-exposure SLM-two-photon polymerization method showed the promising prospect in rapidly fabricating and integrating various binary optical devices and their systems.

Degradation and biocompatibility of multi-stage nanovectors in physiological systems

PubMed Central

Martinez, Jonathan O.; Evangelopoulos, Michael; Chiappini, Ciro; Liu, Xuewu; Ferrari, Mauro; Tasciotti, Ennio

2014-01-01

The careful scrutiny of drug delivery systems is essential to evaluate and justify their potential for the clinic. Among the various studies necessary for pre-clinical testing, the impact of degradation is commonly overlooked. In this paper, we investigate the effect of fabrication (porosity and nucleation layer) and environment (buffer and pH) factors on the degradation kinetics of multi-stage nanovectors (MSV) composed of porous silicon. The degradation by-products of MSV were exposed to endothelial cells and analyzed for detrimental effects on cellular internalization, architecture, proliferation, and cell cycle. Increases in porosity resulted in accelerated degradation exhibiting smaller sized particles at comparable times. Removal of the nucleation layer (thin layer of small pores formed during the initial steps of etching) triggered a premature collapse of the entire central porous region of MSV. Variations in buffers prompted a faster degradation rate yielding smaller MSV within faster time frames while increases in pH stimulated erosion of MSV and thus faster degradation. In addition, exposure to these degradation by-products provoked negligible impact on the proliferation and cell cycle phases on primary endothelial cells. Here, we propose methods that lay the foundation for future investigations towards understanding the impact of the degradation of drug delivery platforms. PMID:25269799

Multi-Dimensional Sensors and Sensing Systems

NASA Technical Reports Server (NTRS)

Stetter, Joseph R. (Inventor); Shirke, Amol G. (Inventor)

2014-01-01

A universal microelectromechanical (MEMS) nano-sensor platform having a substrate and conductive layer deposited in a pattern on the surface to make several devices at the same time, a patterned insulation layer, wherein the insulation layer is configured to expose one or more portions of the conductive layer, and one or more functionalization layers deposited on the exposed portions of the conductive layer to make multiple sensing capability on a single MEMS fabricated device. The functionalization layers are adapted to provide one or more transducer sensor classes selected from the group consisting of: radiant, electrochemical, electronic, mechanical, magnetic, and thermal sensors for chemical and physical variables and producing more than one type of sensor for one or more significant parameters that need to be monitored.

An efficient enzyme-powered micromotor device fabricated by cyclic alternate hybridization assembly for DNA detection.

PubMed

Fu, Shizhe; Zhang, Xueqing; Xie, Yuzhe; Wu, Jie; Ju, Huangxian

2017-07-06

An efficient enzyme-powered micromotor device was fabricated by assembling multiple layers of catalase on the inner surface of a poly(3,4-ethylenedioxythiophene and sodium 4-styrenesulfonate)/Au microtube (PEDOT-PSS/Au). The catalase assembly was achieved by programmed DNA hybridization, which was performed by immobilizing a designed sandwich DNA structure as the sensing unit on the PEDOT-PSS/Au, and then alternately hybridizing with two assisting DNA to bind the enzyme for efficient motor motion. The micromotor device showed unique features of good reproducibility, stability and motion performance. Under optimal conditions, it showed a speed of 420 μm s -1 in 2% H 2 O 2 and even 51 μm s -1 in 0.25% H 2 O 2 . In the presence of target DNA, the sensing unit hybridized with target DNA to release the multi-layer DNA as well as the multi-catalase, resulting in a decrease of the motion speed. By using the speed as a signal, the micromotor device could detect DNA from 10 nM to 1 μM. The proposed micromotor device along with the cyclic alternate DNA hybridization assembly technique provided a new path to fabricate efficient and versatile micromotors, which would be an exceptional tool for rapid and simple detection of biomolecules.

Fabrication of a 20.5-inch-diameter segmented silicon annular optic prototype for the ROMA program

NASA Astrophysics Data System (ADS)

Hassell, Frank R.; Groark, Frank M.

1995-10-01

Recent advancements in single crystal silicon material science and fabrication capabilities and very low absorption (VLA) multi-layer dielectric coating technology have led to the development of uncooled, large aperture, high power mirrors for high energy laser (HEL) systems. Based on this success, a segmented single-crystal silicon substrate concept has been selected as the baseline fabrication approach for uncooled 1.2 meter diameter resonator annular optics for the Alpha space based high energy laser. The objective of this Resonator Optics Materials Assessment (ROMA) task was to demonstrate all of the key fabrication processes required to fabricate the full sized annular optics for the Alpha space based high energy laser. This paper documents the fabrication of a half-scale annular optic prototype (AOP) of the Alpha laser rear cone.

Light Absorption Enhancement of Silicon-Based Photovoltaic Devices with Multiple Bandgap Structures of Porous Silicon

PubMed Central

Wu, Kuen-Hsien; Li, Chong-Wei

2015-01-01

Porous-silicon (PS) multi-layered structures with three stacked PS layers of different porosity were prepared on silicon (Si) substrates by successively tuning the electrochemical-etching parameters in an anodization process. The three PS layers have different optical bandgap energy and construct a triple-layered PS (TLPS) structure with multiple bandgap energy. Photovoltaic devices were fabricated by depositing aluminum electrodes of Schottky contacts on the surfaces of the developed TLPS structures. The TLPS-based devices exhibit broadband photoresponses within the spectrum of the solar irradiation and get high photocurrent for the incident light of a tungsten lamp. The improved spectral responses of devices are owing to the multi-bandgap structures of TLPS, which are designed with a layered configuration analog to a tandem cell for absorbing a wider energy range of the incidental sun light. The large photocurrent is mainly ascribed to an enhanced light-absorption ability as a result of applying nanoporous-Si thin films as the surface layers to absorb the short-wavelength light and to improve the Schottky contacts of devices. Experimental results reveal that the multi-bandgap PS structures produced from electrochemical-etching of Si wafers are potentially promising for development of highly efficient Si-based solar cells. PMID:28793542

Enhancing the imaging quality and fabrication efficiency of bionic compound eyes using a sandwich structure

NASA Astrophysics Data System (ADS)

Luo, Jiasai; Guo, Yongcai; Wang, Xin

2018-06-01

This paper puts forward a novel method for fabrication of sandwich-structured BCE using a detachable micro-hole array (MHA) prepared by 3D printing. Compared with most traditional methods, 3D printing enables effective implementation of direct micro-fabrication for curved BCE without the pattern transfer and substrate reshaping process. This 3D fabrication method allows rapid fabrication of the curved BCE and automatic assembly of the detachable MHA using a custom-built mold under negative pressure. The formation of a multi-focusing micro-lens array (MLA) was realized by adjusting the parameters of the curved detachable MHA. The imaging performance was effectively enhanced by the sandwich structure that consist of the multi-focusing MLA, the outer detachable MHA and the inner solidified MHA. This method is suitable for mass production due to its advantages as a time-saving, cost-effective and simple process. Optical design software was used to analyze the optical properties, and an imaging simulation was performed.

Method of manufacture of atomically thin boron nitride

DOEpatents

Zettl, Alexander K

2013-08-06

The present invention provides a method of fabricating at least one single layer hexagonal boron nitride (h-BN). In an exemplary embodiment, the method includes (1) suspending at least one multilayer boron nitride across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure. The present invention also provides a method of fabricating single layer hexagonal boron nitride. In an exemplary embodiment, the method includes (1) providing multilayer boron nitride suspended across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure.

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.

Layered nano-gratings by electron beam writing to form 3-level diffractive optical elements for 3D phase-offset holographic lithography.

PubMed

Yuan, Liang Leon; Herman, Peter R

2015-12-21

A multi-level nanophotonic structure is a major goal in providing advanced optical functionalities as found in photonic crystals and metamaterials. A three-level nano-grating phase mask has been fabricated in an electron-beam resist (ma-N) to meet the requirement of holographic generation of a diamond-like 3D nanostructure in photoresist by a single exposure step. A 2D mask with 600 nm periodicity is presented for generating first order diffracted beams with a preferred π/2 phase shift on the X- and Y-axes and with sufficient 1(st) order diffraction efficiency of 3.5% at 800 nm wavelength for creating a 3D periodic nanostructure in SU-8 photoresist. The resulting 3D structure is anticipated to provide an 8% complete photonic band gap (PBG) upon silicon inversion. A thin SiO2 layer was used to isolate the grating layers and multiple spin-coating steps served to planarize the final resist layer. A reversible soft coating (aquaSAVE) was introduced to enable SEM inspection and verification of each insulating grating layer. This e-beam lithographic method is extensible to assembling multiple layers of a nanophotonic structure.

Design and Fabrication of High-Efficiency CMOS/CCD Imagers

NASA Technical Reports Server (NTRS)

Pain, Bedabrata

2007-01-01

An architecture for back-illuminated complementary metal oxide/semiconductor (CMOS) and charge-coupled-device (CCD) ultraviolet/visible/near infrared- light image sensors, and a method of fabrication to implement the architecture, are undergoing development. The architecture and method are expected to enable realization of the full potential of back-illuminated CMOS/CCD imagers to perform with high efficiency, high sensitivity, excellent angular response, and in-pixel signal processing. The architecture and method are compatible with next-generation CMOS dielectric-forming and metallization techniques, and the process flow of the method is compatible with process flows typical of the manufacture of very-large-scale integrated (VLSI) circuits. The architecture and method overcome all obstacles that have hitherto prevented high-yield, low-cost fabrication of back-illuminated CMOS/CCD imagers by use of standard VLSI fabrication tools and techniques. It is not possible to discuss the obstacles in detail within the space available for this article. Briefly, the obstacles are posed by the problems of generating light-absorbing layers having desired uniform and accurate thicknesses, passivation of surfaces, forming structures for efficient collection of charge carriers, and wafer-scale thinning (in contradistinction to diescale thinning). A basic element of the present architecture and method - the element that, more than any other, makes it possible to overcome the obstacles - is the use of an alternative starting material: Instead of starting with a conventional bulk-CMOS wafer that consists of a p-doped epitaxial silicon layer grown on a heavily-p-doped silicon substrate, one starts with a special silicon-on-insulator (SOI) wafer that consists of a thermal oxide buried between a lightly p- or n-doped, thick silicon layer and a device silicon layer of appropriate thickness and doping. The thick silicon layer is used as a handle: that is, as a mechanical support for the device silicon layer during micro-fabrication.

Multi-domain boundary element method for axi-symmetric layered linear acoustic systems

NASA Astrophysics Data System (ADS)

Reiter, Paul; Ziegelwanger, Harald

2017-12-01

Homogeneous porous materials like rock wool or synthetic foam are the main tool for acoustic absorption. The conventional absorbing structure for sound-proofing consists of one or multiple absorbers placed in front of a rigid wall, with or without air-gaps in between. Various models exist to describe these so called multi-layered acoustic systems mathematically for incoming plane waves. However, there is no efficient method to calculate the sound field in a half space above a multi layered acoustic system for an incoming spherical wave. In this work, an axi-symmetric multi-domain boundary element method (BEM) for absorbing multi layered acoustic systems and incoming spherical waves is introduced. In the proposed BEM formulation, a complex wave number is used to model absorbing materials as a fluid and a coordinate transformation is introduced which simplifies singular integrals of the conventional BEM to non-singular radial and angular integrals. The radial and angular part are integrated analytically and numerically, respectively. The output of the method can be interpreted as a numerical half space Green's function for grounds consisting of layered materials.

A new UV-curing elastomeric substrate for rapid prototyping of microfluidic devices

NASA Astrophysics Data System (ADS)

Alvankarian, Jafar; Yeop Majlis, Burhanuddin

2012-03-01

Rapid prototyping in the design cycle of new microfluidic devices is very important for shortening time-to-market. Researchers are facing the challenge to explore new and suitable substrates with simple and efficient microfabrication techniques. In this paper, we introduce and characterize a UV-curing elastomeric polyurethane methacrylate (PUMA) for rapid prototyping of microfluidic devices. The swelling and solubility of PUMA in different chemicals is determined. Time-dependent measurements of water contact angle show that the native PUMA is hydrophilic without surface treatment. The current monitoring method is used for measurement of the electroosmotic flow mobility in the microchannels made from PUMA. The optical, physical, thermal and mechanical properties of PUMA are evaluated. The UV-lithography and molding process is used for making micropillars and deep channel microfluidic structures integrated to the supporting base layer. Spin coating is characterized for producing different layer thicknesses of PUMA resin. A device is fabricated and tested for examining the strength of different bonding techniques such as conformal, corona treating and semi-curing of two PUMA layers in microfluidic application and the results show that the bonding strengths are comparable to that of PDMS. We also report fabrication and testing of a three-layer multi inlet/outlet microfluidic device including a very effective fluidic interconnect for application demonstration of PUMA as a promising new substrate. A simple micro-device is developed and employed for observing the pressure deflection of membrane made from PUMA as a very effective elastomeric valve in microfluidic devices.

Electrochemical layer-by-layer approach to fabricate mechanically stable platinum black microelectrodes using a mussel-inspired polydopamine adhesive.

PubMed

Kim, Raeyoung; Nam, Yoonkey

2015-04-01

Platinum black (PtBK) has long been used for microelectrode fabrication owing to its high recording performance of neural signals. The porous structure of PtBK enlarges the surface area and lowers the impedance, which results in background noise reduction. However, the brittleness of PtBK has been a problem in practice. In this work, we report mechanically stable PtBK microelectrodes using a bioinspired adhesive film, polydopamine (pDA), while maintaining the low impedance of PtBK. The pDA layer was incorporated into the PtBK structure through electrochemical layer-by-layer deposition. Varying the number of layers and the order of materials, multi-layered pDA-PtBK hybrids were fabricated and the electrical properties, both impedance and charge injection limit, were evaluated. Multilayered pDA-PtBK hybrids had electrical impedances as low as PtBK controls and charge injection limit twice larger than controls. For the 30 min-ultrasonication agitation test, impedance levels rarely changed for some of the pDA-PtBK hybrids indicating that the pDA improved the mechanical property of the PtBK structures. The pDA-PtBK hybrid microelectrodes readily recorded neural signals of cultured hippocampal neurons, where background noise levels and signal-to-noise were 2.43 ∼ 3.23 μVrms and 28.4 ∼ 69.1, respectively. The developed pDA-PtBK hybrid microelectrodes are expected to be applicable to neural sensors for neural prosthetic studies.

Reliable fabrication of plasmonic nanostructures without an adhesion layer using dry lift-off

NASA Astrophysics Data System (ADS)

Chen, Yiqin; Li, Zhiqin; Xiang, Quan; Wang, Yasi; Zhang, Zhiqiang; Duan, Huigao

2015-10-01

Lift-off is the most commonly used pattern-transfer method to define lithographic plasmonic metal nanostructures. A typical lift-off process is realized by dissolving patterned resists in solutions, which has the limits of low yield when not using adhesion layers and incompatibility with the fabrication of some specific structures and devices. In this work, we report an alternative ‘dry’ lift-off process to obtain metallic nanostructures via mechanical stripping by using the advantage of poor adhesion between resists and noble metal films. We show that this dry stripping lift-off method is effective for both positive- and negative-tone resists to fabricate sparse and densely-packed plasmonic nanostructures, respectively. In particular, this method is achieved without using an adhesion layer, which enables the mitigation of plasmon damping to obtain larger field enhancement. Dark-field scattering, one-photon luminescence and surface-enhanced Raman scattering measurements were performed to demonstrate the improved quality factor of the plasmonic nanostructures fabricated by this dry lift-off process.

Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

DOEpatents

Norem, James H.; Pellin, Michael J.

2013-06-11

Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

Fabrication of graphene/titanium carbide nanorod arrays for chemical sensor application.

PubMed

Fu, Chong; Li, Mingji; Li, Hongji; Li, Cuiping; Qu, Changqing; Yang, Baohe

2017-03-01

Vertically stacked graphene nanosheet/titanium carbide nanorod array/titanium (graphene/TiC nanorod array) wires were fabricated using a direct current arc plasma jet chemical vapor deposition (DC arc plasma jet CVD) method. The graphene/TiC nanorod arrays were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction spectroscopy. The TiO 2 nanotube array was reduced to the TiC nanorod array, and using those TiC nanorods as nucleation sites, the vertical graphene layer was formed on the TiC nanorod surface. The multi-target response mechanisms of the graphene/TiC nanorod array were investigated for ascorbic acid (AA), dopamine (DA), uric acid (UA), and hydrochlorothiazide (HCTZ). The vertically stacked graphene sheets facilitated the electron transfer and reactant transport with a unique porous surface, high surface area, and high electron transport network of CVD graphene sheets. The TiC nanorod array facilitated the electron transfer and firmly held the graphene layer. Thus, the graphene/TiC nanorod arrays could simultaneously respond to trace biomarkers and antihypertensive drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

Layer-by-layer 3-dimensional nanofiber tissue scaffold with controlled gap by electrospinning

NASA Astrophysics Data System (ADS)

Lin, Sai-Jun; Xue, Ya-Ping; Chang, Guoqing; Han, Qiao-Ling; Chen, Li-Fang; Jia, Yan-Bo; Zheng, Yu-Guo

2018-02-01

The development of three-dimensional (3D) nanofiber structures by electrospinning has drawn considerable attention in the field of tissue scaffolds. However, the generation of two dimensional mats using the conventional method limits electrospinning, the electrical charging of polymer liquids, as a means of nanofiber fabrication. In this study, we established a facile method of fabrication of layer-by-layer 3D polycaprolactone (PCL) nanofiber structures by utilizing a booklet collector with controlled morphology. Meanwhile, we explore the application of the manufactured 3D architectures in the field of tissue scaffolds. The approximately 20 μm layer-to-layer distance enhanced the ability of cells to migrate freely into tissues and induce cells in an ordered arrangement.

Core-to-core uniformity improvement in multi-core fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Lindley, Emma; Min, Seong-Sik; Leon-Saval, Sergio; Cvetojevic, Nick; Jovanovic, Nemanja; Bland-Hawthorn, Joss; Lawrence, Jon; Gris-Sanchez, Itandehui; Birks, Tim; Haynes, Roger; Haynes, Dionne

2014-07-01

Multi-core fiber Bragg gratings (MCFBGs) will be a valuable tool not only in communications but also various astronomical, sensing and industry applications. In this paper we address some of the technical challenges of fabricating effective multi-core gratings by simulating improvements to the writing method. These methods allow a system designed for inscribing single-core fibers to cope with MCFBG fabrication with only minor, passive changes to the writing process. Using a capillary tube that was polished on one side, the field entering the fiber was flattened which improved the coverage and uniformity of all cores.

WE-E-18A-01: Large Area Avalanche Amorphous Selenium Sensors for Low Dose X-Ray Imaging

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

Scheuermann, J; Goldan, A; Zhao, W

2014-06-15

Purpose: A large area indirect flat panel imager (FPI) with avalanche gain is being developed to achieve x-ray quantum noise limited low dose imaging. It uses a thin optical sensing layer of amorphous selenium (a-Se), known as High-Gain Avalanche Rushing Photoconductor (HARP), to detect optical photons generated from a high resolution x-ray scintillator. We will report initial results in the fabrication of a solid-state HARP structure suitable for a large area FPI. Our objective is to establish the blocking layer structures and defect suppression mechanisms that provide stable and uniform avalanche gain. Methods: Samples were fabricated as follows: (1) ITOmore » signal electrode. (2) Electron blocking layer. (3) A 15 micron layer of intrinsic a-Se. (4) Transparent hole blocking layer. (5) Multiple semitransparent bias electrodes to investigate avalanche gain uniformity over a large area. The sample was exposed to 50ps optical excitation pulses through the bias electrode. Transient time of flight (TOF) and integrated charge was measured. A charge transport simulation was developed to investigate the effects of varying blocking layer charge carrier mobility on defect suppression, avalanche gain and temporal performance. Results: Avalanche gain of ∼200 was achieved experimentally with our multi-layer HARP samples. Simulations using the experimental sensor structure produced the same magnitude of gain as a function of electric field. The simulation predicted that the high dark current at a point defect can be reduced by two orders of magnitude by blocking layer optimization which can prevent irreversible damage while normal operation remained unaffected. Conclusion: We presented the first solid state HARP structure directly scalable to a large area FPI. We have shown reproducible and uniform avalanche gain of 200. By reducing mobility of the blocking layers we can suppress defects and maintain stable avalanche. Future work will optimize the blocking layers to prevent lag and ghosting.« less

Comparative Study of Impedance Eduction Methods, Part 2: NASA Tests and Methodology

NASA Technical Reports Server (NTRS)

Jones, Michael G.; Watson, Willie R.; Howerton, Brian M.; Busse-Gerstengarbe, Stefan

2013-01-01

A number of methods have been developed at NASA Langley Research Center for eduction of the acoustic impedance of sound-absorbing liners mounted in the wall of a flow duct. This investigation uses methods based on the Pridmore-Brown and convected Helmholtz equations to study the acoustic behavior of a single-layer, conventional liner fabricated by the German Aerospace Center and tested in the NASA Langley Grazing Flow Impedance Tube. Two key assumptions are explored in this portion of the investigation. First, a comparison of results achieved with uniform-flow and shear-flow impedance eduction methods is considered. Also, an approach based on the Prony method is used to extend these methods from single-mode to multi-mode implementations. Finally, a detailed investigation into the effects of harmonic distortion on the educed impedance is performed, and the results are used to develop guidelines regarding acceptable levels of harmonic distortion

Dynamic MEMS devices for multi-axial fatigue and elastic modulus measurement

NASA Astrophysics Data System (ADS)

White, Carolyn D.; Xu, Rui; Sun, Xiaotian; Komvopoulos, Kyriakos

2003-01-01

For reliable MEMS device fabrication and operation, there is a continued demand for precise characterization of materials at the micron scale. This paper presents a novel material characterization device for fatigue lifetime testing. The fatigue specimen is subjected to multi-axial loading, which is typical of most MEMS devices. Polycrystalline silicon (polysilicon) fatigue devices were fabricated using the MUMPS process with a three layer mask process ground plane, anchor, and structural layer of polysilicon. A fatigue device consists of two or three beams, attached to a rotating ring and anchored to the substrate on each end. In order to generate a sufficiently large stress, the fatigue devices were tested in resonance to produce a von Mises equivalent stress as high as 1 GPa, which is in the fracture strength range reported for polysilicon. A further increase of the stress in the beam specimens was obtained by introducing a notch with a focused ion beam. The notch resulted into a stress concentration factor of about 3.8, thereby producing maximum von Mises equivalent stress in the range of 1 through 4 GPa. This study provides insight into multi-axial fatigue testing under typical MEMS conditions and additional information about micron-scale polysilicon mechanical behavior, which is the current basic building material for MEMS devices.

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.

Simplified Abrasion Test Methodology for Candidate EVA Glove Lay-Ups

NASA Technical Reports Server (NTRS)

Rabel, Emily; Aitchison, Lindsay

2015-01-01

During the Apollo Program, space suit outer-layer fabrics were badly abraded after performing just a few extravehicular activities (EVAs). For example, the Apollo 12 commander reported abrasive wear on the boots that penetrated the outer-layer fabric into the thermal protection layers after less than 8 hrs of surface operations. Current plans for the exploration planetary space suits require the space suits to support hundreds of hours of EVA on a lunar or Martian surface, creating a challenge for space suit designers to utilize materials advances made over the last 40 years and improve on the space suit fabrics used in the Apollo Program. Over the past 25 years the NASA Johnson Space Center Crew and Thermal Systems Division has focused on tumble testing as means of simulating wear on the outer layer of the space suit fabric. Most recently, in 2009, testing was performed on 4 different candidate outer layers to gather baseline data for future use in design of planetary space suit outer layers. In support of the High Performance EVA Glove Element of the Next Generation Life Support Project, testing a new configuration was recently attempted in which require 10% of the fabric per replicate of that need in 2009. The smaller fabric samples allowed for reduced per sample cost and flexibility to test small samples from manufacturers without the overhead to have a production run completed. Data collected from this iteration was compared to that taken in 2009 to validate the new test method. In addition the method also evaluated the fabrics and fabric layups used in a prototype thermal micrometeoroid garment (TMG) developed for EVA gloves under the NASA High Performance EVA Glove Project. This paper provides a review of previous abrasion studies on space suit fabrics, details methodologies used for abrasion testing in this particular study, results of the validation study, and results of the TMG testing.

Increasing component functionality via multi-process additive manufacturing

NASA Astrophysics Data System (ADS)

Coronel, Jose L.; Fehr, Katherine H.; Kelly, Dominic D.; Espalin, David; Wicker, Ryan B.

2017-05-01

Additively manufactured components, although extensively customizable, are often limited in functionality. Multi-process additive manufacturing (AM) grants the ability to increase the functionality of components via subtractive manufacturing, wire embedding, foil embedding and pick and place. These processes are scalable to include several platforms ranging from desktop to large area printers. The Multi3D System is highlighted, possessing the capability to perform the above mentioned processes, all while transferring a fabricated component with a robotic arm. Work was conducted to fabricate a patent inspired, printed missile seeker. The seeker demonstrated the advantage of multi-process AM via introduction of the pick and place process. Wire embedding was also explored, with the successful interconnect of two layers of embedded wires in different planes. A final demonstration of a printed contour bracket, served to show the reduction of surface roughness on a printed part is 87.5% when subtractive manufacturing is implemented in tandem with AM. Functionality of the components on all the cases was improved. Results included optical components embedded within the printed housing, wires embedded with interconnection, and reduced surface roughness. These results highlight the improved functionality of components through multi-process AM, specifically through work conducted with the Multi3D System.

A Study of Dip-Coatable, High-Capacitance Ion Gel Dielectrics for 3D EWOD Device Fabrication

PubMed Central

Clement, Carlos E.; Jiang, Dongyue; Thio, Si Kuan; Park, Sung-Yong

2017-01-01

We present a dip-coatable, high-capacitance ion gel dielectric for scalable fabrication of three-dimensional (3D) electrowetting-on-dielectric (EWOD) devices such as an n × n liquid prism array. Due to the formation of a nanometer-thick electric double layer (EDL) capacitor, an ion gel dielectric offers two to three orders higher specific capacitance (c ≈ 10 μF/cm2) than that of conventional dielectrics such as SiO2. However, the previous spin-coating method used for gel layer deposition poses several issues for 3D EWOD device fabrication, particularly when assembling multiple modules. Not only does the spin-coating process require multiple repetitions per module, but the ion gel layer also comes in risks of damage or contamination due to handling errors caused during assembly. In addition, it was observed that the chemical formulation previously used for the spin-coating method causes the surface defects on the dip-coated gel layers and thus leads to poor EWOD performance. In this paper, we alternatively propose a dip-coating method with modified gel solutions to obtain defect-free, functional ion gel layers without the issues arising from the spin-coating method for 3D device fabrication. A dip-coating approach offers a single-step coating solution with the benefits of simplicity, scalability, and high throughput for deposition of high-capacitance gel layers on non-planar EWOD devices. An ion gel solution was prepared by combining the [EMIM][TFSI] ionic liquid and the [P(VDF-HFP)] copolymer at various wt % ratios in acetone solvent. Experimental studies were conducted to fully understand the effects of chemical composition ratios in the gel solution and how varying thicknesses of ion gel and Teflon layers affects EWOD performance. The effectiveness and potentiality of dip-coatable gel layers for 3D EWOD devices have been demonstrated through fabricating 5 × 1 arrayed liquid prisms using a single-step dip-coating method. Each prism module has been individually controlled to achieve spatial beam steering without the need for bulky mechanical moving parts. PMID:28772400

A Study of Dip-Coatable, High-Capacitance Ion Gel Dielectrics for 3D EWOD Device Fabrication.

PubMed

Clement, Carlos E; Jiang, Dongyue; Thio, Si Kuan; Park, Sung-Yong

2017-01-05

We present a dip-coatable, high-capacitance ion gel dielectric for scalable fabrication of three-dimensional (3D) electrowetting-on-dielectric (EWOD) devices such as an n × n liquid prism array. Due to the formation of a nanometer-thick electric double layer (EDL) capacitor, an ion gel dielectric offers two to three orders higher specific capacitance ( c ≈ 10 μF/cm²) than that of conventional dielectrics such as SiO₂. However, the previous spin-coating method used for gel layer deposition poses several issues for 3D EWOD device fabrication, particularly when assembling multiple modules. Not only does the spin-coating process require multiple repetitions per module, but the ion gel layer also comes in risks of damage or contamination due to handling errors caused during assembly. In addition, it was observed that the chemical formulation previously used for the spin-coating method causes the surface defects on the dip-coated gel layers and thus leads to poor EWOD performance. In this paper, we alternatively propose a dip-coating method with modified gel solutions to obtain defect-free, functional ion gel layers without the issues arising from the spin-coating method for 3D device fabrication. A dip-coating approach offers a single-step coating solution with the benefits of simplicity, scalability, and high throughput for deposition of high-capacitance gel layers on non-planar EWOD devices. An ion gel solution was prepared by combining the [EMIM][TFSI] ionic liquid and the [P(VDF-HFP)] copolymer at various wt % ratios in acetone solvent. Experimental studies were conducted to fully understand the effects of chemical composition ratios in the gel solution and how varying thicknesses of ion gel and Teflon layers affects EWOD performance. The effectiveness and potentiality of dip-coatable gel layers for 3D EWOD devices have been demonstrated through fabricating 5 × 1 arrayed liquid prisms using a single-step dip-coating method. Each prism module has been individually controlled to achieve spatial beam steering without the need for bulky mechanical moving parts.

Microscope Cells Containing Multiple Micromachined Wells

NASA Technical Reports Server (NTRS)

Turner, Walter; Skupinski, Robert

2003-01-01

Tech Briefs, May 2003 19 Manufacturing Microscope Cells Containing Multiple Micromachined Wells The cost per cell has been reduced substantially. John H. Glenn Research Center, Cleveland, Ohio An improved design for multiple-well microscope cells and an associated improved method of fabricating them have been devised. [As used here, "well" denotes a cavity that has a volume of about 1 or 2 L and that is used to hold a sample for examination under a microscope. As used here, "cell" denotes a laminate, based on a standard 1- by 3-in. (2.54- by 7.62-cm) microscope slide, that comprises (1) the slide as the lower layer, (2) an intermediate layer that contains holes that serve as the wells, and (3) a top layer that either consists of, or is similar to, a standard microscope-slide cover slip.] The improved design and method of fabrication make it possible to increase (relative to a prior design and method of fabrication) the number of wells per cell while reducing the fabrication loss and reducing the cost per cell to about one-tenth of the prior value. In the prior design and method, the slide, well, and cover-slip layers were made from silicate glass. The fabrication of each cell was a labor-intensive process that included precise cutting and grinding of the glass components, fusing of the glass components, and then more grinding and polishing to obtain desired dimensions. Cells of the prior design were expensive and fragile, the rate of loss in fabrication was high, and the nature of the glass made it difficult to increase the number of cells per well. Efforts to execute alternative prior designs in plastic have not yielded satisfactory results because, for typical applications, plastics are not sufficiently thermally or chemically stable, not sufficiently optically clear, and/or not hard enough to resist scratching. The figure depicts a cell of the present improved type. The slide and cover-slip layers are made of a low-thermal-expansion glass (Pyrex(TradeMark) or equivalent) and the intermediate (well layer) is made of SiO2 - a combination of materials that results in a laminate stronger than one made from layers of silicate glass. Before the layers are assembled into the laminate, the SiO2 layer is micromachined to form the wells plus shallow grooves that, when subsequently covered with the cover slip, become capillary channels that are used to fill the wells with samples. The micromachining is accomplished by use of the same patterning and etching techniques used to fabricate microelectromechanical systems (MEMS).

Fabrication of Cu2SnS3 thin films by ethanol-ammonium solution process by doctor-blade technique

NASA Astrophysics Data System (ADS)

Wang, Yaguang; Li, Jianmin; Xue, Cong; Zhang, Yan; Jiang, Guoshun; Liu, Weifeng; Zhu, Changfei

2017-11-01

In the present study, a low-cost and simple method is applied to fabricate Cu2SnS3 (CTS) thin films. Namely CTS thin films are prepared by a doctor-blade method with a slurry dissolving the Cu2O and SnS powders obtained from CBD reaction solution into ethanol-ammonium solvents. Series of characterization methods including XRD, Raman spectra, SEM and UV-Vis analyses are introduced to investigate the phase structure, morphology and optical properties of CTS thin films. As a result, monoclinic CTS films have been obtained with the disappearance of binary phases CuS and SnS2 while increasing the annealing temperature and time, high quality monoclinic CTS thin films consisting of compact and large grains have been successfully prepared by this ethanol-ammonium method. Moreover, the secondary phase Cu2Sn3S7 is also observed during the annealing process. In addition, the post-annealed CTS film with a band-gap about 0.89 eV shows excellent absorbance between 400 and 1200 nm, which is proper for the bottom layer in multi-junction thin film solar cells.[Figure not available: see fulltext.

An inference method from multi-layered structure of biomedical data.

PubMed

Kim, Myungjun; Nam, Yonghyun; Shin, Hyunjung

2017-05-18

Biological system is a multi-layered structure of omics with genome, epigenome, transcriptome, metabolome, proteome, etc., and can be further stretched to clinical/medical layers such as diseasome, drugs, and symptoms. One advantage of omics is that we can figure out an unknown component or its trait by inferring from known omics components. The component can be inferred by the ones in the same level of omics or the ones in different levels. To implement the inference process, an algorithm that can be applied to the multi-layered complex system is required. In this study, we develop a semi-supervised learning algorithm that can be applied to the multi-layered complex system. In order to verify the validity of the inference, it was applied to the prediction problem of disease co-occurrence with a two-layered network composed of symptom-layer and disease-layer. The symptom-disease layered network obtained a fairly high value of AUC, 0.74, which is regarded as noticeable improvement when comparing 0.59 AUC of single-layered disease network. If further stretched to whole layered structure of omics, the proposed method is expected to produce more promising results. This research has novelty in that it is a new integrative algorithm that incorporates the vertical structure of omics data, on contrary to other existing methods that integrate the data in parallel fashion. The results can provide enhanced guideline for disease co-occurrence prediction, thereby serve as a valuable tool for inference process of multi-layered biological system.

Metallized Products

NASA Technical Reports Server (NTRS)

1980-01-01

Since the early 1960's, virtually all NASA spacecraft have used metallized films for a variety of purposes, principally thermal radiation insulation. King Seeley manufactures a broad line of industrial and consumer oriented metallized film, fabric, paper and foam in single layer sheets and multi-layer laminates. A few examples, commercialized by MPI Outdoor Safety Products, are the three ounce Thermos Emergency Blanket which reflects and retains up to 80 percent of the user's body heat helping prevent post accident shock or keeping a person warm for hours under emergency cold weather conditions.

Multi-Dimensional Damage Detection for Surfaces and Structures

NASA Technical Reports Server (NTRS)

Williams, Martha; Lewis, Mark; Roberson, Luke; Medelius, Pedro; Gibson, Tracy; Parks, Steen; Snyder, Sarah

2013-01-01

Current designs for inflatable or semi-rigidized structures for habitats and space applications use a multiple-layer construction, alternating thin layers with thicker, stronger layers, which produces a layered composite structure that is much better at resisting damage. Even though such composite structures or layered systems are robust, they can still be susceptible to penetration damage. The ability to detect damage to surfaces of inflatable or semi-rigid habitat structures is of great interest to NASA. Damage caused by impacts of foreign objects such as micrometeorites can rupture the shell of these structures, causing loss of critical hardware and/or the life of the crew. While not all impacts will have a catastrophic result, it will be very important to identify and locate areas of the exterior shell that have been damaged by impacts so that repairs (or other provisions) can be made to reduce the probability of shell wall rupture. This disclosure describes a system that will provide real-time data regarding the health of the inflatable shell or rigidized structures, and information related to the location and depth of impact damage. The innovation described here is a method of determining the size, location, and direction of damage in a multilayered structure. In the multi-dimensional damage detection system, layers of two-dimensional thin film detection layers are used to form a layered composite, with non-detection layers separating the detection layers. The non-detection layers may be either thicker or thinner than the detection layers. The thin-film damage detection layers are thin films of materials with a conductive grid or striped pattern. The conductive pattern may be applied by several methods, including printing, plating, sputtering, photolithography, and etching, and can include as many detection layers that are necessary for the structure construction or to afford the detection detail level required. The damage is detected using a detector or sensory system, which may include a time domain reflectometer, resistivity monitoring hardware, or other resistance-based systems. To begin, a layered composite consisting of thin-film damage detection layers separated by non-damage detection layers is fabricated. The damage detection layers are attached to a detector that provides details regarding the physical health of each detection layer individually. If damage occurs to any of the detection layers, a change in the electrical properties of the detection layers damaged occurs, and a response is generated. Real-time analysis of these responses will provide details regarding the depth, location, and size estimation of the damage. Multiple damages can be detected, and the extent (depth) of the damage can be used to generate prognostic information related to the expected lifetime of the layered composite system. The detection system can be fabricated very easily using off-the-shelf equipment, and the detection algorithms can be written and updated (as needed) to provide the level of detail needed based on the system being monitored. Connecting to the thin film detection layers is very easy as well. The truly unique feature of the system is its flexibility; the system can be designed to gather as much (or as little) information as the end user feels necessary. Individual detection layers can be turned on or off as necessary, and algorithms can be used to optimize performance. The system can be used to generate both diagnostic and prognostic information related to the health of layer composite structures, which will be essential if such systems are utilized for space exploration. The technology is also applicable to other in-situ health monitoring systems for structure integrity.

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

Das, Saptarshi; Bera, Mrinal K.; Roelofs, Andreas K

A method of forming a TMDC monolayer comprises providing a multi-layer transition metal dichalcogenide (TMDC) film. The multi-layer TMDC film comprises a plurality of layers of the TMDC. The multi-layer TMDC film is positioned on a conducting substrate. The conducting substrate is contacted with an electrolyte solution. A predetermined electrode potential is applied on the conducting substrate and the TMDC monolayer for a predetermined time. A portion of the plurality of layers of the TMDC included in the multi-layer TMDC film is removed by application of the predetermined electrode potential, thereby leaving a TMDC monolayer film positioned on the conductingmore » substrate.« less

Fabrication of nanoporous membranes for tuning microbial interactions and biochemical reactions

DOE PAGES

Shankles, Peter G.; Timm, Andrea C.; Doktycz, Mitchel J.; ...

2015-10-21

Here we describe how new strategies for combining conventional photo- and soft- lithographic techniques with high-resolution patterning and etching strategies are needed in order to produce multi-scale fluidic platforms that address the full range of functional scales seen in complex biological and chemical systems. The smallest resolution required for an application often dictates the fabrication method used. Micromachining and micro-powder blasting yield higher throughput, but lack the resolution needed to fully address biological and chemical systems at the cellular and molecular scales. In contrast, techniques such as electron beam lithography or nanoimprinting allow nanoscale resolution, but are traditionally considered costlymore » and slow. Other techniques such as photolithography or soft lithography have characteristics between these extremes. Combining these techniques to fabricate multi-scale or hybrid fluidics allows fundamental biological and chemical questions can be answered. In this study, a combination of photolithography and electron beam lithography are used to produce two multi-scale fluidic devices that incorporate porous membranes into complex fluidic networks to control the flow of energy, information, and materials in chemical form. In the first device, materials and energy were used to support chemical reactions. A nanoporous membrane fabricated with e-beam lithography separates two parallel, serpentine channels. Photolithography was used to write microfluidic channels around the membrane. The pores were written at 150nm and reduced in size with silicon dioxide deposition from plasma enhanced chemical vapor deposition (PECVD) and atomic layer deposition (ALD). Using this method, the molecular weight cutoff (MWCO) of the membrane can be adapted to the system of interest. In the second approach, photolithography was used to fabricate 200nm thin pores. The pores confined microbes and allowed energy replenishment from a media perfusion channel. The same device can be used for study of intercellular communication via the secretion and uptake of signal molecules. Pore size was tested with 750nm fluorescent polystyrene beads and fluorescein dye. The 200nm PDMS pores were shown to be robust enough to hold 750nm beads while under pressure, but allow fluorescein to diffuse across the barrier. Further testing showed that extended culture of bacteria within the chambers was possible. Finally, these two examples show how lithographically defined porous membranes can be adapted to two unique situations and used to tune the flow of chemical energy, materials, and information within a microfluidic network.« less

Controlling successive ionic layer absorption and reaction cycles to optimize silver nanoparticle-induced localized surface plasmon resonance effects on the paper strip

NASA Astrophysics Data System (ADS)

Lee, Jae-Chul; Kim, Wansun; Park, Hun-Kuk; Choi, Samjin

2017-03-01

This study investigates why a silver nanoparticle (SNP)-induced surface-enhanced Raman scattering (SERS) paper chip fabricated at low successive ionic layer absorption and reaction (SILAR) cycles leads to a high SERS enhancement factor (7 × 108) with an inferior nanostructure and without generating a hot spot effect. The multi-layered structure of SNPs on cellulose fibers, verified by magnified scanning electron microscopy (SEM) and analyzed by a computational simulation method, was hypothesized as the reason. The pattern of simulated local electric field distribution with respect to the number of SILAR cycles showed good agreement with the experimental Raman intensity, regardless of the wavelength of the excitation laser sources. The simulated enhancement factor at the 785-nm excitation laser source (2.8 × 109) was 2.5 times greater than the experimental enhancement factor (1.1 × 109). A 532-nm excitation laser source exhibited the highest maximum local electric field intensity (1.9 × 1011), particularly at the interparticle gap called a hot spot. The short wavelength led to a strong electric field intensity caused by strong electromagnetic coupling arising from the SNP-induced local surface plasmon resonance (LSPR) effects through high excitation energy. These findings suggest that our paper-based SILAR-fabricated SNP-induced LSPR model is valid for understanding SNP-induced LSPR effects.

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.

Color tunable monolithic InGaN/GaN LED having a multi-junction structure.

PubMed

Kong, Duk-Jo; Kang, Chang-Mo; Lee, Jun-Yeob; Kim, James; Lee, Dong-Seon

2016-03-21

In this study, we have fabricated a blue-green color-tunable monolithic InGaN/GaN LED having a multi-junction structure with three terminals. The device has an n-p-n structure consisting of a green and a blue active region, i.e., an n-GaN / blue-MQW / p-GaN / green-MQW / n-GaN / Al₂O₃ structure with three terminals for independently controlling the two active regions. To realize this LED structure, a typical LED consisting of layers of n-GaN, blue MQW, and p-GaN is regrown on a conventional green LED by using a metal organic chemical vapor deposition (MOCVD) method. We explain detailed mechanisms of three operation modes which are the green, blue, and cyan mode. Moreover, we discuss optical properties of the device.

Systems and Methods for Fabricating Carbon Nanotube-Based Vacuum Electronic Devices

NASA Technical Reports Server (NTRS)

Manohara, Harish (Inventor); Toda, Risaku (Inventor); Del Castillo, Linda Y. (Inventor); Murthy, Rakesh (Inventor)

2015-01-01

Systems and methods in accordance with embodiments of the invention proficiently produce carbon nanotube-based vacuum electronic devices. In one embodiment a method of fabricating a carbon nanotube-based vacuum electronic device includes: growing carbon nanotubes onto a substrate to form a cathode; assembling a stack that includes the cathode, an anode, and a first layer that includes an alignment slot; disposing a microsphere partially into the alignment slot during the assembling of the stack such that the microsphere protrudes from the alignment slot and can thereby separate the first layer from an adjacent layer; and encasing the stack in a vacuum sealed container.

Amperometric Choline Biosensor Fabricated through Electrostatic Assembly of Bienzyme/Polyelectrolyte Hybrid Layers on Carbon Nanotubes

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

Wang, Jun; Liu, Guodong; Lin, Yuehe

2006-03-01

We report a flow injection amperometric choline biosensors based on the electrostatic assembly of an enzyme of choline oxidase (ChO) and a bi-enzyme of ChO and horseradish peroxidase (HRP) onto multi-wall carbon nanotubes (MWCNT) modified glassy carbon (GC) electrodes. These choline biosensors were fabricated by immobilization of enzymes on the negatively charged MWCNT surface through alternatively assembling a cationic polydiallydiimethylammonium chloride (PDDA) layer and an enzyme layer. Using this layer-by-layer assembling approach, bioactive nanocomposite film of a PDDA/ChO/PDDA/HRP/PDDA/CNT (ChO/HRP/CNT) and a PDDA/ChO/PDDA/ CNT (ChO/ CNT) were fabricated on GC surface, respectively. Owning to the electrocatalytic effect of carbon nanotubes, themore » measurement of faradic responses resulting from enzymatic reactions has been realized at low potential with acceptable sensitivity. It is found the ChO/HRP/CNT biosensor is more sensitive than the ChO/CNT one. Experimental parameters affecting the sensitivity of biosensors, e.g. applied potential, flow rate, etc. were optimized and potential interference was examined. The response time for this choline biosensor is fast (less than a few seconds). The linear range of detection for the choline biosensor is from 5 x 10-5 to 5 x 10-3 M and the detection limit is determined to be about 1.0 x 10-5 M.« less

Facile Fabrication of Composite Membranes with Dual Thermo- and pH-Responsive Characteristics.

PubMed

Ma, Bing; Ju, Xiao-Jie; Luo, Feng; Liu, Yu-Qiong; Wang, Yuan; Liu, Zhuang; Wang, Wei; Xie, Rui; Chu, Liang-Yin

2017-04-26

Facile fabrication of novel functional membranes with excellent dual thermo- and pH-responsive characteristics has been achieved by simply designing dual-layer composite membranes. pH-Responsive poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymers and polystyrene blended with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) nanogels are respectively used to construct the top layer and bottom layer of composite membranes. The stretching/coiling conformation changes of the P4VP chains around the pK a (∼3.5-4.5) provide the composite membranes with extraordinary pH-responsive characteristics, and the volume phase transitions of PNIPAM nanogels at the pore/matrix interfaces in the bottom layer around the volume phase transition temperature (VPTT, ∼33 °C) provide the composite membranes with great thermoresponsive characteristics. The microstructures, permeability performances, and dual stimuli-responsive characteristics can be well tuned by adjusting the content of PNIPAM nanogels and the thickness of the PS-b-P4VP top layer. The water fluxes of the composite membranes can be changed in order of magnitude by changing the environment temperature and pH, and the dual thermo- and pH-responsive permeation performances of the composite membranes are satisfactorily reversible and reproducible. The membrane fabrication strategy in this work provides valuable guidance for further development of dual stimuli-responsive membranes or even multi stimuli-responsive membranes.

Multijunction photovoltaic device and fabrication method

DOEpatents

Arya, Rajeewa R.; Catalano, Anthony W.

1993-09-21

A multijunction photovoltaic device includes first and second amorphous silicon PIN photovoltaic cells in a stacked arrangement. An interface layer, composed of a doped silicon compound, is disposed between the two cells and has a lower bandgap than the respective n- and p-type adjacent layers of the first and second cells. The interface layer forms an ohmic contact with the one or the adjacent cell layers of the same conductivity type, and a tunnel junction with the other of the adjacent cell layers. The disclosed device is fabricated by a glow discharge process.

Flexible Multi-Shock Shield

NASA Technical Reports Server (NTRS)

Christiansen, Eric L. (Inventor); Crews, Jeanne L. (Inventor)

2005-01-01

Flexible multi-shock shield system and method are disclosed for defending against hypervelocity particles. The flexible multi-shock shield system and method may include a number of flexible bumpers or shield layers spaced apart by one or more resilient support layers, all of which may be encapsulated in a protective cover. Fasteners associated with the protective cover allow the flexible multi-shock shield to be secured to the surface of a structure to be protected.

Teflon/SiO2 Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process

PubMed Central

Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Hung, Bohr-Ran

2015-01-01

This study proposes a two-photomask process for fabricating amorphous indium–gallium–zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO2 combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO2 deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity. PMID:28788026

Controllable liquid colour-changing lenses with microfluidic channels for vision protection, camouflage and optical filtering based on soft lithography fabrication.

PubMed

Zhang, Min; Li, Songjing

2016-01-01

In this work, liquid colour-changing lenses for vision protection, camouflage and optical filtering are developed by circulating colour liquids through microfluidic channels on the lenses manually. Soft lithography technology is applied to fabricate the silicone liquid colour-changing layers with microfluidic channels on the lenses instead of mechanical machining. To increase the hardness and abrasion resistance of the silicone colour-changing layers on the lenses, proper fabrication parameters such as 6:1 (mass ration) mixing proportion and 100 °C curing temperature for 2 h are approved for better soft lithography process of the lenses. Meanwhile, a new surface treatment for the irreversible bonding of silicone colour-changing layer with optical resin (CR39) substrate lens by using 5 % (volume ratio) 3-Aminopropyltriethoxysilane solution is proposed. Vision protection, camouflage and optical filtering functions of the lenses are investigated with different designs of the channels and multi-layer structures. Each application can not only well achieve their functional demands, but also shows the advantages of functional flexibility, rapid prototyping and good controllability compared with traditional ways. Besides optometry, some other designs and applications of the lenses are proposed for potential utility in the future.

An improved multi-exposure approach for high quality holographic femtosecond laser patterning

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

Zhang, Chenchu; Hu, Yanlei, E-mail: huyl@ustc.edu.cn, E-mail: jwl@ustc.edu.cn; Li, Jiawen, E-mail: huyl@ustc.edu.cn, E-mail: jwl@ustc.edu.cn

High efficiency two photon polymerization through single exposure via spatial light modulator (SLM) has been used to decrease the fabrication time and rapidly realize various micro/nanostructures, but the surface quality remains a big problem due to the speckle noise of optical intensity distribution at the defocused plane. Here, a multi-exposure approach which used tens of computer generate holograms successively loaded on SLM is presented to significantly improve the optical uniformity without losing efficiency. By applying multi-exposure, we found that the uniformity at the defocused plane was increased from ∼0.02 to ∼0.6 according to our simulation. The fabricated two series ofmore » letters “HELLO” and “USTC” under single-and multi-exposure in our experiment also verified that the surface quality was greatly improved. Moreover, by this method, several kinds of beam splitters with high quality, e.g., 2 × 2, 5 × 5 Daman, and complex nonseperate 5 × 5, gratings were fabricated with both of high quality and short time (<1 min, 95% time-saving). This multi-exposure SLM-two-photon polymerization method showed the promising prospect in rapidly fabricating and integrating various binary optical devices and their systems.« less

Constructing bio-layer of heparin and type IV collagen on titanium surface for improving its endothelialization and blood compatibility.

PubMed

Zhang, Kun; Chen, Jun-ying; Qin, Wei; Li, Jing-an; Guan, Fang-xia; Huang, Nan

2016-04-01

The modification of cardiovascular stent surface for a better micro-environment has gradually changed to multi-molecule, multi-functional designation. In this study, heparin (Hep) and type IV collagen (IVCol) were used as the functional molecule to construct a bifunctional micro-environment of anticoagulation and promoting endothelialization on titanium (Ti). The surface characterization results (AFM, Alcian Blue 8GX Staining and fluorescence staining of IVCol) indicated that the bio-layer of Hep and IVCol were successfully fabricated on the Ti surface through electrostatic self-assembly. The APTT and platelet adhesion test demonstrated that the bionic layer possessed better blood compatibility compared with Ti surface. The adhesion, proliferation, migration and apoptosis tests of endothelial cells proved that the Hep/IVCol layer was able to enhance the endothelialization of the Ti surface. The in vivo animal implantation results manifested that the bionic surface could encourage new endothelialization. This work provides an important reference for the construction of multifunction micro-environment on the cardiovascular scaffold surface.

Multi-spectral Metasurface for Different Functional Control of Reflection Waves.

PubMed

Huang, Cheng; Pan, Wenbo; Ma, Xiaoliang; Luo, Xiangang

2016-03-22

Metasurface have recently generated much interest due to its strong manipulation of electromagnetic wave and its easy fabrication compared to bulky metamaterial. Here, we propose the design of a multi-spectral metasurface that can achieve beam deflection and broadband diffusion simultaneously at two different frequency bands. The metasurface is composed of two-layered metallic patterns backed by a metallic ground plane. The top-layer metasurface utilizes the cross-line structures with two different dimensions for producing 0 and π reflection phase response, while the bottom-layer metasurface is realized by a topological morphing of the I-shaped patterns for creating the gradient phase distribution. The whole metasurface is demonstrated to independently control the reflected waves to realize different functions at two bands when illuminated by a normal linear-polarized wave. Both simulation and experimental results show that the beam deflection is achieved at K-band with broadband diffusion at X-Ku band.

Multi-spectral Metasurface for Different Functional Control of Reflection Waves

PubMed Central

Huang, Cheng; Pan, Wenbo; Ma, Xiaoliang; Luo, Xiangang

2016-01-01

Metasurface have recently generated much interest due to its strong manipulation of electromagnetic wave and its easy fabrication compared to bulky metamaterial. Here, we propose the design of a multi-spectral metasurface that can achieve beam deflection and broadband diffusion simultaneously at two different frequency bands. The metasurface is composed of two-layered metallic patterns backed by a metallic ground plane. The top-layer metasurface utilizes the cross-line structures with two different dimensions for producing 0 and π reflection phase response, while the bottom-layer metasurface is realized by a topological morphing of the I-shaped patterns for creating the gradient phase distribution. The whole metasurface is demonstrated to independently control the reflected waves to realize different functions at two bands when illuminated by a normal linear-polarized wave. Both simulation and experimental results show that the beam deflection is achieved at K-band with broadband diffusion at X-Ku band. PMID:27001206

Method for fabricating an interconnected array of semiconductor devices

DOEpatents

Grimmer, Derrick P.; Paulson, Kenneth R.; Gilbert, James R.

1989-10-10

Semiconductor layer and conductive layer formed on a flexible substrate, divided into individual devices and interconnected with one another in series by interconnection layers and penetrating terminals.

A Theoretical Model for Predicting Residual Stress Generation in Fabrication Process of Double-Ceramic-Layer Thermal Barrier Coating System.

PubMed

Song, Yan; Wu, Weijie; Xie, Feng; Liu, Yilun; Wang, Tiejun

2017-01-01

Residual stress arisen in fabrication process of Double-Ceramic-Layer Thermal Barrier Coating System (DCL-TBCs) has a significant effect on its quality and reliability. In this work, based on the practical fabrication process of DCL-TBCs and the force and moment equilibrium, a theoretical model was proposed at first to predict residual stress generation in its fabrication process, in which the temperature dependent material properties of DCL-TBCs were incorporated. Then, a Finite Element method (FEM) has been carried out to verify our theoretical model. Afterwards, some important geometric parameters for DCL-TBCs, such as the thickness ratio of stabilized Zirconia (YSZ, ZrO2-8%Y2O3) layer to Lanthanum Zirconate (LZ, La2Zr2O7) layer, which is adjustable in a wide range in the fabrication process, have a remarkable effect on its performance, therefore, the effect of this thickness ratio on residual stress generation in the fabrication process of DCL-TBCs has been systematically studied. In addition, some thermal spray treatment, such as the pre-heating treatment, its effect on residual stress generation has also been studied in this work. It is found that, the final residual stress mainly comes from the cooling down process in the fabrication of DCL-TBCs. Increasing the pre-heating temperature can obviously decrease the magnitude of residual stresses in LZ layer, YSZ layer and substrate. With the increase of the thickness ratio of YSZ layer to LZ layer, magnitudes of residual stresses arisen in LZ layer and YSZ layer will increase while residual stress in substrate will decrease.

A Theoretical Model for Predicting Residual Stress Generation in Fabrication Process of Double-Ceramic-Layer Thermal Barrier Coating System

PubMed Central

Song, Yan; Wu, Weijie; Xie, Feng; Liu, Yilun; Wang, Tiejun

2017-01-01

Residual stress arisen in fabrication process of Double-Ceramic-Layer Thermal Barrier Coating System (DCL-TBCs) has a significant effect on its quality and reliability. In this work, based on the practical fabrication process of DCL-TBCs and the force and moment equilibrium, a theoretical model was proposed at first to predict residual stress generation in its fabrication process, in which the temperature dependent material properties of DCL-TBCs were incorporated. Then, a Finite Element method (FEM) has been carried out to verify our theoretical model. Afterwards, some important geometric parameters for DCL-TBCs, such as the thickness ratio of stabilized Zirconia (YSZ, ZrO2-8%Y2O3) layer to Lanthanum Zirconate (LZ, La2Zr2O7) layer, which is adjustable in a wide range in the fabrication process, have a remarkable effect on its performance, therefore, the effect of this thickness ratio on residual stress generation in the fabrication process of DCL-TBCs has been systematically studied. In addition, some thermal spray treatment, such as the pre-heating treatment, its effect on residual stress generation has also been studied in this work. It is found that, the final residual stress mainly comes from the cooling down process in the fabrication of DCL-TBCs. Increasing the pre-heating temperature can obviously decrease the magnitude of residual stresses in LZ layer, YSZ layer and substrate. With the increase of the thickness ratio of YSZ layer to LZ layer, magnitudes of residual stresses arisen in LZ layer and YSZ layer will increase while residual stress in substrate will decrease. PMID:28103275

Fabrication of large area woodpile structure in polymer

NASA Astrophysics Data System (ADS)

Gupta, Jaya Prakash; Dutta, Neilanjan; Yao, Peng; Sharkawy, Ahmed S.; Prather, Dennis W.

2009-02-01

A fabrication process of three-dimensional Woodpile photonic crystals based on multilayer photolithography from commercially available photo resist SU8 have been demonstrated. A 6-layer, 2 mm × 2mm woodpile has been fabricated. Different factors that influence the spin thickness on multiple resist application have been studied. The fabrication method used removes, the problem of intermixing, and is more repeatable and robust than the multilayer fabrication techniques for three dimensional photonic crystal structures that have been previously reported. Each layer is developed before next layer photo resist spin, instead of developing the whole structure in the final step as used in multilayer process. The desired thickness for each layer is achieved by the calibration of spin speed and use of different photo resist compositions. Deep UV exposure confinement has been the defining parameter in this process. Layer uniformity for every layer is independent of the previous developed layers and depends on the photo resist planarizing capability, spin parameters and baking conditions. The intermixing problem, which results from the previous layers left uncrossed linked photo resist, is completely removed in this process as the previous layers are fully developed, avoiding any intermixing between the newly spun and previous layers. Also this process gives the freedom to redo every spin any number of times without affecting the previously made structure, which is not possible in other multilayer process where intermediate developing is not performed.

High-throughput preparation of complex multi-scale patterns from block copolymer/homopolymer blend films

NASA Astrophysics Data System (ADS)

Park, Hyungmin; Kim, Jae-Up; Park, Soojin

2012-02-01

A simple, straightforward process for fabricating multi-scale micro- and nanostructured patterns from polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP)/poly(methyl methacrylate) (PMMA) homopolymer in a preferential solvent for PS and PMMA is demonstrated. When the PS-b-P2VP/PMMA blend films were spin-coated onto a silicon wafer, PS-b-P2VP micellar arrays consisting of a PS corona and a P2VP core were formed, while the PMMA macrodomains were isolated, due to the macrophase separation caused by the incompatibility between block copolymer micelles and PMMA homopolymer during the spin-coating process. With an increase of PMMA composition, the size of PMMA macrodomains increased. Moreover, the P2VP blocks have a strong interaction with a native oxide of the surface of the silicon wafer, so that the P2VP wetting layer was first formed during spin-coating, and PS nanoclusters were observed on the PMMA macrodomains beneath. Whereas when a silicon surface was modified with a PS brush layer, the PS nanoclusters underlying PMMA domains were not formed. The multi-scale patterns prepared from copolymer micelle/homopolymer blend films are used as templates for the fabrication of gold nanoparticle arrays by incorporating the gold precursor into the P2VP chains. The combination of nanostructures prepared from block copolymer micellar arrays and macrostructures induced by incompatibility between the copolymer and the homopolymer leads to the formation of complex, multi-scale surface patterns by a simple casting process.A simple, straightforward process for fabricating multi-scale micro- and nanostructured patterns from polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP)/poly(methyl methacrylate) (PMMA) homopolymer in a preferential solvent for PS and PMMA is demonstrated. When the PS-b-P2VP/PMMA blend films were spin-coated onto a silicon wafer, PS-b-P2VP micellar arrays consisting of a PS corona and a P2VP core were formed, while the PMMA macrodomains were isolated, due to the macrophase separation caused by the incompatibility between block copolymer micelles and PMMA homopolymer during the spin-coating process. With an increase of PMMA composition, the size of PMMA macrodomains increased. Moreover, the P2VP blocks have a strong interaction with a native oxide of the surface of the silicon wafer, so that the P2VP wetting layer was first formed during spin-coating, and PS nanoclusters were observed on the PMMA macrodomains beneath. Whereas when a silicon surface was modified with a PS brush layer, the PS nanoclusters underlying PMMA domains were not formed. The multi-scale patterns prepared from copolymer micelle/homopolymer blend films are used as templates for the fabrication of gold nanoparticle arrays by incorporating the gold precursor into the P2VP chains. The combination of nanostructures prepared from block copolymer micellar arrays and macrostructures induced by incompatibility between the copolymer and the homopolymer leads to the formation of complex, multi-scale surface patterns by a simple casting process. Electronic supplementary information (ESI) available: AFM images of PS-b-P2VP/PMMA blend films and cross-sectional line scans. See DOI: 10.1039/c2nr11792d

Fabrication of a microfluidic chip by UV bonding at room temperature for integration of temperature-sensitive layers

NASA Astrophysics Data System (ADS)

Schlautmann, S.; Besselink, G. A. J.; Radhakrishna Prabhu, G.; Schasfoort, R. B. M.

2003-07-01

A method for the bonding of a microfluidic device at room temperature is presented. The wafer with the fluidic structures was bonded to a sensor wafer with gold pads by means of adhesive bonding, utilizing an UV-curable glue layer. To avoid filling the fluidic channels with the glue, a stamping process was developed which allows the selective application of a thin glue layer. In this way a microfluidic glass chip was fabricated that could be used for performing surface plasmon resonance measurements without signs of leakage. The advantage of this method is the possibility of integration of organic layers as well as other temperature-sensitive layers into a microfluidic glass device.

Fabrication of silicon-on-diamond substrate with an ultrathin SiO2 bonding layer

NASA Astrophysics Data System (ADS)

Nagata, Masahiro; Shirahama, Ryouya; Duangchan, Sethavut; Baba, Akiyoshi

2018-06-01

We proposed and demonstrated a sputter etching method to prepare both a flat surface (root-mean-square surface roughness of approximately 0.2–0.3 nm) and an ultrathin SiO2 bonding layer at an accuracy of approximately 5 nm in thickness to fabricate a silicon-on-diamond substrate (SOD). We also investigated a plasma activation method on a SiO2 surface using various gases. We found that O2 plasma activation is more suitable for the bonding between SiO2 and Si than N2 or Ar plasma activation. We speculate that the concentration of hydroxyl groups on the SiO2 surface was increased by O2 plasma activation. We fabricated the SOD substrate with an ultrathin (15 nm in thickness) SiO2 bonding layer using the sputter etching and O2 plasma activation methods.

Method of fabricating an optoelectronic device having a bulk heterojunction

DOEpatents

Shtein, Max [Princeton, NJ; Yang, Fan [Princeton, NJ; Forrest, Stephen R [Princeton, NJ

2008-09-02

A method of fabricating an organic optoelectronic device having a bulk heterojunction comprises the steps of: depositing a first layer over a first electrode by organic vapor phase deposition, wherein the first layer comprises a first organic small molecule material; depositing a second layer on the first layer such that the second layer is in physical contact with the first layer, wherein the interface of the second layer on the first layer forms a bulk heterojunction; and depositing a second electrode over the second layer to form the optoelectronic device. In another embodiment, a first layer having protrusions is deposited over the first electrode, wherein the first layer comprises a first organic small molecule material. For example, when the first layer is an electron donor layer, the first electrode is an anode, the second layer is an electron acceptor layer, and the second electrode is a cathode. As a further example, when the first layer is an electron acceptor layer, the first electrode is a cathode, the second layer is an electron donor layer, and the second electrode is an anode.

Cd-free Cu-Zn-In-S/ZnS quantum dots@SiO2 multiple cores nanostructure: preparation and application for white LEDs

NASA Astrophysics Data System (ADS)

Jiang, Tongtong; Shen, Mohan; Dai, Peng; Wu, Mingzai; Yu, Xinxin; Li, Guang; Xu, Xiaoliang; Zeng, Haibo

2017-10-01

The work reports the fabrication of Cu doped Zn-In-S (CZIS) alloy quantum dots (QDs) using dodecanethiol and oleic acid as stabilizing ligands. With the increase of doped Cu element, the photoluminescence (PL) peak is monotonically red shifted. After coating ZnS shell, the PL quantum yield of CZIS QDs can reach 78%. Using reverse micelle microemulsion method, CZIS/ZnS QDs@SiO2 multi-core nanospheres were synthesized to improve the colloidal stability and avoid the aggregation of QDs. The obtained multi-core nanospheres were dispersed in curing adhesive, and applied as a color conversion layer in down converted light-emitting diodes. After encapsulation in curing adhesive, the newly designed LEDs show artifically regulated color coordinates with varying the weight ratio of green QDs and red QDs, and the concentrations of these two types of QDs. Moreover, natural white and warm white LEDs with correlated color temperature of 5287, 6732, 2731, and 3309 K can be achieved, which indicates that CZIS/ZnS QDs@SiO2 nanostructures are promising color conversion layer material for solid-state lighting application.

Application of advanced structure to multi-tone mask for FPD process

NASA Astrophysics Data System (ADS)

Song, Jin-Han; Jeong, Jin-Woong; Kim, Kyu-Sik; Jeong, Woo-Gun; Yun, Sang-Pil; Lee, Dong-Heok; Choi, Sang-Soo

2017-07-01

In accordance with improvement of FPD technology, masks such as phase shift mask (PSM) and multi-tone mask (MTM) for a particular purpose also have been developed. Above all, the MTM consisted of more than tri-tone transmittance has a substantial advantage which enables to reduce the number of mask demand in FPD fabrication process contrast to normal mask of two-tone transmittance.[1,2] A chromium (Cr)-based MTM (Typically top type) is being widely employed because of convenience of etch process caused by its only Cr-based structure consisted of Cr absorber layer and Cr half-tone layer. However, the top type of Cr-based MTM demands two Cr sputtering processes after each layer etching process and writing process. For this reason, a different material from the Cr-based MTM is required for reduction of mask fabrication time and cost. In this study, we evaluate a MTM which has a structure combined Cr with molybdenum silicide (MoSi) to resolve the issues mentioned above. The MoSi which is demonstrated by integrated circuit (IC) process is a suitable material for MTM evaluation. This structure could realize multi-transmittance in common with the Cr-based MTM. Moreover, it enables to reduce the number of sputtering process. We investigate a optimized structure upon consideration of productivity along with performance such as critical dimension (CD) variation and transmittance range of each structure. The transmittance is targeted at h-line wavelength (405 nm) in the evaluation. Compared with Cr-based MTM, the performances of all Cr-/MoSi-based MTMs are considered.

Organic photovoltaic device with interfacial layer and method of fabricating same

DOEpatents

Marks, Tobin J.; Hains, Alexander W.

2013-03-19

An organic photovoltaic device and method of forming same. In one embodiment, the organic photovoltaic device has an anode, a cathode, an active layer disposed between the anode and the cathode; and an interfacial layer disposed between the anode and the active layer, the interfacial layer comprising 5,5'-bis[(p-trichlorosilylpropylphenyl)phenylamino]-2,2'-bithiophene (PABTSi.sub.2).

Superconducting Qubit with Integrated Single Flux Quantum Controller Part I: Theory and Fabrication

NASA Astrophysics Data System (ADS)

Beck, Matthew; Leonard, Edward, Jr.; Thorbeck, Ted; Zhu, Shaojiang; Howington, Caleb; Nelson, Jj; Plourde, Britton; McDermott, Robert

As the size of quantum processors grow, so do the classical control requirements. The single flux quantum (SFQ) Josephson digital logic family offers an attractive route to proximal classical control of multi-qubit processors. Here we describe coherent control of qubits via trains of SFQ pulses. We discuss the fabrication of an SFQ-based pulse generator and a superconducting transmon qubit on a single chip. Sources of excess microwave loss stemming from the complex multilayer fabrication of the SFQ circuit are discussed. We show how to mitigate this loss through judicious choice of process workflow and appropriate use of sacrificial protection layers. Present address: IBM T.J. Watson Research Center.

Applying macromolecular crowding to 3D bioprinting: fabrication of 3D hierarchical porous collagen-based hydrogel constructs.

PubMed

Ng, Wei Long; Goh, Min Hao; Yeong, Wai Yee; Naing, May Win

2018-02-27

Native tissues and/or organs possess complex hierarchical porous structures that confer highly-specific cellular functions. Despite advances in fabrication processes, it is still very challenging to emulate the hierarchical porous collagen architecture found in most native tissues. Hence, the ability to recreate such hierarchical porous structures would result in biomimetic tissue-engineered constructs. Here, a single-step drop-on-demand (DOD) bioprinting strategy is proposed to fabricate hierarchical porous collagen-based hydrogels. Printable macromolecule-based bio-inks (polyvinylpyrrolidone, PVP) have been developed and printed in a DOD manner to manipulate the porosity within the multi-layered collagen-based hydrogels by altering the collagen fibrillogenesis process. The experimental results have indicated that hierarchical porous collagen structures could be achieved by controlling the number of macromolecule-based bio-ink droplets printed on each printed collagen layer. This facile single-step bioprinting process could be useful for the structural design of collagen-based hydrogels for various tissue engineering applications.

Detecting Water Bodies in LANDSAT8 Oli Image Using Deep Learning

NASA Astrophysics Data System (ADS)

Jiang, W.; He, G.; Long, T.; Ni, Y.

2018-04-01

Water body identifying is critical to climate change, water resources, ecosystem service and hydrological cycle. Multi-layer perceptron(MLP) is the popular and classic method under deep learning framework to detect target and classify image. Therefore, this study adopts this method to identify the water body of Landsat8. To compare the performance of classification, the maximum likelihood and water index are employed for each study area. The classification results are evaluated from accuracy indices and local comparison. Evaluation result shows that multi-layer perceptron(MLP) can achieve better performance than the other two methods. Moreover, the thin water also can be clearly identified by the multi-layer perceptron. The proposed method has the application potential in mapping global scale surface water with multi-source medium-high resolution satellite data.

Epoxy bond and stop etch fabrication method

DOEpatents

Simmons, Jerry A.; Weckwerth, Mark V.; Baca, Wes E.

2000-01-01

A class of epoxy bond and stop etch (EBASE) microelectronic fabrication techniques is disclosed. The essence of such techniques is to grow circuit components on top of a stop etch layer grown on a first substrate. The first substrate and a host substrate are then bonded together so that the circuit components are attached to the host substrate by the bonding agent. The first substrate is then removed, e.g., by a chemical or physical etching process to which the stop etch layer is resistant. EBASE fabrication methods allow access to regions of a device structure which are usually blocked by the presence of a substrate, and are of particular utility in the fabrication of ultrafast electronic and optoelectronic devices and circuits.

Yarn-dyed fabric defect classification based on convolutional neural network

NASA Astrophysics Data System (ADS)

Jing, Junfeng; Dong, Amei; Li, Pengfei; Zhang, Kaibing

2017-09-01

Considering that manual inspection of the yarn-dyed fabric can be time consuming and inefficient, we propose a yarn-dyed fabric defect classification method by using a convolutional neural network (CNN) based on a modified AlexNet. CNN shows powerful ability in performing feature extraction and fusion by simulating the learning mechanism of human brain. The local response normalization layers in AlexNet are replaced by the batch normalization layers, which can enhance both the computational efficiency and classification accuracy. In the training process of the network, the characteristics of the defect are extracted step by step and the essential features of the image can be obtained from the fusion of the edge details with several convolution operations. Then the max-pooling layers, the dropout layers, and the fully connected layers are employed in the classification model to reduce the computation cost and extract more precise features of the defective fabric. Finally, the results of the defect classification are predicted by the softmax function. The experimental results show promising performance with an acceptable average classification rate and strong robustness on yarn-dyed fabric defect classification.

Graphene interfaced perovskite solar cells: Role of graphene flake size

NASA Astrophysics Data System (ADS)

Sakorikar, Tushar; Kavitha, M. K.; Tong, Shi Wun; Vayalamkuzhi, Pramitha; Loh, Kian Ping; Jaiswal, Manu

2018-04-01

Graphene interfaced inverted planar heterojunction perovskite solar cells are fabricated by facile solution method and studied its potential as hole conducting layer. Reduced graphene oxide (rGO) with small and large flake size and Polyethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS) are utilized as hole conducting layers in different devices. For the solar cell employing PEDOT:PSS as hole conducting layer, 3.8 % photoconversion efficiency is achieved. In case of solar cells fabricated with rGO as hole conducting layer, the efficiency of the device is strongly dependent on flake size. With all other fabrication conditions kept constant, the efficiency of graphene-interfaced solar cell improves by a factor of 6, by changing the flake size of graphene oxide. We attribute this effect to uniform coverage of graphene layer and improved electrical percolation network.

Electrochemical layer-by-layer approach to fabricate mechanically stable platinum black microelectrodes using a mussel-inspired polydopamine adhesive

NASA Astrophysics Data System (ADS)

Kim, Raeyoung; Nam, Yoonkey

2015-04-01

Objective. Platinum black (PtBK) has long been used for microelectrode fabrication owing to its high recording performance of neural signals. The porous structure of PtBK enlarges the surface area and lowers the impedance, which results in background noise reduction. However, the brittleness of PtBK has been a problem in practice. In this work, we report mechanically stable PtBK microelectrodes using a bioinspired adhesive film, polydopamine (pDA), while maintaining the low impedance of PtBK. Approach. The pDA layer was incorporated into the PtBK structure through electrochemical layer-by-layer deposition. Varying the number of layers and the order of materials, multi-layered pDA-PtBK hybrids were fabricated and the electrical properties, both impedance and charge injection limit, were evaluated. Main results. Multilayered pDA-PtBK hybrids had electrical impedances as low as PtBK controls and charge injection limit twice larger than controls. For the 30 min-ultrasonication agitation test, impedance levels rarely changed for some of the pDA-PtBK hybrids indicating that the pDA improved the mechanical property of the PtBK structures. The pDA-PtBK hybrid microelectrodes readily recorded neural signals of cultured hippocampal neurons, where background noise levels and signal-to-noise were 2.43 ∼ 3.23 μVrms and 28.4 ∼ 69.1, respectively. Significance. The developed pDA-PtBK hybrid microelectrodes are expected to be applicable to neural sensors for neural prosthetic studies.

Biodegradable neural cell culture sheet made of poly(lactic-co-glycolic acid) thin film with micropatterns of Dulbecco’s phosphate-buffered saline (-) containing laminin layers

NASA Astrophysics Data System (ADS)

Nakamura, Yuki; Horiuchi, Shunpu; Nishioka, Yasushiro

2018-02-01

In the regenerative medicine field of nervous systems, techniques used to fabricate microstructures of neurons on flexible and biodegradable substrates have attracted attention. In this research, biodegradable and flexible neuron culture thin films that enable the selective axonal outgrowth of neurons were fabricated using poly(lactic-co-glycolic acid) (PLGA) thin films with micropatterns of Dulbecco’s phosphate-buffered saline (D-PBS) (-) containing laminin layers. The 100-µm-thick PLGA thin films were fabricated by diluting PLGA in acetone (5% w/w) and the solution was distributed onto a poly(dimethylsiloxane) (PDMS) mold. D-PBS (-) micropatterns containing laminin layers with widths of 10-150 µm were fabricated by micromolding in capillaries (MIMIC) and the microstencil method. Rat neurons were selectively cultured for 3 d on the laminin micropatterns; using the MIMIC method, the cells properly adhered to a pattern wider than 30 µm, while with the microstencil method, the necessary pattern width for proper adhesion was more than 50 µm.

Single layer multi-color luminescent display and method of making

NASA Technical Reports Server (NTRS)

Robertson, James B. (Inventor)

1992-01-01

The invention is a multi-color luminescent display comprising an insulator substrate and a single layer of host material, which may be a phosphor deposited thereon that hosts one or more different impurities, therein forming a pattern of selected and distinctly colored phosphors such as blue, green, and red phosphors in a single layer of host material. Transparent electrical conductor means may be provided for subjecting selected portions of the pattern of colored phosphors to an electric field, thereby forming a multi-color, single layer electroluminescent display. A method of forming a multi-color luminescent display includes the steps of depositing on an insulator substrate a single layer of host material, which itself may be a phosphor, with the properties to host varying quantities of different impurities and introducing one or more of said different impurities into selected areas of the said single layer of host material by thermal diffusion or ion implantation to form a pattern of phosphors of different colors in the said single layer of host material.

Fabrication of a printed capacitive air-gap touch sensor

NASA Astrophysics Data System (ADS)

Lee, Sang Hoon; Seo, Hwiwon; Lee, Sangyoon

2018-05-01

Unlike lithography-based processes, printed electronics does not require etching, which makes it difficult to fabricate electronic devices with an air gap. In this study, we propose a method to fabricate capacitive air-gap touch sensors via printing and coating. First, the bottom electrode was fabricated on a flexible poly(ethylene terephthalate) (PET) substrate using roll-to-roll gravure printing with silver ink. Then poly(dimethylsiloxane) (PDMS) was spin coated to form a sacrificial layer. The top electrode was fabricated on the sacrificial layer by spin coating with a stretchable silver ink. The sensor samples were then put in a tetrabutylammonium (TBAF) bath to generate the air gap by removing the sacrificial layer. The capacitance of the samples was measured for verification, and the results show that the capacitance increases in proportion to the applied force from 0 to 2.5 N.

Electrochemical cells and methods of manufacturing the same

DOEpatents

Bazzarella, Ricardo; Slocum, Alexander H; Doherty, Tristan; Cross, III, James C

2015-11-03

Electrochemical cells and methods of making electrochemical cells are described herein. In some embodiments, an apparatus includes a multi-layer sheet for encasing an electrode material for an electrochemical cell. The multi-layer sheet including an outer layer, an intermediate layer that includes a conductive substrate, and an inner layer disposed on a portion of the conductive substrate. The intermediate layer is disposed between the outer layer and the inner layer. The inner layer defines an opening through which a conductive region of the intermediate layer is exposed such that the electrode material can be electrically connected to the conductive region. Thus, the intermediate layer can serve as a current collector for the electrochemical cell.

Biomimetic synthesis of sericin and silica hybrid colloidosomes for stimuli-responsive anti-cancer drug delivery systems.

PubMed

Yang, Ying; Cai, Yurong; Sun, Ning; Li, Ruijing; Li, Wenhua; Kundu, Subhas C; Kong, Xiangdong; Yao, Juming

2017-03-01

Colloidosomes are becoming popular due to their significant flexibility with respect to microcapsule functionality. This study reports a facile approach for synthesizing silica colloidosomes by using sericin microcapsule as the matrix in an environment-friendly method. The silica colloid arrangement on the sericin microcapsules are orchestrated by altering the reaction parameters. Doxorubicin (DOX), used as a hydrophilic anti-cancer drug model, is encapsulated into the colloidosomes in a mild aqueous solution and becomes stimuli-responsive to different external environments, including pH values, protease, and ionic strength are also observed. Colloidosomes with sub-monolayers, close-packed monolayers, and close-packed multi-layered SiO 2 colloid shells can be fabricated under the optimized reaction conditions. A flexible DOX release from colloidosomes can be obtained via modulating the SiO 2 colloid layer arrangement and thickness. The close-packed and multi-layered SiO 2 colloid shells can best protect the colloidosomes and delay the rapid cargo release. MG-63 cells are killed when doxorubicin is released from the microcapsules due to degradation in the microenvironment of cancer cells. The drug release period is prolonged as SiO 2 shell thickness and integrity increase. This work suggests that the hybrid colloidosomes can be effective in a bioactive molecule delivery system. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and electrochemical performance of multi-walled carbon nanotube/polyaniline/MnO 2 ternary coaxial nanostructures for supercapacitors

NASA Astrophysics Data System (ADS)

Li, Qiang; Liu, Jianhua; Zou, Jianhua; Chunder, Anindarupa; Chen, Yiqing; Zhai, Lei

Multi-walled carbon nanotube (MWCNT)/polyaniline (PANI)/MnO 2 (MPM) ternary coaxial structures are fabricated as supercapacitor electrodes via a simple wet chemical method. The electrostatic interaction between negative poly(4-styrenesulfonic acid) (PSS) molecules and positive Mn 2+ ions causes the generation of MnO 2 nanostructures on MWCNT surfaces while the introduction of PANI layers with appropriate thickness on MWCNT surfaces facilitates the formation of MWCNT/PANI/MnO 2 ternary coaxial structures. The thickness of PANI coatings is controlled by tuning the aniline/MWCNT ratio. The effect of PANI thickness on the subsequent MnO 2 nanoflakes attachment onto MWCNTs, and the MPM structures is investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FESEM). The results suggest that appropriate thickness of PANI layers is important for building MPM ternary coaxial structures without the agglomeration of MnO 2 nanoflakes. The MPM ternary coaxial structures provide large interaction area between the MnO 2 nanoflakes and electrolyte, and improve the electrochemical utilization of the hydrous MnO 2, and decrease the contact resistance between MnO 2 and PANI layer coated MWCNTs, leading to intriguing electrochemical properties for the applications in supercapacitors such as a specific capacitance of 330 Fg -1 and good cycle stability.

Electrical contacts for a thin-film semiconductor device

DOEpatents

Carlson, David E.; Dickson, Charles R.; D'Aiello, Robert V.

1989-08-08

A method of fabricating spaced-apart back contacts on a thin film of semiconductor material by forming strips of buffer material on top of the semiconductor material in locations corresponding to the desired dividing lines between back contacts, forming a film of metal substantially covering the semiconductor material and buffer strips, and scribing portions of the metal film overlying the buffer strips with a laser without contacting the underlying semiconductor material to separate the metal layer into a plurality of back contacts. The buffer material serves to protect the underlying semiconductor material from being damaged during the laser scribing. Back contacts and multi-cell photovoltaic modules incorporating such back contacts also are disclosed.

Pressure prediction model for compression garment design.

PubMed

Leung, W Y; Yuen, D W; Ng, Sun Pui; Shi, S Q

2010-01-01

Based on the application of Laplace's law to compression garments, an equation for predicting garment pressure, incorporating the body circumference, the cross-sectional area of fabric, applied strain (as a function of reduction factor), and its corresponding Young's modulus, is developed. Design procedures are presented to predict garment pressure using the aforementioned parameters for clinical applications. Compression garments have been widely used in treating burning scars. Fabricating a compression garment with a required pressure is important in the healing process. A systematic and scientific design method can enable the occupational therapist and compression garments' manufacturer to custom-make a compression garment with a specific pressure. The objectives of this study are 1) to develop a pressure prediction model incorporating different design factors to estimate the pressure exerted by the compression garments before fabrication; and 2) to propose more design procedures in clinical applications. Three kinds of fabrics cut at different bias angles were tested under uniaxial tension, as were samples made in a double-layered structure. Sets of nonlinear force-extension data were obtained for calculating the predicted pressure. Using the value at 0° bias angle as reference, the Young's modulus can vary by as much as 29% for fabric type P11117, 43% for fabric type PN2170, and even 360% for fabric type AP85120 at a reduction factor of 20%. When comparing the predicted pressure calculated from the single-layered and double-layered fabrics, the double-layered construction provides a larger range of target pressure at a particular strain. The anisotropic and nonlinear behaviors of the fabrics have thus been determined. Compression garments can be methodically designed by the proposed analytical pressure prediction model.

Thermal cycling and electrochemical characteristics of solid oxide fuel cell supported on stainless steel with a new 3-phase composite anode

NASA Astrophysics Data System (ADS)

Dayaghi, Amir Masoud; Kim, Kun Joong; Kim, Sun Jae; Kim, Sunwoong; Bae, Hongyeul; Choi, Gyeong Man

2017-06-01

We report design, fabrication method, and fast thermal-cycling ability of solid oxide fuel cells (SOFCs) that use stainless steel (STS) as a support, and a new 3-phase anode. La and Ni co-doped SrTiO3 (La0.2Sr0.8Ti0.9Ni0.1O3-d, LSTN), replaces some of the Ni in conventional Ni-yttria stabilized zirconia (YSZ) anode; the resultant LSTN-YSZ-Ni 3-phase-composite anode is tested as a new reduction (or decomposition)-resistant anode of STS-supported SOFCs that can be co-fired with STS. A multi-layered cell with YSZ electrolyte (thickness ∼5 μm), composite anode, STS-cermet contact-layer, and STS support is designed, then fabricated by tape casting, lamination, and co-firing at 1250 °C in reducing atmosphere. The maximum power density (MPD) is 325 mW cm-2 at 650 °C; this is one of the highest among STS-supported cells fabricated by co-firing. The cell also shows stable open-circuit voltage and Ohmic resistance during 100 rapid thermal cycles between 170 and 600 °C. STS support minimizes stress and avoids cracking of electrolyte during rapid thermal cycling. The excellent MPD and stability during thermal cycles, and promising characteristics of SOFC as a power source for vehicle or mobile devices that requires rapid thermal cycles, are attributed to the new design of the cell with new anode structure.

Thermally Cross-Linkable Hole Transport Materials for Solution Processed Phosphorescent OLEDs

NASA Astrophysics Data System (ADS)

Kim, Beom Seok; Kim, Ohyoung; Chin, Byung Doo; Lee, Chil Won

2018-04-01

Materials for unique fabrication of a solution-processed, multi-layered organic light-emitting diode (OLED) were developed. Preparation of a hole transport layer with a thermally cross-linkable chemical structure, which can be processed to form a thin film and then transformed into an insoluble film by using an amine-alcohol condensation reaction with heat treatment, was investigated. Functional groups, such as triplenylamine linked with phenylcarbazole or biphenyl, were employed in the chemical structure of the hole transport layer in order to maintain high triplet energy properties. When phenylcarbazole or biphenyl compounds continuously react with triphenylamine under acid catalysis, a chemically stable thin film material with desirable energy-level properties for a blue OLED could be obtained. The prepared hole transport materials showed excellent surface roughness and thermal stability in comparison with the commercial reference material. On the solution-processed model hole transport layer, we fabricated a device with a blue phosphorescent OLED by using sequential vacuum deposition. The maximum external quantum, 19.3%, was improved by more than 40% over devices with the commercial reference material (11.4%).

Method of fabricating conductive electrodes on the front and backside of a thin film structure

DOEpatents

Tabada, Phillipe J [Roseville, CA; Tabada, legal representative, Melody; Pannu, Satinderpall S [Pleasanton, CA

2011-05-22

A method of fabricating a thin film device having conductive front and backside electrodes or contacts. Top-side cavities are first formed on a first dielectric layer, followed by the deposition of a metal layer on the first dielectric layer to fill the cavities. Defined metal structures are etched from the metal layer to include the cavity-filled metal, followed by depositing a second dielectric layer over the metal structures. Additional levels of defined metal structures may be formed in a similar manner with vias connecting metal structures between levels. After a final dielectric layer is deposited, a top surface of a metal structure of an uppermost metal layer is exposed through the final dielectric layer to form a front-side electrode, and a bottom surface of a cavity-filled portion of a metal structure of a lowermost metal layer is also exposed through the first dielectric layer to form a back-side electrode.

Fabrication of polycrystalline thin films by pulsed laser processing

DOEpatents

Mitlitsky, Fred; Truher, Joel B.; Kaschmitter, James L.; Colella, Nicholas J.

1998-02-03

A method for fabricating polycrystalline thin films on low-temperature (or high-temperature) substrates which uses processing temperatures that are low enough to avoid damage to the substrate, and then transiently heating select layers of the thin films with at least one pulse of a laser or other homogenized beam source. The pulse length is selected so that the layers of interest are transiently heated to a temperature which allows recrystallization and/or dopant activation while maintaining the substrate at a temperature which is sufficiently low to avoid damage to the substrate. This method is particularly applicable in the fabrication of solar cells.

Fabrication of polycrystalline thin films by pulsed laser processing

DOEpatents

Mitlitsky, F.; Truher, J.B.; Kaschmitter, J.L.; Colella, N.J.

1998-02-03

A method is disclosed for fabricating polycrystalline thin films on low-temperature (or high-temperature) substrates which uses processing temperatures that are low enough to avoid damage to the substrate, and then transiently heating select layers of the thin films with at least one pulse of a laser or other homogenized beam source. The pulse length is selected so that the layers of interest are transiently heated to a temperature which allows recrystallization and/or dopant activation while maintaining the substrate at a temperature which is sufficiently low to avoid damage to the substrate. This method is particularly applicable in the fabrication of solar cells. 1 fig.

Mask fabrication process

DOEpatents

Cardinale, Gregory F.

2000-01-01

A method for fabricating masks and reticles useful for projection lithography systems. An absorber layer is conventionally patterned using a pattern and etch process. Following the step of patterning, the entire surface of the remaining top patterning photoresist layer as well as that portion of an underlying protective photoresist layer where absorber material has been etched away is exposed to UV radiation. The UV-exposed regions of the protective photoresist layer and the top patterning photoresist layer are then removed by solution development, thereby eliminating the need for an oxygen plasma etch and strip and chances for damaging the surface of the substrate or coatings.

Sensing human physiological response using wearable carbon nanotube-based fabrics

NASA Astrophysics Data System (ADS)

Wang, Long; Loh, Kenneth J.; Koo, Helen S.

2016-04-01

Flexible and wearable sensors for human monitoring have received increased attention. Besides detecting motion and physical activity, measuring human vital signals (e.g., respiration rate and body temperature) provide rich data for assessing subjects' physiological or psychological condition. Instead of using conventional, bulky, sensing transducers, the objective of this study was to design and test a wearable, fabric-like sensing system. In particular, multi-walled carbon nanotube (MWCNT)-latex thin films of different MWCNT concentrations were first fabricated using spray coating. Freestanding MWCNT-latex films were then sandwiched between two layers of flexible fabric using iron-on adhesive to form the wearable sensor. Second, to characterize its strain sensing properties, the fabric sensors were subjected to uniaxial and cyclic tensile load tests, and they exhibited relatively stable electromechanical responses. Finally, the wearable sensors were placed on a human subject for monitoring simple motions and for validating their practical strain sensing performance. Overall, the wearable fabric sensor design exhibited advances such as flexibility, ease of fabrication, light weight, low cost, noninvasiveness, and user comfort.

Method for forming a glove attachment

NASA Technical Reports Server (NTRS)

Dawn, Frederic S. (Inventor); Guy, Walter W. (Inventor); Kosmo, Joseph (Inventor); Drennan, Arthur P. (Inventor); Tschirch, Richard P. (Inventor)

1995-01-01

An attachment principally for the palm of an astronaut glove to enhance the gripping area of the palm without detracting from the flexibility and utility of the glove is presented. The attachment is a composite construction formed from a layer of silicone rubber having an outer surface with a friction configuration and another layer of silicone rubber in which a Nomex Aramid mesh fabric is embedded prior to curing. The method of construction involves the use of a mold with a friction configuration surface. A first layer of silicone rubber or sealant is disposed in the mold and allowed to set for an hour. A second layer of silicone rubber or sealant is layered over the first layer and leveled. A Nomex Aramid mesh fabric is embedded into the second layer and the composite is permitted to cure. When cured, a configured area of the composite construction is glued or stitched to the palm area of the glove.

Template Synthesis of Nanostructured Polymeric Membranes by Inkjet Printing.

PubMed

Gao, Peng; Hunter, Aaron; Benavides, Sherwood; Summe, Mark J; Gao, Feng; Phillip, William A

2016-02-10

The fabrication of functional nanomaterials with complex structures has been serving great scientific and practical interests, but current fabrication and patterning methods are generally costly and laborious. Here, we introduce a versatile, reliable, and rapid method for fabricating nanostructured polymeric materials. The novel method is based on a combination of inkjet printing and template synthesis, and its utility and advantages in the fabrication of polymeric nanomaterials is demonstrated through three examples: the generation of polymeric nanotubes, nanowires, and thin films. Layer-by-layer-assembled nanotubes can be synthesized in a polycarbonate track-etched (PCTE) membrane by printing poly(allylamine hydrochloride) and poly(styrenesulfonate) sequentially. This sequential deposition of polyelectrolyte ink enables control over the surface charge within the nanotubes. By a simple change of the printing conditions, polymeric nanotubes or nanowires were prepared by printing poly(vinyl alcohol) in a PCTE template. In this case, the high-throughput nature of the method enables functional nanomaterials to be generated in under 3 min. Furthermore, we demonstrate that inkjet printing paired with template synthesis can be used to generate patterns comprised of chemically distinct nanomaterials. Thin polymeric films of layer-by-layer-assembled poly(allylamine hydrochloride) and poly(styrenesulfonate) are printed on a PCTE membrane. Track-etched membranes covered with the deposited thin films reject ions and can potentially be utilized as nanofiltration membranes. When the fabrication of these different classes of nanostructured materials is demonstrated, the advantages of pairing template synthesis with inkjet printing, which include fast and reliable deposition, judicious use of the deposited materials, and the ability to design chemically patterned surfaces, are highlighted.

Multi-layer Lanczos iteration approach to calculations of vibrational energies and dipole transition intensities for polyatomic molecules

DOE PAGES

Yu, Hua-Gen

2015-01-28

We report a rigorous full dimensional quantum dynamics algorithm, the multi-layer Lanczos method, for computing vibrational energies and dipole transition intensities of polyatomic molecules without any dynamics approximation. The multi-layer Lanczos method is developed by using a few advanced techniques including the guided spectral transform Lanczos method, multi-layer Lanczos iteration approach, recursive residue generation method, and dipole-wavefunction contraction. The quantum molecular Hamiltonian at the total angular momentum J = 0 is represented in a set of orthogonal polyspherical coordinates so that the large amplitude motions of vibrations are naturally described. In particular, the algorithm is general and problem-independent. An applicationmore » is illustrated by calculating the infrared vibrational dipole transition spectrum of CH₄ based on the ab initio T8 potential energy surface of Schwenke and Partridge and the low-order truncated ab initio dipole moment surfaces of Yurchenko and co-workers. A comparison with experiments is made. The algorithm is also applicable for Raman polarizability active spectra.« less

A fully roll-to-roll gravure-printed carbon nanotube-based active matrix for multi-touch sensors

PubMed Central

Lee, Wookyu; Koo, Hyunmo; Sun, Junfeng; Noh, Jinsoo; Kwon, Kye-Si; Yeom, Chiseon; Choi, Younchang; Chen, Kevin; Javey, Ali; Cho, Gyoujin

2015-01-01

Roll-to-roll (R2R) printing has been pursued as a commercially viable high-throughput technology to manufacture flexible, disposable, and inexpensive printed electronic devices. However, in recent years, pessimism has prevailed because of the barriers faced when attempting to fabricate and integrate thin film transistors (TFTs) using an R2R printing method. In this paper, we report 20 × 20 active matrices (AMs) based on single-walled carbon nanotubes (SWCNTs) with a resolution of 9.3 points per inch (ppi) resolution, obtained using a fully R2R gravure printing process. By using SWCNTs as the semiconducting layer and poly(ethylene terephthalate) (PET) as the substrate, we have obtained a device yield above 98%, and extracted the key scalability factors required for a feasible R2R gravure manufacturing process. Multi-touch sensor arrays were achieved by laminating a pressure sensitive rubber onto the SWCNT-TFT AM. This R2R gravure printing system overcomes the barriers associated with the registration accuracy of printing each layer and the variation of the threshold voltage (Vth). By overcoming these barriers, the R2R gravure printing method can be viable as an advanced manufacturing technology, thus enabling the high-throughput production of flexible, disposable, and human-interactive cutting-edge electronic devices based on SWCNT-TFT AMs. PMID:26635237

Complete passive vibration suppression using multi-layered piezoelectric element, inductor, and resistor

NASA Astrophysics Data System (ADS)

Yamada, Keisuke

2017-01-01

This paper describes passive technique for suppressing vibration in flexible structures using a multi-layered piezoelectric element, an inductor, and a resistor. The objective of using a multi-layered piezoelectric element is to increase its capacitance. A piezoelectric element with a large capacitance value does not require an active electrical circuit to simulate an inductor with a large inductance value. The effect of multi-layering of piezoelectric elements was theoretically analyzed through an equivalent transformation of a multi-layered piezoelectric element into a single-layered piezoelectric element. The governing equations were derived using this equivalent transformation. The effect of the resistances of the inductor and piezoelectric elements were considered because the sum of these resistances may exceed the optimum resistance. The performance of the passive vibration suppression using an LR circuit was compared to that of the method where a resistive circuit is used assuming that the sum of the resistances of the inductor and piezoelectric elements exceeds the optimum resistance. The effectiveness of the proposed method and theoretical analysis was verified through simulations and experiments.

Spectral collocation method with a flexible angular discretization scheme for radiative transfer in multi-layer graded index medium

NASA Astrophysics Data System (ADS)

Wei, Linyang; Qi, Hong; Sun, Jianping; Ren, Yatao; Ruan, Liming

2017-05-01

The spectral collocation method (SCM) is employed to solve the radiative transfer in multi-layer semitransparent medium with graded index. A new flexible angular discretization scheme is employed to discretize the solid angle domain freely to overcome the limit of the number of discrete radiative direction when adopting traditional SN discrete ordinate scheme. Three radial basis function interpolation approaches, named as multi-quadric (MQ), inverse multi-quadric (IMQ) and inverse quadratic (IQ) interpolation, are employed to couple the radiative intensity at the interface between two adjacent layers and numerical experiments show that MQ interpolation has the highest accuracy and best stability. Variable radiative transfer problems in double-layer semitransparent media with different thermophysical properties are investigated and the influence of these thermophysical properties on the radiative transfer procedure in double-layer semitransparent media is also analyzed. All the simulated results show that the present SCM with the new angular discretization scheme can predict the radiative transfer in multi-layer semitransparent medium with graded index efficiently and accurately.

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.

Study on the electrical behavior of MWCNTs in GF/Epoxy composites.

PubMed

Yan, Zhao; Lu, Yuan; Yuexin, Duan

2010-08-01

The multi-wall nanotubes (MWCNTs) were divisionalized equably by the fabric of glass in composites. Then the electrical properties such as permittivity, conductance and electromagnetic interference (EMI) shielding effectiveness (SE) of MWCNTs in GF/EP composite were studied. The effect of the content and dispersion of MWCNTs were researched in this work. Firstly the permittivity of MWCNTs/GF/EP composites were studied respectively by keeping layers of glass fabric and increasing content of MWCNTs or keeping content of MWCNTs and changing layers of glass fabric in electromagnetic wave band (5.85-18 GHz). Then the conductance of MWCNTs/GF/EP composites with different MWCNTs contents was tested. Furthermore, the EMI SE of composites with different MWCNTs contents in electromagnetic wave band (5.85-18 GHz) were studied. In addition, the morphologies of MWCNTs/GF/EP composites with the different MWCNTs weight percent were observed. The results show that the real part of permittivity of composites can be improved highest up to 75 and the imaginary part increase maximum up to 80. However there is no disciplinarian about effect of layers of glass fabric on dielectric property. The MWCNTs/GF/EP composite can be changed from the insulator to the semiconductor along with increasing the weight percent of MWCNTs. In electromagnetic wave band 5.85-18 GHz, the values of SE are increasing with increasing content of the MWCNTs.

Generalized Low-Temperature Fabrication of Scalable Multi-Type Two-Dimensional Nanosheets with a Green Soft Template.

PubMed

Wang, Lanfang; Song, Chuang; Shi, Yi; Dang, Liyun; Jin, Ying; Jiang, Hong; Lu, Qingyi; Gao, Feng

2016-04-11

Two-dimensional nanosheets with high specific surface areas and fascinating physical and chemical properties have attracted tremendous interests because of their promising potentials in both fundamental research and practical applications. However, the problem of developing a universal strategy with a facile and cost-effective synthesis process for multi-type ultrathin 2 D nanostructures remains unresolved. Herein, we report a generalized low-temperature fabrication of scalable multi-type 2 D nanosheets including metal hydroxides (such as Ni(OH)2, Co(OH)2, Cd(OH)2, and Mg(OH)2), metal oxides (such as ZnO and Mn3O4), and layered mixed transition-metal hydroxides (Ni-Co LDH, Ni-Fe LDH, Co-Fe LDH, and Ni-Co-Fe layered ternary hydroxides) through the rational employment of a green soft-template. The synthesized crystalline inorganic nanosheets possess confined thickness, resulting in ultrahigh surface atom ratios and chemically reactive facets. Upon evaluation as electrode materials for pseudocapacitors, the Ni-Co LDH nanosheets exhibit a high specific capacitance of 1087 F g(-1) at a current density of 1 A g(-1), and excellent stability, with 103% retention after 500 cycles. This strategy is facile and scalable for the production of high-quality ultrathin crystalline inorganic nanosheets, with the possibility of extension to the preparation of other complex nanosheets. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ag/C:F Antibacterial and hydrophobic nanocomposite coatings

NASA Astrophysics Data System (ADS)

Kylián, Ondřej; Kratochvíl, Jiří; Petr, Martin; Kuzminova, Anna; Slavínská, Danka; Biederman, Hynek; Beranová, Jana

Silver-based nanomaterials that exhibit antibacterial character are intensively studied as they represent promising weapon against multi-drug resistant bacteria. Equally important class of materials represent coatings that have highly water repellent nature. Such materials may be used for fabrication of anti-fogging or self-cleaning surfaces. The aim of this study is to combine both of these valuable material characteristics. Antibacterial and highly hydrophobic Ag/C:F nanocomposite films were fabricated by means of gas aggregation source of Ag nanoparticles and sputter deposition of C:F matrix. The nanocomposite coatings had three-layer structure C:F base layer/Ag nanoparticles/C:F top layer. It is shown that the increasing number of Ag nanoparticles in produced coatings leads not only in enhancement of their antibacterial activity, but also causes substantial increase of their hydrophobicity. Under optimized conditions, the coatings are super-hydrophobic with water contact angle equal to 165∘ and are capable to induce 6-log reduction of bacteria presented in solution within 4h.

Transparent Carbon Nanotube layers as cathodes in OLEDs

NASA Astrophysics Data System (ADS)

Papadimitratos, Alexios; Nasibulin, Albert; Kauppinen, Esko; Zakhidov, Anvar; Solarno Inc Collaboration; Aalto University Collaboration; UT Dallas Collaboration

2011-03-01

Organic Light Emitting diodes (OLEDs) have attracted high interest in recent years due to their potential use in future lighting and display applications. Reported work on OLEDs traditionally utilizes low work function materials as cathodes that are expensive to fabricate because of the high vacuum processing. Transparent carbon nanotube (CNT) sheets have excellent mechanical and electrical properties. We have already shown earlier that multi-wall (MWCNT) as well as single CNT (SWCNT) sheets can be used as effective anodes in bright OLEDs [,]. The true advantage of using the CNT sheets lies in flexible devices and new architectures with CNT sheet as layers in tandem devices with parallel connection. In this work, we are investigating the possibility of using SWCNT as cathodes in OLEDs. SWCNT sheets have been reported to show lower work function compared to MWCNT. Our work attempts to demonstrate transparent OLED devices with CNT anodes and cathodes. In the process, OLEDs with CNT cathodes have been fabricated in normal and inverted configurations using inorganic oxides (MoO3,ZnO) as invertion layers.

Very High Speed Integrated Circuits - VHSIC - Final Program Repoort

DTIC Science & Technology

1990-09-30

emphasis ill ordeFr to (U hieci’ the i/ urease (I mIliitdF capa)(bility L’XI)L’t(’d /)1omn its resiuIh x.’ -Ricluard J). [)ehaitr. Undicer Sec reta/vy...Many new and difficult fabrication problems had to be solved, especially in the areas of silicon substrate material, fine-line lithography, multi- layer ...toward submicron geometries, even in the commercial world ." "Among the technical breakthrou hs spawned by VHSIC is the use of multiple layers of wetal

A Novel MUMPs-compatible single-layer out-of-plane electrothermal actuator

NASA Astrophysics Data System (ADS)

Tang, Weider; Wu, Mingching; Ho, Yi-Ping; Yeh, Mau-Shium; Fang, Weileun

2002-11-01

Microactuator is one of the key components for the microelectromechanical systems (MEMS), and it can be categorized as out-of-plane and in-plane according to the motion types. Most of the existing out-of-plane thermal actuators are multi-layer structures. In this paper, a novel electrothermal single-layer out-of-plane actuator is provided and it characteristics and advantages of this device are stated as follows: (1) This actuator is consisted of only a single thin film material, therefore, it can prevent from delaminating after a long-term operation. Besides, owing to its symmetric geometric design, the inner-beams of this structure don"t have any current passed through them and the inner-beams also provide a geometric constraint to allow the two free ends of the structure to bend upwards symmetrically. (2) This device can be operated at a relative low voltage (<5 volt), and deflected upwards about 4 μm in the experiment test. Besides, the fabrication process is very simple and it is MUMPs(Multi-User MEMS Processes)-compatible. Presently, a prototype structure has been successfully fabricated and tested. This structure offers the potential applications in the adaptive optics systems, and Fabry-Perot filters, etc. Besides, it also provides an interface to cooperate with integrated circuits (IC) and various optical elements to construct an embedded-control optical system.

CHEMICAL SOLUTION DEPOSITION BASED OXIDE BUFFERS AND YBCO COATED CONDUCTORS

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

Paranthaman, Mariappan Parans

We have reviewed briefly the growth of buffer and high temperature superconducting oxide thin films using a chemical solution deposition (CSD) method. In the Rolling-Assisted Biaxially Textured Substrates (RABiTS) process, developed at Oak Ridge National Laboratory, utilizes the thermo mechanical processing to obtain the flexible, biaxially oriented copper, nickel or nickel-alloy substrates. Buffers and Rare Earth Barium Copper Oxide (REBCO) superconductors have been deposited epitaxially on the textured nickel alloy substrates. The starting substrate serves as a template for the REBCO layer, which has substantially fewer weak links. Buffer layers play a major role in fabricating the second generation REBCOmore » wire technology. The main purpose of the buffer layers is to provide a smooth, continuous and chemically inert surface for the growth of the REBCO film, while transferring the texture from the substrate to the superconductor layer. To achieve this, the buffer layers need to be epitaxial to the substrate, i.e. they have to nucleate and grow in the same bi-axial texture provided by the textured metal foil. The most commonly used RABiTS multi-layer architectures consist of a starting template of biaxially textured Ni-5 at.% W (Ni-W) substrate with a seed (first) layer of Yttrium Oxide (Y2O3), a barrier (second) layer of Yttria Stabilized Zirconia (YSZ), and a Cerium Oxide (CeO2) cap (third) layer. These three buffer layers are generally deposited using physical vapor deposition (PVD) techniques such as reactive sputtering. On top of the PVD template, REBCO film is then grown by a chemical solution deposition. This article reviews in detail about the list of oxide buffers and superconductor REBCO films grown epitaxially on single crystal and/or biaxially textured Ni-W substrates using a CSD method.« less

Dynamic Shock Compression of Copper to Multi-Megabar Pressure

NASA Astrophysics Data System (ADS)

Haill, T. A.; Furnish, M. D.; Twyeffort, L. L.; Arrington, C. L.; Lemke, R. W.; Knudson, M. D.; Davis, J.-P.

2015-11-01

Copper is an important material for a variety of shock and high energy density applications and experiments. Copper is used as a standard reference material to determine the EOS properties of other materials. The high conductivity of copper makes it useful as an MHD driver layer in high current dynamic materials experiments on Sandia National Laboratories Z machine. Composite aluminum/copper flyer plates increase the dwell time in plate impact experiments by taking advantage of the slower wave speeds in copper. This presentation reports on recent efforts to reinstate a composite Al/Cu flyer capability on Z and to extend the range of equation-of-state shock compression data through the use of hyper-velocity composite flyers and symmetric planar impact with copper targets. We will present results from multi-dimensional ALEGRA MHD simulations, as well as experimental designs and methods of composite flyer fabrication. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. DOE's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Chitosan-Sodium Phytate Films with a Strong Water Barrier and Antimicrobial Properties Produced via One-Step-Consecutive-Stripping and Layer-by-Layer-Casting Technologies.

PubMed

Yang, Jie; Xiong, Liu; Li, Man; Sun, Qingjie

2018-06-20

The pursuit of sustainable functional materials requires the development of materials based on renewable resources and efficient fabrication methods. Here, we first fabricated chitosan-sodium phytate films via one-step-stripping and layer-by-layer-casting technologies. The proposed film-fabrication methods are general, facile, environmentally benign, cost-effective, and easy to scale up. The resultant one-step-stripped film was thin (9 ± 1 μm), soft, transparent, and strong, whereas the thickness of the layer-by-layer-cast film was 70 ± 3 μm. FTIR analysis of the films indicated the formation of interactions between the phosphoric groups in sodium phytate and the amino groups in chitosan. More importantly, the water-vapor-permeability values of the one-step-stripped and cast films were 4-5 orders of magnitude lower than chitosan films reported before. Layer-by-layer-cast films in particular exhibited high tensile strength (49.21 ± 1.12 MPa) and were more than three times stronger than other polyelectrolyte multilayer films. Both types of films remained stable in an acidic environment. Furthermore, the layer-by-layer-assembled films presented greater antimicrobial activity than the stripped films. The developed chitosan-sodium phytate films can enhance several biomedical and environmental applications, such as packaging, drug delivery, diagnostics, microfluidics, and biosensing.

New dichromated gelatin technologies for diffraction optical element fabrication

NASA Astrophysics Data System (ADS)

Vigovsky, Yury N.; Malov, Alexander N.; Malov, Sergey N.; Feshchenko, Valeriy S.; Konop, Sergey P.

1998-01-01

The hologram recording mechanism in the dichromated gelatin layers are discussed. A new technologies are described for red rainbow hologram recording in the photographic emulsion and selfdeveloped dichromated gelatin--glycerol layers. A new method is suggested and experimentally approbated for relief plastic replica of the rainbow hologram fabrication based on the tanning developed or bleached photographic emulsion. This method is modification of the old photographic `bromoil' process. Some aspects of the noncoherent hologram coping on the dichromated gelatin films are discussed too.

Photoinitiator-free 3D scaffolds fabricated by excimer laser photocuring.

PubMed

Farkas, Balázs; Dante, Silvia; Brandi, Fernando

2017-01-20

Photoinitiator-free fabrication of poly(ethylene glycol) diacrylate (PEGDA) scaffolds is achieved using a novel three-dimensional (3D) printing method called mask projected excimer laser stereolithography (MPExSL). The spatial resolution of photoinitiator-free curing is suitable for 3D layer-by-layer fabrication with a single layer thickness well controllable at tens to hundreds of microns using 248 nm wavelength for the irradiation. The photoinitiator-free scaffolds are superior compared to their counterparts fabricated by using photoinitiator molecules, showing a higher level of biocompatibility. A release of toxic chemicals from the photoinitiator containing scaffolds is proven by cell proliferation tests. In contrast, no toxic release is found from the photoinitiator-free scaffolds, resulting in the very same level of cell proliferation as the control sample. The demonstration of photoinitiator-free PEGDA scaffolds enables the fabrication of 3D scaffolds with the highest level of biocompatibility for both in vitro and in vivo applications.

Polymer Nanosheet Containing Star-Like Copolymers: A Novel Scalable Controlled Release System.

PubMed

Cao, Peng-Fei; de Leon, Al; Rong, Lihan; Yin, Ke-Zhen; Abenojar, Eric C; Su, Zhe; Tiu, Brylee David B; Exner, Agata A; Baer, Eric; Advincula, Rigoberto C

2018-04-26

Poly(ε-caprolactone) (PCL)-based nanomaterials, such as nanoparticles and liposomes, have exhibited great potential as controlled release systems, but the difficulties in large-scale fabrication limit their practical applications. Among the various methods being developed to fabricate polymer nanosheets (PNSs) for different applications, such as Langmuir-Blodgett technique and layer-by-layer assembly, are very effort consuming, and only a few PNSs can be obtained. In this paper, poly(ε-caprolactone)-based PNSs with adjustable thickness are obtained in large quantity by simple water exposure of multilayer polymer films, which are fabricated via a layer multiplying coextrusion method. The PNS is also demonstrated as a novel controlled guest release system, in which release kinetics are adjustable by the nanosheet thickness, pH values of the media, and the presence of protecting layers. Theoretical simulations, including Korsmeyer-Peppas model and Finite-element analysis, are also employed to discern the observed guest-release mechanisms. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multi-Layer Tiled Array.

DTIC Science & Technology

1996-12-16

the Invention 13 The present invention relates to planar sonar arrays. More 14 particularly, the invention relates to the arrangement of 15...transducer elements in planar sonar arrays. 16 (2) Description of the Prior Art 17 Conventional planar sonar array designs typically comprise 18 ceramic...signal 5 conditioners ( preamplifiers )/as short as possible. However, this 6 requirement complicates fabrication and provides little space to 7

Polymer taper bridge for silicon waveguide to single mode waveguide coupling

NASA Astrophysics Data System (ADS)

Kruse, Kevin; Middlebrook, Christopher T.

2016-03-01

Coupling of optical power from high-density silicon waveguides to silica optical fibers for signal routing can incur high losses and often requires complex end-face preparation/processing. Novel coupling device taper structures are proposed for low coupling loss between silicon photonic waveguides and single mode fibers are proposed and devices are fabricated and measured in terms of performance. Theoretical mode conversion models for waveguide tapers are derived for optimal device structure design and performance. Commercially viable vertical and multi-layer taper designs using polymer waveguide materials are proposed as innovative, cost-efficient, and mass-manufacturable optical coupling devices. The coupling efficiency for both designs is determined to evaluate optimal device dimensions and alignment tolerances with both silicon rib waveguides and silicon nanowire waveguides. Propagation loss as a function of waveguide roughness and metallic loss are determined and correlated to waveguide dimensions to obtain total insertion loss for the proposed taper designs. Multi-layer tapers on gold-sputtered substrates are fabricated through photolithography as proof-of-concept devices and evaluated for device loss optimization. Tapered waveguide coupling loss with Si WGs (2.74 dB) was experimentally measured with high correlation to theoretical results.

Development of a multi-element microdosimetric detector based on a thick gas electron multiplier

NASA Astrophysics Data System (ADS)

Anjomani, Z.; Hanu, A. R.; Prestwich, W. V.; Byun, S. H.

2017-03-01

A prototype multi-element gaseous microdosimetric detector was developed using the Thick Gas Electron Multiplier (THGEM) technique. The detector aims at measuring neutron and gamma-ray dose rates for weak neutron-gamma radiation fields. The multi-element design was employed to increase the neutron detection efficiency. The prototype THGEM multi-element detector consists of three layers of tissue equivalent plastic hexagons and each layer houses a hexagonal array of seven cylindrical gas cavity elements with equal heights and diameters of 17 mm. The final detector structure incorporates 21 gaseous volumes. Owing to the absence of wire electrodes, the THGEM multi-element detector offers flexible and convenient fabrication. The detector responses to neutron and gamma-ray were investigated using the McMaster Tandetron 7Li(p,n) neutron source. The dosimetric performance of the detector is presented in contrast to the response of a commercial tissue equivalent proportional counter. Compared to the standard TEPC response, the detector gave a consistent microdosimetric response with an average discrepancy of 8 % in measured neutron absorbed dose. An improvement of a factor of 3.0 in neutron detection efficiency has been accomplished with only a small degradation in energy resolution. However, its low energy cut off is about 6 keV/μm, which is not sufficient to measure the gamma-ray dose. This problem will be addressed by increasing the electron multiplication gain using double THGEM layers.

Electrochemical cells and methods of manufacturing the same

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

Bazzarella, Ricardo; Slocum, Alexander H.; Doherty, Tristan

2016-07-26

Electrochemical cells and methods of making electrochemical cells are described herein. In some embodiments, an apparatus includes a multi-layer sheet for encasing an electrode material for an electrochemical cell. The multi-layer sheet including an outer layer, an intermediate layer that includes a conductive substrate, and an inner layer disposed on a portion of the conductive substrate. The intermediate layer is disposed between the outer layer and the inner layer. The inner layer defines an opening through which a conductive region of the intermediate layer is exposed such that the electrode material can be electrically connected to the conductive region. Thus,more » the intermediate layer can serve as a current collector for the electrochemical cell.« less

Large scale integration of CVD-graphene based NEMS with narrow distribution of resonance parameters

NASA Astrophysics Data System (ADS)

Arjmandi-Tash, Hadi; Allain, Adrien; (Vitto Han, Zheng; Bouchiat, Vincent

2017-06-01

We present a novel method for the fabrication of the arrays of suspended micron-sized membranes, based on monolayer pulsed-CVD graphene. Such devices are the source of an efficient integration of graphene nano-electro-mechanical resonators, compatible with production at the wafer scale using standard photolithography and processing tools. As the graphene surface is continuously protected by the same polymer layer during the whole process, suspended graphene membranes are clean and free of imperfections such as deposits, wrinkles and tears. Batch fabrication of 100 μm-long multi-connected suspended ribbons is presented. At room temperature, mechanical resonance of electrostatically-actuated devices show narrow distribution of their characteristic parameters with high quality factor and low effective mass and resonance frequencies, as expected for low stress and adsorbate-free membranes. Upon cooling, a sharp increase of both resonant frequency and quality factor is observed, enabling to extract the thermal expansion coefficient of CVD graphene. Comparison with state-of-the-art graphene NEMS is presented.

A Flexible Temperature Sensor Based on Reduced Graphene Oxide for Robot Skin Used in Internet of Things.

PubMed

Liu, Guanyu; Tan, Qiulin; Kou, Hairong; Zhang, Lei; Wang, Jinqi; Lv, Wen; Dong, Helei; Xiong, Jijun

2018-05-02

Flexible electronics, which can be distributed on any surface we need, are highly demanded in the development of Internet of Things (IoT), robot technology and electronic skins. Temperature is a fundamental physical parameter, and it is an important indicator in many applications. Therefore, a flexible temperature sensor is required. Here, we report a simple method to fabricate three lightweight, low-cost and flexible temperature sensors, whose sensitive materials are reduced graphene oxide (r-GO), single-walled carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes (MWCNTs). By comparing linearity, sensitive and repeatability, we found that the r-GO temperature sensor had the most balanced performance. Furthermore, the r-GO temperature sensor showed good mechanical properties and it could be bent in different angles with negligible resistance change. In addition, the performance of the r-GO temperature sensor remained stable under different kinds of pressure and was unaffected by surrounding environments, like humidity or other gases, because of the insulating layer on its sensitive layer. The easy-fabricated process and economy, together with the remarkable performance of the r-GO temperature sensor, suggest that it is suitable for use as a robot skin or used in the environment of IoT.

Microfluidic channel fabrication method

DOEpatents

Arnold, Don W.; Schoeniger, Joseph S.; Cardinale, Gregory F.

2001-01-01

A new channel structure for microfluidic systems and process for fabricating this structure. In contrast to the conventional practice of fabricating fluid channels as trenches or grooves in a substrate, fluid channels are fabricated as thin walled raised structures on a substrate. Microfluidic devices produced in accordance with the invention are a hybrid assembly generally consisting of three layers: 1) a substrate that can or cannot be an electrical insulator; 2) a middle layer, that is an electrically conducting material and preferably silicon, forms the channel walls whose height defines the channel height, joined to and extending from the substrate; and 3) a top layer, joined to the top of the channels, that forms a cover for the channels. The channels can be defined by photolithographic techniques and are produced by etching away the material around the channel walls.

Fabrication of Well-Aligned ZnO Nanorods Using a Composite Seed Layer of ZnO Nanoparticles and Chitosan Polymer.

PubMed

Khun, Kimleang; Ibupoto, Zafar Hussain; AlSalhi, Mohamad S; Atif, Muhammad; Ansari, Anees A; Willander, Magnus

2013-09-30

In this study, by taking the advantage of both inorganic ZnO nanoparticles and the organic material chitosan as a composite seed layer, we have fabricated well-aligned ZnO nanorods on a gold-coated glass substrate using the hydrothermal growth method. The ZnO nanoparticles were characterized by the Raman spectroscopic techniques, which showed the nanocrystalline phase of the ZnO nanoparticles. Different composites of ZnO nanoparticles and chitosan were prepared and used as a seed layer for the fabrication of well-aligned ZnO nanorods. Field emission scanning electron microscopy, energy dispersive X-ray, high-resolution transmission electron microscopy, X-ray diffraction, and infrared reflection absorption spectroscopic techniques were utilized for the structural characterization of the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods on a gold-coated glass substrate. This study has shown that the ZnO nanorods are well-aligned, uniform, and dense, exhibit the wurtzite hexagonal structure, and are perpendicularly oriented to the substrate. Moreover, the ZnO nanorods are only composed of Zn and O atoms. An optical study was also carried out for the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods, and the obtained results have shown that the fabricated ZnO nanorods exhibit good crystal quality. This study has provided a cheap fabrication method for the controlled morphology and good alignment of ZnO nanorods, which is of high demand for enhancing the working performance of optoelectronic devices.

Fabrication of Well-Aligned ZnO Nanorods Using a Composite Seed Layer of ZnO Nanoparticles and Chitosan Polymer

PubMed Central

Khun, Kimleang; Ibupoto, Zafar Hussain; AlSalhi, Mohamad S.; Atif, Muhammad; Ansari, Anees A.; Willander, Magnus

2013-01-01

In this study, by taking the advantage of both inorganic ZnO nanoparticles and the organic material chitosan as a composite seed layer, we have fabricated well-aligned ZnO nanorods on a gold-coated glass substrate using the hydrothermal growth method. The ZnO nanoparticles were characterized by the Raman spectroscopic techniques, which showed the nanocrystalline phase of the ZnO nanoparticles. Different composites of ZnO nanoparticles and chitosan were prepared and used as a seed layer for the fabrication of well-aligned ZnO nanorods. Field emission scanning electron microscopy, energy dispersive X-ray, high-resolution transmission electron microscopy, X-ray diffraction, and infrared reflection absorption spectroscopic techniques were utilized for the structural characterization of the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods on a gold-coated glass substrate. This study has shown that the ZnO nanorods are well-aligned, uniform, and dense, exhibit the wurtzite hexagonal structure, and are perpendicularly oriented to the substrate. Moreover, the ZnO nanorods are only composed of Zn and O atoms. An optical study was also carried out for the ZnO nanoparticles/chitosan seed layer-coated ZnO nanorods, and the obtained results have shown that the fabricated ZnO nanorods exhibit good crystal quality. This study has provided a cheap fabrication method for the controlled morphology and good alignment of ZnO nanorods, which is of high demand for enhancing the working performance of optoelectronic devices. PMID:28788336

Optical fiber sensors based on nanostructured coatings fabricated by means of the layer-by-layer electrostatic self-assembly method

NASA Astrophysics Data System (ADS)

Arregui, Francisco J.; Matías, Ignacio R.; Claus, Richard O.

2007-07-01

The Layer-by-Layer Electrostatic Self-Assembly (ESA) method has been successfully used for the design and fabrication of nanostructured materials. More specifically, this technique has been applied for the deposition of thin films on optical fibers with the purpose of fabricating different types of optical fiber sensors. In fact, optical fiber sensors for measuring humidity, temperature, pH, hydrogen peroxide, glucose, volatile organic compounds or even gluten have been already experimentally demonstrated. The versatility of this technique allows the deposition of these sensing coatings on flat substrates and complex geometries as well. For instance, nanoFabry-Perots and microgratings have been formed on cleaved ends of optical fibers (flat surfaces) and also sensing coatings have been built onto long period gratings (cylindrical shape), tapered fiber ends (conical shape), biconically tapered fibers or even the internal side of hollow core fibers. Among the different materials used for the construction of these sensing nanostructured coatings, diverse types such as polymers, inorganic semiconductors, colorimetric indicators, fluorescent dyes, quantum dots or even biological elements as enzymes can be found. This technique opens the door to the fabrication of new types of optical fiber sensors.

Miniaturized Metal (Metal Alloy)/PdO(x)/SiC Hydrogen and Hydrocarbon Gas Sensors

NASA Technical Reports Server (NTRS)

Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

2008-01-01

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO(x)). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600 C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sided sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

Nano-Al{sub 2}O{sub 3} multilayer film deposition on cotton fabrics by layer-by-layer deposition method

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

Ugur, Sule S., E-mail: sule@mmf.sdu.edu.tr; Sariisik, Merih; Aktas, A. Hakan

Highlights: {yields} Cationic charges were created on the cotton fibre surfaces with 2,3-epoxypropyltrimethylammonium chloride. {yields} Al{sub 2}O{sub 3} nanoparticles were deposited on the cotton fabrics by layer-by-layer deposition. {yields} The fabrics deposited with the Al{sub 2}O{sub 3} nanoparticles exhibit better UV-protection and significant flame retardancy properties. {yields} The mechanical properties were improved after surface film deposition. -- Abstract: Al{sub 2}O{sub 3} nanoparticles were used for fabrication of multilayer nanocomposite film deposition on cationic cotton fabrics by electrostatic self-assembly to improve the mechanical, UV-protection and flame retardancy properties of cotton fabrics. Cotton fabric surface was modified with a chemical reaction tomore » build-up cationic charge known as cationization. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy were used to verify the presence of deposited nanolayers. Air permeability, whiteness value, tensile strength, UV-transmittance and Limited Oxygen Index properties of cotton fabrics were analyzed before and after the treatment of Al{sub 2}O{sub 3} nanoparticles by electrostatic self-assemblies. It was proved that the flame retardancy, tensile strength and UV-transmittance of cotton fabrics can be improved by Al{sub 2}O{sub 3} nanoparticle additive through electrostatic self-assembly process.« less

Iron oxide nanoparticle layer templated by polydopamine spheres: a novel scaffold toward hollow-mesoporous magnetic nanoreactors

NASA Astrophysics Data System (ADS)

Huang, Liang; Ao, Lijiao; Xie, Xiaobin; Gao, Guanhui; Foda, Mohamed F.; Su, Wu

2014-12-01

Superparamagnetic iron oxide nanoparticle layers with high packing density and controlled thickness were in situ deposited on metal-affinity organic templates (polydopamine spheres), via one-pot thermal decomposition. The as synthesized hybrid structure served as a facile nano-scaffold toward hollow-mesoporous magnetic carriers, through surfactant-assisted silica encapsulation and its subsequent calcination. Confined but accessible gold nanoparticles were successfully incorporated into these carriers to form a recyclable catalyst, showing quick magnetic response and a large surface area (642.5 m2 g-1). Current nano-reactors exhibit excellent catalytic performance and high stability in reduction of 4-nitrophenol, together with convenient magnetic separability and good reusability. The integration of compact iron oxide nanoparticle layers with programmable polydopamine templates paves the way to fabricate magnetic-response hollow structures, with high permeability and multi-functionality.Superparamagnetic iron oxide nanoparticle layers with high packing density and controlled thickness were in situ deposited on metal-affinity organic templates (polydopamine spheres), via one-pot thermal decomposition. The as synthesized hybrid structure served as a facile nano-scaffold toward hollow-mesoporous magnetic carriers, through surfactant-assisted silica encapsulation and its subsequent calcination. Confined but accessible gold nanoparticles were successfully incorporated into these carriers to form a recyclable catalyst, showing quick magnetic response and a large surface area (642.5 m2 g-1). Current nano-reactors exhibit excellent catalytic performance and high stability in reduction of 4-nitrophenol, together with convenient magnetic separability and good reusability. The integration of compact iron oxide nanoparticle layers with programmable polydopamine templates paves the way to fabricate magnetic-response hollow structures, with high permeability and multi-functionality. Electronic supplementary information (ESI) available: Fig. S1-S5. See DOI: 10.1039/c4nr05931j

Design of matching layers for high-frequency ultrasonic transducers

PubMed Central

Fei, Chunlong; Ma, Jianguo; Chiu, Chi Tat; Williams, Jay A.; Fong, Wayne; Chen, Zeyu; Zhu, BenPeng; Xiong, Rui; Shi, Jing; Hsiai, Tzung K.; Shung, K. Kirk; Zhou, Qifa

2015-01-01

Matching the acoustic impedance of high-frequency (≥100 MHz) ultrasound transducers to an aqueous loading medium remains a challenge for fabricating high-frequency transducers. The traditional matching layer design has been problematic to establish high matching performance given requirements on both specific acoustic impedance and precise thickness. Based on both mass-spring scheme and microwave matching network analysis, we interfaced metal-polymer layers for the matching effects. Both methods hold promises for guiding the metal-polymer matching layer design. A 100 MHz LiNbO3 transducer was fabricated to validate the performance of the both matching layer designs. In the pulse-echo experiment, the transducer echo amplitude increased by 84.4% and its −6dB bandwidth increased from 30.2% to 58.3% comparing to the non-matched condition, demonstrating that the matching layer design method is effective for developing high-frequency ultrasonic transducers. PMID:26445518

Isotropy equilibrium of the double woven fabric with cotton face and wool reverse fibrous compositions

NASA Astrophysics Data System (ADS)

Rahnev, I.; Rimini, G.

2017-10-01

The equilibrium of the masses and the mechanical properties between the warp and the weft is a determining factor for the quality of the woven fabrics. When the fabric has a multi-layered structure and is designed for protective clothing, the uniform distribution of the elastical resistance acquires a paramount importance for the consumer properties. Isotropy in the sense of absolute equalising of the properties between the base and the weft evaluates the achieved optimum cohesion between the weaving threads and directs the weaving cycle settings. The possible variation of the ratio between the elastic modules of the warp and the weft, depending on the weft spacing and the warp tension, is the basic idea of this article.

Novel strip-cast Mg/Al clad sheets with excellent tensile and interfacial bonding properties

PubMed Central

Kim, Jung-Su; Lee, Dong Ho; Jung, Seung-Pill; Lee, Kwang Seok; Kim, Ki Jong; Kim, Hyoung Seop; Lee, Byeong-Joo; Chang, Young Won; Yuh, Junhan; Lee, Sunghak

2016-01-01

In order to broaden industrial applications of Mg alloys, as lightest-weight metal alloys in practical uses, many efforts have been dedicated to manufacture various clad sheets which can complement inherent shortcomings of Mg alloys. Here, we present a new fabrication method of Mg/Al clad sheets by bonding thin Al alloy sheet on to Mg alloy melt during strip casting. In the as-strip-cast Mg/Al clad sheet, homogeneously distributed equi-axed dendrites existed in the Mg alloy side, and two types of thin reaction layers, i.e., γ (Mg17Al12) and β (Mg2Al3) phases, were formed along the Mg/Al interface. After post-treatments (homogenization, warm rolling, and annealing), the interfacial layers were deformed in a sawtooth shape by forming deformation bands in the Mg alloy and interfacial layers, which favorably led to dramatic improvement in tensile and interfacial bonding properties. This work presents new applications to multi-functional lightweight alloy sheets requiring excellent formability, surface quality, and corrosion resistance as well as tensile and interfacial bonding properties. PMID:27245687

Nanotextured thin films for detection of chemicals by surface enhanced Raman scattering

NASA Astrophysics Data System (ADS)

Korivi, Naga; Jiang, Li; Ahmed, Syed; Nujhat, Nabila; Idrees, Mohanad; Rangari, Vijaya

2017-11-01

We report on the development of large area, nanostructured films that function as substrates for surface enhanced Raman scattering (SERS) detection of chemicals. The films are made of polyethylene terephthalate layers partially embedded with multi-walled carbon nanotubes and coated with a thin layer of gold. The films are fabricated by a facile method involving spin-coating, acid dip, and magnetron sputtering. The films perform effectively as SERS substrates when used in the detection of dye pollutants such as Congo red dye, with an enhancement factor of 1.1  ×  106 and a detection limit of 10-7 M which is the lowest reported for CR detection by freestanding SERS film substrates. The films have a long shelf life, and cost US0.20 per cm2 of active area, far less than commercially available SERS substrates. This is the first such work on the use of a polymer layer modified with carbon nanotubes to create a nano-scale texture and arbitrary ‘hot-spots’, contributing to the SERS effect.

Novel strip-cast Mg/Al clad sheets with excellent tensile and interfacial bonding properties.

PubMed

Kim, Jung-Su; Lee, Dong Ho; Jung, Seung-Pill; Lee, Kwang Seok; Kim, Ki Jong; Kim, Hyoung Seop; Lee, Byeong-Joo; Chang, Young Won; Yuh, Junhan; Lee, Sunghak

2016-06-01

In order to broaden industrial applications of Mg alloys, as lightest-weight metal alloys in practical uses, many efforts have been dedicated to manufacture various clad sheets which can complement inherent shortcomings of Mg alloys. Here, we present a new fabrication method of Mg/Al clad sheets by bonding thin Al alloy sheet on to Mg alloy melt during strip casting. In the as-strip-cast Mg/Al clad sheet, homogeneously distributed equi-axed dendrites existed in the Mg alloy side, and two types of thin reaction layers, i.e., γ (Mg17Al12) and β (Mg2Al3) phases, were formed along the Mg/Al interface. After post-treatments (homogenization, warm rolling, and annealing), the interfacial layers were deformed in a sawtooth shape by forming deformation bands in the Mg alloy and interfacial layers, which favorably led to dramatic improvement in tensile and interfacial bonding properties. This work presents new applications to multi-functional lightweight alloy sheets requiring excellent formability, surface quality, and corrosion resistance as well as tensile and interfacial bonding properties.

Alignment of SWNTs by protein-ligand interaction of functionalized magnetic particles under low magnetic fields.

PubMed

Park, Tae Jung; Park, Jong Pil; Lee, Seok Jae; Jung, Dae-Hwan; Ko, Young Koan; Jung, Hee-Tae; Lee, Sang Yup

2011-05-01

Carbon nanotubes (CNTs) have attracted considerable attention for applications using their superior mechanical, thermal and electrical properties. A simple method to controllably align single-walled CNTs (SWNTs) by using magnetic particles embedded with superparamagnetic iron oxide as an accelerator under the magnetic field was developed. The functionalization of SWNTs using biotin, interacted with streptavidin-coupled magnetic particles (micro-to-nano in diameter), and layer-by-layer assembly were performed for the alignment of a particular direction onto the clean silicon and the gold substrate at very low magnetic forces (0.02-0.89 T) at room temperature. The successful alignment of the SWNTs with multi-layer film was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By changing the orientation and location of the substrates, crossed-networks of SWNTs-magnetic particle complex could easily be fabricated. We suggest that this approach, which consists of a combination of biological interaction among streptavidin-biotin and magnetite particles, should be useful for lateral orientation of individual SWNTs with controllable direction.

A method to restrain the charging effect on an insulating substrate in high energy electron beam lithography

NASA Astrophysics Data System (ADS)

Mingyan, Yu; Shirui, Zhao; Yupeng, Jing; Yunbo, Shi; Baoqin, Chen

2014-12-01

Pattern distortions caused by the charging effect should be reduced while using the electron beam lithography process on an insulating substrate. We have developed a novel process by using the SX AR-PC 5000/90.1 solution as a spin-coated conductive layer, to help to fabricate nanoscale patterns of poly-methyl-methacrylate polymer resist on glass for phased array device application. This method can restrain the influence of the charging effect on the insulating substrate effectively. Experimental results show that the novel process can solve the problems of the distortion of resist patterns and electron beam main field stitching error, thus ensuring the accuracy of the stitching and overlay of the electron beam lithography system. The main characteristic of the novel process is that it is compatible to the multi-layer semiconductor process inside a clean room, and is a green process, quite simple, fast, and low cost. It can also provide a broad scope in the device development on insulating the substrate, such as high density biochips, flexible electronics and liquid crystal display screens.

High-throughput preparation of complex multi-scale patterns from block copolymer/homopolymer blend films.

PubMed

Park, Hyungmin; Kim, Jae-Up; Park, Soojin

2012-02-21

A simple, straightforward process for fabricating multi-scale micro- and nanostructured patterns from polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP)/poly(methyl methacrylate) (PMMA) homopolymer in a preferential solvent for PS and PMMA is demonstrated. When the PS-b-P2VP/PMMA blend films were spin-coated onto a silicon wafer, PS-b-P2VP micellar arrays consisting of a PS corona and a P2VP core were formed, while the PMMA macrodomains were isolated, due to the macrophase separation caused by the incompatibility between block copolymer micelles and PMMA homopolymer during the spin-coating process. With an increase of PMMA composition, the size of PMMA macrodomains increased. Moreover, the P2VP blocks have a strong interaction with a native oxide of the surface of the silicon wafer, so that the P2VP wetting layer was first formed during spin-coating, and PS nanoclusters were observed on the PMMA macrodomains beneath. Whereas when a silicon surface was modified with a PS brush layer, the PS nanoclusters underlying PMMA domains were not formed. The multi-scale patterns prepared from copolymer micelle/homopolymer blend films are used as templates for the fabrication of gold nanoparticle arrays by incorporating the gold precursor into the P2VP chains. The combination of nanostructures prepared from block copolymer micellar arrays and macrostructures induced by incompatibility between the copolymer and the homopolymer leads to the formation of complex, multi-scale surface patterns by a simple casting process. This journal is © The Royal Society of Chemistry 2012

An SOI CMOS-Based Multi-Sensor MEMS Chip for Fluidic Applications.

PubMed

Mansoor, Mohtashim; Haneef, Ibraheem; Akhtar, Suhail; Rafiq, Muhammad Aftab; De Luca, Andrea; Ali, Syed Zeeshan; Udrea, Florin

2016-11-04

An SOI CMOS multi-sensor MEMS chip, which can simultaneously measure temperature, pressure and flow rate, has been reported. The multi-sensor chip has been designed keeping in view the requirements of researchers interested in experimental fluid dynamics. The chip contains ten thermodiodes (temperature sensors), a piezoresistive-type pressure sensor and nine hot film-based flow rate sensors fabricated within the oxide layer of the SOI wafers. The silicon dioxide layers with embedded sensors are relieved from the substrate as membranes with the help of a single DRIE step after chip fabrication from a commercial CMOS foundry. Very dense sensor packing per unit area of the chip has been enabled by using technologies/processes like SOI, CMOS and DRIE. Independent apparatuses were used for the characterization of each sensor. With a drive current of 10 µA-0.1 µA, the thermodiodes exhibited sensitivities of 1.41 mV/°C-1.79 mV/°C in the range 20-300 °C. The sensitivity of the pressure sensor was 0.0686 mV/(V excit kPa) with a non-linearity of 0.25% between 0 and 69 kPa above ambient pressure. Packaged in a micro-channel, the flow rate sensor has a linearized sensitivity of 17.3 mV/(L/min) -0.1 in the tested range of 0-4.7 L/min. The multi-sensor chip can be used for simultaneous measurement of fluid pressure, temperature and flow rate in fluidic experiments and aerospace/automotive/biomedical/process industries.

An SOI CMOS-Based Multi-Sensor MEMS Chip for Fluidic Applications †

PubMed Central

Mansoor, Mohtashim; Haneef, Ibraheem; Akhtar, Suhail; Rafiq, Muhammad Aftab; De Luca, Andrea; Ali, Syed Zeeshan; Udrea, Florin

2016-01-01

An SOI CMOS multi-sensor MEMS chip, which can simultaneously measure temperature, pressure and flow rate, has been reported. The multi-sensor chip has been designed keeping in view the requirements of researchers interested in experimental fluid dynamics. The chip contains ten thermodiodes (temperature sensors), a piezoresistive-type pressure sensor and nine hot film-based flow rate sensors fabricated within the oxide layer of the SOI wafers. The silicon dioxide layers with embedded sensors are relieved from the substrate as membranes with the help of a single DRIE step after chip fabrication from a commercial CMOS foundry. Very dense sensor packing per unit area of the chip has been enabled by using technologies/processes like SOI, CMOS and DRIE. Independent apparatuses were used for the characterization of each sensor. With a drive current of 10 µA–0.1 µA, the thermodiodes exhibited sensitivities of 1.41 mV/°C–1.79 mV/°C in the range 20–300 °C. The sensitivity of the pressure sensor was 0.0686 mV/(Vexcit kPa) with a non-linearity of 0.25% between 0 and 69 kPa above ambient pressure. Packaged in a micro-channel, the flow rate sensor has a linearized sensitivity of 17.3 mV/(L/min)−0.1 in the tested range of 0–4.7 L/min. The multi-sensor chip can be used for simultaneous measurement of fluid pressure, temperature and flow rate in fluidic experiments and aerospace/automotive/biomedical/process industries. PMID:27827904

Two-In-One Method for Graphene Transfer: Simplified Fabrication Process for Organic Light-Emitting Diodes.

PubMed

Liu, Lihui; Shang, Wenjuan; Han, Chao; Zhang, Qing; Yao, Yao; Ma, Xiaoqian; Wang, Minghao; Yu, Hongtao; Duan, Yu; Sun, Jie; Chen, Shufen; Huang, Wei

2018-02-28

Graphene as one of the most promising transparent electrode materials has been successfully applied in organic light-emitting diodes (OLEDs). However, traditional poly(methyl methacrylate) (PMMA) transfer method usually results in hardly removed polymeric residues on the graphene surface, which induces unwanted leakage current, poor diode behavior, and even device failure. In this work, we proposed a facile and efficient two-in-one method to obtain clean graphene and fabricate OLEDs, in which the poly(9,9-di-n-octylfluorene-alt-(1,4-phenylene-(4-sec-butylphenyl)imino)-1,4-phenylene) (TFB) layer was inserted between the graphene and PMMA film both as a protector during the graphene transfer and a hole-injection layer in OLEDs. Finally, green OLED devices were successfully fabricated on the PMMA-free graphene/TFB film, and the device luminous efficiency was increased from 64.8 to 74.5 cd/A by using the two-in-one method. Therefore, the proposed two-in-one graphene transfer method realizes a high-efficient graphene transfer and device fabrication process, which is also compatible with the roll-to-roll manufacturing. It is expected that this work can enlighten the design and fabrication of the graphene-based optoelectronic devices.

Influence of substrates and rutile seed layers on the assembly of hydrothermally grown rutile TiO2 nanorod arrays

NASA Astrophysics Data System (ADS)

Kalb, Julian; Dorman, James A.; Folger, Alena; Gerigk, Melanie; Knittel, Vanessa; Plüisch, Claudia S.; Trepka, Bastian; Lehr, Daniela; Chua, Emily; Goodge, Berit H.; Wittemann, Alexander; Scheu, Christina; Polarz, Sebastian; Schmidt-Mende, Lukas

2018-07-01

Rutile TiO2 nanorod arrays (NRAs) are applicable in various prospective technologies. Hydrothermal methods present a simple technique to fabricate such NRAs. In this report, we present the fabrication of seed layers for the hydrothermal growth of rutile TiO2 nanorods via sputter deposition, electron-beam evaporation, and sol-gel method and study the influence of each on the growth behavior. To satisfy the requirements of numerous applications, p-type silicon, platinum, levitating carbon membranes, a template made of polystyrene spheres, and commercial fluorine tin oxide (FTO) were employed as substrates. We document the structural properties of the TiO2 seed layers and describe the relationship between the characteristics of the seed crystals, the growth evolution, and the appearance of as-grown nanorods. Various growth stages of rutile TiO2 nanorods are compared depending on whether they are grown on polycrystalline TiO2 or FTO seed layers. In both cases, a homogenous TiO2 bottom layer is formed at the seed layer/substrate interface, which is essential for electronic applications such as hybrid solar cells. Detached NRAs illustrate the effect of rutile FTO and TiO2 on the porosity of this bottom layer. Further details about the formation process of this layer are obtained from the growth on confined seed layers fabricated by electron-beam lithography.

Tailoring graphene layer-to-layer growth

NASA Astrophysics Data System (ADS)

Li, Yongtao; Wu, Bin; Guo, Wei; Wang, Lifeng; Li, Jingbo; Liu, Yunqi

2017-06-01

A layered material grown between a substrate and the upper layer involves complex interactions and a confined reaction space, representing an unusual growth mode. Here, we show multi-layer graphene domains grown on liquid or solid Cu by the chemical vapor deposition method via this ‘double-substrate’ mode. We demonstrate the interlayer-induced coupling effect on the twist angle in bi- and multi-layer graphene. We discover dramatic growth disunity for different graphene layers, which is explained by the ideas of a chemical ‘gate’ and a material transport process within a confined space. These key results lead to a consistent framework for understanding the dynamic evolution of multi-layered graphene flakes and tailoring the layer-to-layer growth for practical applications.

Fabrication process for polymer PLC platforms with V-grooves for passive alignment

NASA Astrophysics Data System (ADS)

Park, Suntak; Lee, Jong-Moo; Ahn, Joon Tae; Baek, Yong-Soon

2005-12-01

A method for polymer planar lightwave circuit (PLC) devices fabricated on a substrate with V-grooves is developed for passive alignment of an optical fiber to a polymer waveguide. In order to minimize thickness nonuniformity of polymer layers caused by the V-grooves, dry film resist (DFR) is used. The V-grooves are covered with the DFR before the polymer layers are spin-coated on the substrate. The DFR prevents the polymer from being filled in the V-grooves as well as from being spin-coated nonuniformly on the substrate. This process provides a simple and cost-effective fabrication method of polymer PLCs or platforms for passive alignment.

Development of Eddy Current Techniques for Detection of Deep Fatigue Cracks in Multi-Layer Airframe Components

NASA Technical Reports Server (NTRS)

Wincheski, Russell A.

2008-01-01

Thick, multi-layer aluminum structure has been widely used in aircraft design in critical wing splice areas. The multi-layer structure generally consists of three or four aluminum layers with different geometry and varying thickness, which are held together with fasteners. The detection of cracks under fasteners with ultrasonic techniques in subsurface layers away from the skin is impeded primarily by interlayer bonds and faying sealant condition. Further, assessment of such sealant condition is extremely challenging in terms of complexity of structure, limited access, and inspection cost. Although Eddy current techniques can be applied on in-service aircraft from the exterior of the skin without knowing sealant condition, the current eddy current techniques are not able to detect defects with wanted sensitivity. In this work a series of low frequency eddy current probes have been designed, fabricated and tested for this application. A probe design incorporating a shielded magnetic field sensor concentrically located in the interior of a drive coil has been employed to enable a localized deep diffusion of the electromagnetic field into the part under test. Due to the required low frequency inspections, probes have been testing using a variety of magnetic field sensors (pickup coil, giant magneto-resistive, anisotropic magneto-resistive, and spin-dependent tunneling). The probe designs as well as capabilities based upon a target inspection for sub-layer cracking in an airframe wing spar joint is presented.

Fabrication of wedged multilayer Laue lenses

DOE PAGES

Prasciolu, M.; Leontowich, A. F. G.; Krzywinski, J.; ...

2015-01-01

We present a new method to fabricate wedged multilayer Laue lenses, in which the angle of diffracting layers smoothly varies in the lens to achieve optimum diffracting efficiency across the entire pupil of the lens. This was achieved by depositing a multilayer onto a flat substrate placed in the penumbra of a straight-edge mask. The distance between the mask and the substrate was calibrated and the multilayer Laue lens was cut in a position where the varying layer thickness and the varying layer tilt simultaneously satisfy the Fresnel zone plate condition and Bragg’s law for all layers in the stack.more » This method can be used to extend the achievable numerical aperture of multilayer Laue lenses to reach considerably smaller focal spot sizes than achievable with lenses composed of parallel layers.« less

Optofluidic fabrication for 3D-shaped particles

NASA Astrophysics Data System (ADS)

Paulsen, Kevin S.; di Carlo, Dino; Chung, Aram J.

2015-04-01

Complex three-dimensional (3D)-shaped particles could play unique roles in biotechnology, structural mechanics and self-assembly. Current methods of fabricating 3D-shaped particles such as 3D printing, injection moulding or photolithography are limited because of low-resolution, low-throughput or complicated/expensive procedures. Here, we present a novel method called optofluidic fabrication for the generation of complex 3D-shaped polymer particles based on two coupled processes: inertial flow shaping and ultraviolet (UV) light polymerization. Pillars within fluidic platforms are used to deterministically deform photosensitive precursor fluid streams. The channels are then illuminated with patterned UV light to polymerize the photosensitive fluid, creating particles with multi-scale 3D geometries. The fundamental advantages of optofluidic fabrication include high-resolution, multi-scalability, dynamic tunability, simple operation and great potential for bulk fabrication with full automation. Through different combinations of pillar configurations, flow rates and UV light patterns, an infinite set of 3D-shaped particles is available, and a variety are demonstrated.

CVD synthesis of large-area, highly crystalline MoSe2 atomic layers on diverse substrates and application to photodetectors.

PubMed

Xia, Jing; Huang, Xing; Liu, Ling-Zhi; Wang, Meng; Wang, Lei; Huang, Ben; Zhu, Dan-Dan; Li, Jun-Jie; Gu, Chang-Zhi; Meng, Xiang-Min

2014-08-07

Synthesis of large-area, atomically thin transition metal dichalcogenides (TMDs) on diverse substrates is of central importance for the large-scale fabrication of flexible devices and heterojunction-based devices. In this work, we successfully synthesized a large area of highly-crystalline MoSe2 atomic layers on SiO2/Si, mica and Si substrates using a simple chemical vapour deposition (CVD) method at atmospheric pressure. Atomic force microscopy (AFM) and Raman spectroscopy reveal that the as-grown ultrathin MoSe2 layers change from a single layer to a few layers. Photoluminescence (PL) spectroscopy demonstrates that while the multi-layer MoSe2 shows weak emission peaks, the monolayer has a much stronger emission peak at ∼ 1.56 eV, indicating the transition from an indirect to a direct bandgap. Transmission electron microscopy (TEM) analysis confirms the single-crystallinity of MoSe2 layers with a hexagonal structure. In addition, the photoresponse performance of photodetectors based on MoSe2 monolayer was studied for the first time. The devices exhibit a rapid response of ∼ 60 ms and a good photoresponsivity of ∼ 13 mA/W (using a 532 nm laser at an intensity of 1 mW mm(-2) and a bias of 10 V), suggesting that MoSe2 monolayer is a promising material for photodetection applications.

Multi-clad black display panel

DOEpatents

Veligdan, James T.; Biscardi, Cyrus; Brewster, Calvin

2002-01-01

A multi-clad black display panel, and a method of making a multi-clad black display panel, are disclosed, wherein a plurality of waveguides, each of which includes a light-transmissive core placed between an opposing pair of transparent cladding layers and a black layer disposed between transparent cladding layers, are stacked together and sawed at an angle to produce a wedge-shaped optical panel having an inlet face and an outlet face.

Stretchable multilayer self-aligned interconnects fabricated using excimer laser photoablation and in situ masking

NASA Astrophysics Data System (ADS)

Lin, Kevin L.; Jain, Kanti

2009-02-01

Stretchable interconnects are essential to large-area flexible circuits and large-area sensor array systems, and they play an important role towards the realization of the realm of systems which include wearable electronics, sensor arrays for structural health monitoring, and sensor skins for tactile feedback. These interconnects must be reliable and robust for viability, and must be flexible, stretchable, and conformable to non-planar surfaces. This research describes the design, modeling, fabrication, and testing of stretchable interconnects on polymer substrates using metal patterns both as functional interconnect layers and as in-situ masks for excimer laser photoablation. Excimer laser photoablation is often used for patterning of polymers and thin-film metals. The fluences for photoablation of polymers are generally much lower than the threshold fluence for removal or damage of high-thermallyconductive metals; thus, metal thin films can be used as in-situ masks for polymers if the proper fluence is used. Selfaligned single-layer and multi-layer interconnects of various designs (rectilinear and 'meandering') have been fabricated, and certain 'meandering' interconnect designs can be stretched up to 50% uniaxially while maintaining good electrical conductivity and structural integrity. These results are compared with Finite Element Analysis (FEA) models and are observed to be in good accordance with them. This fabrication approach eliminates masks and microfabrication processing steps as compared to traditional fabrication approaches; furthermore, this technology is scalable for large-area sensor arrays and electronic circuits, adaptable for a variety of materials and interconnects designs, and compatible with MEMS-based capacitive sensor technology.

Flexible ITO-free organic solar cells applying aqueous solution-processed V2O5 hole transport layer: An outdoor stability study

NASA Astrophysics Data System (ADS)

Lima, F. Anderson S.; Beliatis, Michail J.; Roth, Bérenger; Andersen, Thomas R.; Bortoti, Andressa; Reyna, Yegraf; Castro, Eryza; Vasconcelos, Igor F.; Gevorgyan, Suren A.; Krebs, Frederik C.; Lira-Cantu, Mónica

2016-02-01

Solution processable semiconductor oxides have opened a new paradigm for the enhancement of the lifetime of thin film solar cells. Their fabrication by low-cost and environmentally friendly solution-processable methods makes them ideal barrier (hole and electron) transport layers. In this work, we fabricate flexible ITO-free organic solar cells (OPV) by printing methods applying an aqueous solution-processed V2O5 as the hole transport layer (HTL) and compared them to devices applying PEDOT:PSS. The transparent conducting electrode was PET/Ag/PEDOT/ZnO, and the OPV configuration was PET/Ag/PEDOT/ZnO/P3HT:PC60BM/HTL/Ag. Outdoor stability analyses carried out for more than 900 h revealed higher stability for devices fabricated with the aqueous solution-processed V2O5.

Fabrication of nano-gap electrode arrays by the construction and selective chemical etching of nano-crosswire stacks

NASA Technical Reports Server (NTRS)

Prokopuk, Nicholas (Inventor); Son, Kyung-Ah (Inventor)

2008-01-01

Methods of fabricating nano-gap electrode structures in array configurations, and the structures so produced. The fabrication method involves depositing first and second pluralities of electrodes comprising nanowires using processes such as lithography, deposition of metals, lift-off processes, and chemical etching that can be performed using conventional processing tools applicable to electronic materials processing. The gap spacing in the nano-gap electrode array is defined by the thickness of a sacrificial spacer layer that is deposited between the first and second pluralities of electrodes. The sacrificial spacer layer is removed by etching, thereby leaving a structure in which the distance between pairs of electrodes is substantially equal to the thickness of the sacrificial spacer layer. Electrode arrays with gaps measured in units of nanometers are produced. In one embodiment, the first and second pluralities of electrodes are aligned in mutually orthogonal orientations.

Methods for the fabrication of thermally stable magnetic tunnel junctions

DOEpatents

Chang, Y Austin [Middleton, WI; Yang, Jianhua J [Madison, WI; Ladwig, Peter F [Hutchinson, MN

2009-08-25

Magnetic tunnel junctions and method for making the magnetic tunnel junctions are provided. The magnetic tunnel junctions are characterized by a tunnel barrier oxide layer sandwiched between two ferromagnetic layers. The methods used to fabricate the magnetic tunnel junctions are capable of completely and selectively oxidizing a tunnel junction precursor material using an oxidizing gas containing a mixture of gases to provide a tunnel junction oxide without oxidizing the adjacent ferromagnetic materials. In some embodiments the gas mixture is a mixture of CO and CO.sub.2 or a mixture of H.sub.2 and H.sub.2O.

Arsenic sulfide layers for dielectric reflection mirrors prepared from solution

NASA Astrophysics Data System (ADS)

Matějec, Vlastimil; Pedlikova, Jitka; BartoÅ, Ivo; Podrazký, Ondřej

2017-12-01

Chalcogenide materials due to high refractive indices, transparency in the mid-IR spectral region, nonlinear refractive indices, etc, have been employed as fibers and films in different photonic devices such as light amplifiers, optical regenerators, broadband radiation sources. Chalcogenide films can be prepared by physical methods as well as by solution-based techniques in which solutions of chalcogenides in amines are used. This paper presents results on the solution-based fabrication and optical characterization of single arsenic sulfide layers and multilayer stacks containing As2S3 layers together with porous silica layers coated on planar and fiber-optic substrates. Input As2S3 solutions for the layer fabrications were prepared by dissolving As2S3 powder in n-propylamine in a concentration of 0.50 mol/l. These solutions were applied on glass slides by dip-coating method and obtained layers were thermally treated in vacuum at temperatures up to 180 °C. Similar procedure was used for As2S3 layers in multilayer stacks. Such stacks were fabricated by repeating the application of one porous silica layer prepared by the sol-gel method and one As2S3 layer onto glass slides or silica fibers (a diameter of 0.3 mm) by using the dip-coating method. It has been found that the curing process of the applied layers has to be carefully controlled in order to obtain stacks with three pairs of such layers. Single arsenic and porous silica layers were characterized by optical microscopy, and by measuring their transmission spectra in a range of 200-2500 nm. Thicknesses and refractive indices were estimated from the spectra. Transmission spectra of planar multilayer stacks were measured, too. Interference bands have been determined from optical measurements on the multilayer stacks with a minimum transmittance of about 50% which indicates the possibility of using such stacks as reflecting mirrors.

Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes

PubMed Central

Ávila-Orta, Carlos A.; Quiñones-Jurado, Zoe V.; Waldo-Mendoza, Miguel A.; Rivera-Paz, Erika A.; Cruz-Delgado, Víctor J.; Mata-Padilla, José M.; González-Morones, Pablo; Ziolo, Ronald F.

2015-01-01

Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods. PMID:28793686

Flexural Properties of PLA Components Under Various Test Condition Manufactured by 3D Printer

NASA Astrophysics Data System (ADS)

Jaya Christiyan, K. G.; Chandrasekhar, U.; Venkateswarlu, K.

2018-06-01

Rapid Prototyping (RP) technologies have emerged as a fabrication method to obtain engineering components in the resent past. Desktop 3D printing, also referred as an additive layer manufacturing technology is a powerful method of RP technique that can fabricate 3 dimensional engineering components. In this method, 3D digital data is converted into real product. In the present investigation, Polylactic Acid (PLA) was considered as a starting material. Flexural strength of PLA material was evaluated using 3-point bend test, as per ASTM D790 standard. Specimens with flat (0°) and vertical (90°) orientation were considered. Moreover, layer thicknesses of 0.2, 0.25, and 0.3 mm were considered. To fabricate these specimens, printing speed of 38 and 52 mm/s was maintained. Nozzle diameter of 0.4 mm with 40 % of infill density were used. Based on the experimental results, it was observed that 0° orientation, 38 mm/s printing speed, and 0.2 mm layer thickness resulted maximum flexural strength, as compared to all other specimens. The improved flexural strength was due to the lower layer thickness (0.2 mm) specimens, as compared with other specimens made of 0.25 and 0.30 mm layer thicknesses. It was concluded that flexural strength properties were greatly influenced by lower the layer thickness, printing speed, and orientation.

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.

Steering air bubbles with an add-on vacuum layer for biopolymer membrane biofabrication in PDMS microfluidics.

PubMed

Pham, Phu; Vo, Thanh; Luo, Xiaolong

2017-01-17

Membrane functionality is crucial in microfluidics for realizing operations such as filtration, separation, concentration, signaling among cells and gradient generation. Currently, common methods often sandwich commercially available membranes in multi-layer devices, or use photopolymerization or temperature-induced gelation to fabricate membrane structures in one-layer devices. Biofabrication offers an alternative to forming membrane structures with biomimetic materials and mechanisms in mild conditions. We have recently developed a biofabrication strategy to form parallel biopolymer membranes in gas-permeable polydimethylsiloxane (PDMS) microfluidic devices, which used positive pressure to dissipate air bubbles through PDMS to initiate membrane formation but required careful pressure balancing between two flows. Here, we report a technical innovation by simply placing as needed an add-on PDMS vacuum layer on PDMS microfluidic devices to dissipate air bubbles and guide the biofabrication of biopolymer membranes. Vacuuming through PDMS was simply achieved by either withdrawing a syringe or releasing a squeezed nasal aspirator. Upon vacuuming, air bubbles dissipated within minutes, membranes were effortlessly formed, and the add-on vacuum layer can be removed. Subsequent membrane growth could be robustly controlled with the flows and pH of solutions. This new process is user-friendly and has achieved a 100% success rate in more than 200 trials in membrane biofabrication.

Wearable Fabrics with Self-Branched Bimetallic Layered Double Hydroxide Coaxial Nanostructures for Hybrid Supercapacitors.

PubMed

Nagaraju, Goli; Chandra Sekhar, S; Krishna Bharat, L; Yu, Jae Su

2017-11-28

We report a flexible battery-type electrode based on binder-free nickel cobalt layered double hydroxide nanosheets adhered to nickel cobalt layered double hydroxide nanoflake arrays on nickel fabric (NC LDH NFAs@NSs/Ni fabric) using facile and eco-friendly synthesis methods. Herein, we utilized discarded polyester fabric as a cost-effective substrate for in situ electroless deposition of Ni, which exhibited good flexibility, light weight, and high conductivity. Subsequently, the vertically aligned NC LDH NFAs were grown on Ni fabric by means of a hot-air oven-based method, and fluffy-like NC LDH NS branches are further decorated on NC LDH NFAs by a simple electrochemical deposition method. The as-prepared core-shell-like nanoarchitectures improve the specific surface area and electrochemical activity, which provides the ideal pathways for electrolyte diffusion and charge transportation. When the electrochemical performance was tested in 1 M KOH aqueous solution, the core-shell-like NC LDH NFAs@NSs/Ni fabric electrode liberated a maximum areal capacity of 536.96 μAh/cm 2 at a current density of 2 mA/cm 2 and excellent rate capability of 78.3% at 30 mA/cm 2 (420.5 μAh/cm 2 ) with a good cycling stability. Moreover, a fabric-based hybrid supercapacitor (SC) was assembled, which achieves a stable operational potential window of 1.6 V, a large areal capacitance of 1147.23 mF/cm 2 at 3 mA/cm 2 , and a high energy density of 0.392 mWh/cm 2 at a power density of 2.353 mW/cm 2 . Utilizing such high energy storage abilities and flexible properties, the fabricated hybrid SC operated the wearable digital watch and electric motor fan for real-time applications.

Method for fabricating photovoltaic device having improved short wavelength photoresponse

DOEpatents

Catalano, Anthony W.

1989-07-04

Amorphous p-i-n silicon photovoltaic cells with improved short wavelength photoresponse are fabricated with reduced p-dopant contamination at the p/i interface. Residual p-dopants are removed by flushing the deposition chamber with a gaseous mixture capable of reacting with excess doping contaminants prior to the deposition of the i-layer and subsequent to the deposition of the p-layer.

Fabrication and stabilization of silicon-based photonic crystals with tuned morphology for multi-band optical filtering

NASA Astrophysics Data System (ADS)

Salem, Mohamed Shaker; Abdelaleem, Asmaa Mohamed; El-Gamal, Abear Abdullah; Amin, Mohamed

2017-01-01

One-dimensional silicon-based photonic crystals are formed by the electrochemical anodization of silicon substrates in hydrofluoric acid-based solution using an appropriate current density profile. In order to create a multi-band optical filter, two fabrication approaches are compared and discussed. The first approach utilizes a current profile composed of a linear combination of sinusoidal current waveforms having different frequencies. The individual frequency of the waveform maps to a characteristic stop band in the reflectance spectrum. The stopbands of the optical filter created by the second approach, on the other hand, are controlled by stacking multiple porous silicon rugate multilayers having different fabrication conditions. The morphology of the resulting optical filters is tuned by controlling the electrolyte composition and the type of the silicon substrate. The reduction of sidelobes arising from the interference in the multilayers is observed by applying an index matching current profile to the anodizing current waveform. In order to stabilize the resulting optical filters against natural oxidation, atomic layer deposition of silicon dioxide on the pore wall is employed.

A novel multi-level IC-compatible surface microfabrication technology for MEMS with independently controlled lateral and vertical submicron transduction gaps

NASA Astrophysics Data System (ADS)

Cicek, Paul-Vahe; Elsayed, Mohannad; Nabki, Frederic; El-Gamal, Mourad

2017-11-01

An above-IC compatible multi-level MEMS surface microfabrication technology based on a silicon carbide structural layer is presented. The fabrication process flow provides optimal electrostatic transduction by allowing the creation of independently controlled submicron vertical and lateral gaps without the need for high resolution lithography. Adopting silicon carbide as the structural material, the technology ensures material, chemical and thermal compatibility with modern semiconductor nodes, reporting the lowest peak processing temperature (i.e. 200 °C) of all comparable works. This makes this process ideally suited for integrating capacitive-based MEMS directly above standard CMOS substrates. Process flow design and optimization are presented in the context of bulk-mode disk resonators, devices that are shown to exhibit improved performance with respect to previous generation flexural beam resonators, and that represent relatively complex MEMS structures. The impact of impending improvements to the fabrication technology is discussed.

Multi-heteroatom doped carbon coated Na3V2(PO4)3 derived from ionic liquids.

PubMed

Zhang, Lu-Lu; Zhou, Ying-Xian; Li, Tao; Ma, Di; Yang, Xue-Lin

2018-03-28

Multi-heteroatom (N, S and F) doped carbon coated Na 3 V 2 (PO 4 ) 3 (labeled as NVP/C-ILs) derived from an ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM]TF2N) has been successfully fabricated. The as-prepared Na 3 V 2 (PO 4 ) 3 particles are well dispersed and closely coated with a multi-heteroatom (N, S and F) doped carbon layer. As a cathode for sodium-ion batteries, the NVP/C-ILs electrode exhibits high reversible specific capacity (117.5 mA h g -1 at 1C), superior rate performance (93.4 mA h g -1 at 10C) and excellent cycling stability (∼95% capacity retention ratio at 10C over 1000 cycles). The impressive electrochemical performance of NVP/C-ILs can be attributed to effectively conductive networks for electrons and Na + ions induced by a joint effect of N, S and F doping on carbon. The use of multi-heteroatom doped carbon coated Na 3 V 2 (PO 4 ) 3 provides a facile and effective strategy for the fabrication of high performance electrode materials with low intrinsic electrical conductivity.

A pentacene monolayer trapped between graphene and a substrate.

PubMed

Zhang, Qicheng; Peng, Boyu; Chan, Paddy Kwok Leung; Luo, Zhengtang

2015-09-21

A self-assembled pentacene monolayer can be fabricated between the solid-solid interface of few-layered graphene (FLG) and the mica substrate, through a diffusion-spreading method. By utilizing a transfer method that allows us to sandwich pentacene between graphene and mica, followed by controlled annealing, we enabled the diffused pentacene to be trapped in the interfaces and led to the formation of a stable monolayer. We found that the formation of a monolayer is kinetically favored by using a 2D Ising lattice gas model for pentacene trapped between the graphene-substrate interfaces. This kinetic Monte Carlo simulation results indicate that, due to the graphene substrate enclosure, the spreading of the first layer proceeds faster than the second layer, as the kinetics favors the filling of voids by molecules from the second layer. This graphene assisted monolayer assembly method provides a new avenue for the fabrication of two-dimensional monolayer structures.

Further study of inversion layer MIS solar cells

NASA Technical Reports Server (NTRS)

Ho, Fat Duen

1992-01-01

Many inversion layer metal-insulator-semiconductor (IL/MIS) solar cells have been fabricated. As of today, the best cell fabricated by us has a 9.138 percent AMO efficiency, with FF = 0.641, V(sub OC) = 0.557 V, and I(sub SC) = 26.9 micro A. Efforts made for fabricating an IL/MOS solar cell with reasonable efficiencies are reported. The more accurate control of the thickness of the thin layer of oxide between aluminum and silicon of the MIS contacts has been achieved by using two different process methods. Comparison of these two different thin oxide processings is reported. The effects of annealing time of the sample are discussed. The range of the resistivity of the substrates used in the IL cell fabrication is experimentally estimated. Theoretical study of the MIS contacts under dark conditions is addressed.

A Liquid Optical Phase Shifter with an Embedded Electrowetting Actuator

PubMed Central

Ashtiani, Alireza Ousati; Jiang, Hongrui

2017-01-01

We demonstrate an electrowetting-based liquid optical phase shifter. The phase shifter consists of two immiscible liquid layers with different refractive indices. Sandwiched between the two liquids is a rigid membrane that moves freely along the optical axis and supported by a compliant surround. When applied with a pressure, the thicknesses of both liquid layers change, which induces a difference in optical path, resulting in a phase shift. A miniaturized electrowetting-based actuator is used to produce hydraulic pressure. A multi-layered SU8 bonded structure was fabricated. A phase shift of 171° was observed when the device was incorporated in a Mach-Zehnder interferometer and driven with 100 V. PMID:29038640

Switchable vanadium dioxide (VO2) metamaterials fabricated from tungsten doped vanadia-based colloidal nanocrystals

NASA Astrophysics Data System (ADS)

Paik, Taejong; Hong, Sung-Hoon; Gordon, Thomas; Gaulding, Ashley; Kagan, Cherie; Murray, Christopher

2013-03-01

We report the fabrication of thermochromic VO2-based metamaterials using solution-processable colloidal nanocrystals. Vanadium-based nanoparticles are prepared through a non-hydrolytic reaction, resulting in stable colloidal dispersions in solution. Thermochromic nanocrystalline VO2 thin-films are prepared via rapid thermal annealing of colloidal nanoparticles coated on a variety of substrates. Nanostructured VO2 can be patterned over large areas by nanoimprint lithography. Precise control of tungsten (W) doping concentration in colloidal nanoparticles enables tuning of the phase transition temperature of the nanocrystalline VO2 thin-films. W-doped VO2 films display a sharp temperature dependent phase transition, similar to the undoped VO2 film, but at lower temperatures tunable with the doping level. By sequential coating of doped VO2 with different doping concentrations, we fabricate ?smart? multi-layered VO2 films displaying multiple phase transition temperatures within a single structure, allowing for dynamic modulation of the metal-dielectric layered structure. The optical properties programmed into the layered structure are switchable with temperature, which provides additional degrees of freedom to design tunable optical metamaterials. This work is supported by the US Office of Naval Research Multidisciplinary University Research Initiative (MURI) program grant number ONR-N00014-10-1-0942.

Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

NASA Technical Reports Server (NTRS)

Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

2011-01-01

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x ). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

NASA Technical Reports Server (NTRS)

Xu, Jennifer C. (Inventor); Hunter, Gary W. (Inventor); Lukco, Dorothy (Inventor)

2008-01-01

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps

DOEpatents

Wanlass, Mark W [Golden, CO; Mascarenhas, Angelo [Lakewood, CO

2012-05-08

Modeling a monolithic, multi-bandgap, tandem, solar photovoltaic converter or thermophotovoltaic converter by constraining the bandgap value for the bottom subcell to no less than a particular value produces an optimum combination of subcell bandgaps that provide theoretical energy conversion efficiencies nearly as good as unconstrained maximum theoretical conversion efficiency models, but which are more conducive to actual fabrication to achieve such conversion efficiencies than unconstrained model optimum bandgap combinations. Achieving such constrained or unconstrained optimum bandgap combinations includes growth of a graded layer transition from larger lattice constant on the parent substrate to a smaller lattice constant to accommodate higher bandgap upper subcells and at least one graded layer that transitions back to a larger lattice constant to accommodate lower bandgap lower subcells and to counter-strain the epistructure to mitigate epistructure bowing.

Relationship between open-circuit voltage in Cu(In,Ga)Se{sub 2} solar cell and peak position of (220/204) preferred orientation near its absorber surface

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

Chantana, J., E-mail: jakapan@fc.ritsumei.ac.jp; Minemoto, T.; Watanabe, T.

2013-11-25

Cu(In,Ga)Se{sub 2} (CIGS) absorbers with various Ga/III, Ga/(In+Ga), profiles are prepared by the so-called “multi-layer precursor method” using multi-layer co-evaporation of material sources. It is revealed that open-circuit voltage (V{sub OC}) of CIGS solar cell is primarily dependent on averaged Ga/III near the surface of its absorber. This averaged Ga/III is well predicted by peak position of (220/204) preferred orientation of CIGS film near its surface investigated by glancing-incidence X-ray diffraction with 0.1° incident angle. Finally, the peak position of (220/204) preferred orientation is proposed as a measure of V{sub OC} before solar cell fabrication.

Optically transduced MEMS magnetometer

DOEpatents

Nielson, Gregory N; Langlois, Eric

2014-03-18

MEMS magnetometers with optically transduced resonator displacement are described herein. Improved sensitivity, crosstalk reduction, and extended dynamic range may be achieved with devices including a deflectable resonator suspended from the support, a first grating extending from the support and disposed over the resonator, a pair of drive electrodes to drive an alternating current through the resonator, and a second grating in the resonator overlapping the first grating to form a multi-layer grating having apertures that vary dimensionally in response to deflection occurring as the resonator mechanically resonates in a plane parallel to the first grating in the presence of a magnetic field as a function of the Lorentz force resulting from the alternating current. A plurality of such multi-layer gratings may be disposed across a length of the resonator to provide greater dynamic range and/or accommodate fabrication tolerances.

Aqueous Solution-Phase Selenized CuIn(S,Se)2 Thin Film Solar Cells Annealed under Inert Atmosphere.

PubMed

Oh, Yunjung; Yang, Wooseok; Kim, Jimin; Woo, Kyoohee; Moon, Jooho

2015-10-14

A nonvacuum solution-based approach can potentially be used to realize low cost, roll-to-roll fabrication of chalcopyrite CuIn(S,Se)2 (CISSe) thin film solar cells. However, most solution-based fabrication methods involve highly toxic solvents and inevitably require sulfurization and/or postselenization with hazardous H2S/H2Se gases. Herein, we introduce novel aqueous-based Cu-In-S and Se inks that contain an amine additive for producing a high-quality absorber layer. CISSe films were fabricated by simple deposition of Cu-In-S ink and Se ink followed by annealing under an inert atmosphere. Compositional and phase analyses confirmed that our simple aqueous ink-based method facilitated in-site selenization of the CIS layer. In addition, we investigated the molecular structures of our aqueous inks to determine how crystalline chalcopyrite absorber layers developed without sulfurization and/or postselenization. CISSe thin film solar cells annealed at 550 °C exhibited an efficiency of 4.55% under AM 1.5 illumination. The low-cost, nonvacuum method to deposit chalcopyrite absorber layers described here allows for safe and simple processing of thin film solar cells.

Fabrication of tungsten wire reinforced nickel-base alloy composites

NASA Technical Reports Server (NTRS)

Brentnall, W. D.; Toth, I. J.

1974-01-01

Fabrication methods for tungsten fiber reinforced nickel-base superalloy composites were investigated. Three matrix alloys in pre-alloyed powder or rolled sheet form were evaluated in terms of fabricability into composite monotape and multi-ply forms. The utility of monotapes for fabricating more complex shapes was demonstrated. Preliminary 1093C (2000F) stress rupture tests indicated that efficient utilization of fiber strength was achieved in composites fabricated by diffusion bonding processes. The fabrication of thermal fatigue specimens is also described.

A general strategy to fabricate photonic crystal heterostructure with Programmed photonic stopband.

PubMed

Zhang, Lijing; Liu, Bofan; Wang, Jie; Tao, Shengyang; Yan, Qingfeng

2018-01-01

In this paper, we present a general fabrication strategy to achieve the structure control and the flexible photonic stop band regulation of (2+1) D photonic crystal heterostructures (PCHs) by layer-by-layer depositing the annealed colloidal crystal monolayers of different sphere size. The optical properties of the resulting (2+1) DPCHs with different lattice constants were systematically studied and a universal photonic stopband variation rule was proposed, which makes it possible to program any kind of stopband structure as required, such as dual- or multi-stopbands PCH and ultra-wide stopband PCH. Furthermore, PCH with dual-stopbands overlapping the excitation wavelength (E) and emission wavelength(F) of Ru complex was fabricated by finely manipulating the spheres' diameter of colloidal monolayers. And an additional 2-fold fluorescence enhancement in comparison to that on the single stopband sample was achieved. This strategy affords new opportunities for delicate engineering the photonic behaviour of PCH, and also is of great significance for the practical application based on their bandgap property. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of advanced second-generation micromirror devices fabricated in a four-level planarized surface-micromachined polycrystalline silicon process

NASA Astrophysics Data System (ADS)

Michalicek, M. Adrian; Comtois, John H.; Schriner, Heather K.

1998-04-01

This paper describes the design and characterization of several types of micromirror devices to include process capabilities, device modeling, and test data resulting in deflection versus applied potential curves and surface contour measurements. These devices are the first to be fabricated in the state-of-the-art four-level planarized polysilicon process available at Sandia National Laboratories known as the Sandia Ultra-planar Multi-level MEMS Technology. This enabling process permits the development of micromirror devices with near-ideal characteristics which have previously been unrealizable in standard three-layer polysilicon processes. This paper describes such characteristics which have previously been unrealizable in standard three-layer polysilicon processes. This paper describes such characteristics as elevated address electrodes, various address wiring techniques, planarized mirror surfaces suing Chemical Mechanical Polishing, unique post-process metallization, and the best active surface area to date.

Production of dissolvable microneedles using an atomised spray process: effect of microneedle composition on skin penetration.

PubMed

McGrath, Marie G; Vucen, Sonja; Vrdoljak, Anto; Kelly, Adam; O'Mahony, Conor; Crean, Abina M; Moore, Anne

2014-02-01

Dissolvable microneedles offer an attractive delivery system for transdermal drug and vaccine delivery. They are most commonly formed by filling a microneedle mold with liquid formulation using vacuum or centrifugation to overcome the constraints of surface tension and solution viscosity. Here, we demonstrate a novel microneedle fabrication method employing an atomised spray technique that minimises the effects of the liquid surface tension and viscosity when filling molds. This spray method was successfully used to fabricate dissolvable microneedles (DMN) from a wide range of sugars (trehalose, fructose and raffinose) and polymeric materials (polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylmethylcellulose and sodium alginate). Fabrication by spraying produced microneedles with amorphous content using single sugar compositions. These microneedles displayed sharp tips and had complete fidelity to the master silicon template. Using a method to quantify the consistency of DMN penetration into different skin layers, we demonstrate that the material of construction significantly influenced the extent of skin penetration. We demonstrate that this spraying method can be adapted to produce novel laminate-layered as well as horizontally-layered DMN arrays. To our knowledge, this is the first report documenting the use of an atomising spray, at ambient, mild processing conditions, to create dissolvable microneedle arrays that can possess novel, laminate layering. Copyright © 2013 Elsevier B.V. All rights reserved.

Ceramic Honeycomb Structures and Method Thereof

NASA Technical Reports Server (NTRS)

Cagliostro, Domenick E.; Riccitiello, Salvatore R.

1989-01-01

The present invention relates to a method for producing ceramic articles and the articles, the process comprising the chemical vapor deposition (CVD) and/or chemical vapor infiltration (CVI) of a honeycomb structure. Specifically the present invention relates to a method for the production of a ceramic honeycomb structure, including: (a) obtaining a loosely woven fabric/binder wherein the fabric consists essentially of metallic, ceramic or organic fiber and the binder consists essentially of an organic or inorganic material wherein the fabric/binder has and retains a honeycomb shape, with the proviso that when the fabric is metallic or ceramic the binder is organic only; (b) substantially evenly depositing at least one layer of a ceramic on the fabric/binder of step (a); and (c) recovering the ceramic coated fiber honeycomb structure. In another aspect, the present invention relates to a method for the manufacture of a lightweight ceramic-ceramic composite honeycomb structure, which process comprises: (d) pyrolyzing a loosely woven fabric a honeycomb shaped and having a high char yield and geometric integrity after pyrolysis at between about 700 degrees and 1,100 degrees Centigrade; (e) substantially evenly depositing at least one layer of ceramic material on the pyrolyzed fabric of step (a); and (f) recovering the coated ceramic honeycomb structure. The ceramic articles produced have enhanced physical properties and are useful in aircraft and aerospace uses.

Probing dynamic behavior of electric fields and band diagrams in complex semiconductor heterostructures

NASA Astrophysics Data System (ADS)

Turkulets, Yury; Shalish, Ilan

2018-01-01

Modern bandgap engineered electronic devices are typically made of multi-semiconductor multi-layer heterostructures that pose a major challenge to silicon-era characterization methods. As a result, contemporary bandgap engineering relies mostly on simulated band structures that are hardly ever verified experimentally. Here, we present a method that experimentally evaluates bandgap, band offsets, and electric fields, in complex multi-semiconductor layered structures, and it does so simultaneously in all the layers. The method uses a modest optical photocurrent spectroscopy setup at ambient conditions. The results are analyzed using a simple model for electro-absorption. As an example, we apply the method to a typical GaN high electron mobility transistor structure. Measurements under various external electric fields allow us to experimentally construct band diagrams, not only at equilibrium but also under any other working conditions of the device. The electric fields are then used to obtain the charge carrier density and mobility in the quantum well as a function of the gate voltage over the entire range of operating conditions of the device. The principles exemplified here may serve as guidelines for the development of methods for simultaneous characterization of all the layers in complex, multi-semiconductor structures.

Using Combustion Synthesis to Reinforce Berms and Other Regolith Structures

NASA Technical Reports Server (NTRS)

Rodriquez, Gary

2013-01-01

The Moonraker Excavator and other tools under development for use on the Moon, Mars, and asteroids will be employed to construct a number of civil engineering projects and to mine the soil. Mounds of loose soil will be subject to the local transport mechanisms plus artificial mechanisms such as blast effects from landers and erosion from surface vehicles. Some of these structures will require some permanence, with a minimum of maintenance and upkeep. Combustion Synthesis (CS) is a family of processes and techniques whereby chemistry is used to transform materials, often creating flame in a hard vacuum. CS can be used to stabilize civil engineering works such as berms, habitat shielding, ramps, pads, roadways, and the like. The method is to unroll thin sheets of CS fabric between layers of regolith and then fire the fabric, creating a continuous sheet of crusty material to be interposed among layers of loose regolith. The combination of low-energy processes, ISRU (in situ resource utilization) excavator, and CS fabrics, seems compelling as a general method for establishing structures of some permanence and utility, especially in the role of robotic missions as precursors to manned exploration and settlement. In robotic precursory missions, excavator/ mobility ensembles mine the Lunar surface, erect constructions of soil, and dispense sheets of CS fabrics that are covered with layers of soil, fired, and then again covered with layers of soil, iterating until the desired dimensions and forms are achieved. At the base of each berm, for example, is a shallow trench lined with CS fabric, fired and filled, mounded, and then covered and fired, iteratively to provide a footing against lateral shear. A larger trench is host to a habitat module, backfilled, covered with fabric, covered with soil, and fired. Covering the applied CS fabric with layers of soil before firing allows the resulting matrix to incorporate soil both above and below the fabric ply into the fused layer, developing a very irregular surface which, like sandpaper, can provide an anchor for loose soil. CS fabrics employ a coarse fiberglass weave that persists as reinforcement for the fired material. The fiberglass softens at a temperature that exceeds the combustion temperature by factors of two to three, and withstands the installation process. This type of structure should be more resistant to rocket blast effects from Lunar landers.

Development and characterization of sub-monolayer coatings as novel calibration samples for X-ray spectroscopy

NASA Astrophysics Data System (ADS)

Hönicke, Philipp; Krämer, Markus; Lühl, Lars; Andrianov, Konstantin; Beckhoff, Burkhard; Dietsch, Rainer; Holz, Thomas; Kanngießer, Birgit; Weißbach, Danny; Wilhein, Thomas

2018-07-01

With the advent of both modern X-ray fluorescence (XRF) methods and improved analytical reliability requirements the demand for suitable reference samples has increased. Especially in nanotechnology with the very low areal mass depositions, quantification becomes considerably more difficult. However, the availability of suited reference samples is drastically lower than the demand. Physical vapor deposition techniques have been enhanced significantly in the last decade driven by the need for extremely precise film parameters in multilayer production. We have applied those techniques for the development of layer-like reference samples with mass depositions in the ng-range and well below for Ca, Cu, Pb, Mo, Pd, Pb, La, Fe and Ni. Numerous other elements would also be possible. Several types of reference samples were fabricated: multi-elemental layer and extremely low (sub-monolayer) samples for various applications in XRF and total-reflection XRF analysis. Those samples were characterized and compared at three different synchrotron radiation beamlines at the BESSY II electron storage ring employing the reference-free XRF approach based on physically calibrated instrumentation. In addition, the homogeneity of the multi-elemental coatings was checked at the P04 beamline at DESY. The measurements demonstrate the high precision achieved in the manufacturing process as well as the versatility of application fields for the presented reference samples.

Facile fabrication of uniaxial nanopatterns on shape memory polymer substrates using a complete bottom-up approach

NASA Astrophysics Data System (ADS)

Chen, Zhongbi; Krishnaswamy, Sridhar

2014-03-01

In earlier work, we have demonstrated an assisted self-assembly fabrication method for unidirectional submicron patterns using pre-programmed shape memory polymers (SMP) as the substrate in an organic/inorganic bilayer structure. In this paper, we propose a complete bottom-up method for fabrication of uniaxial wrinkles whose wavelength is below 300 nm. The method starts with using the aforementioned self-assembled bi-layer wrinkled surface as the template to make a replica of surface wrinkles on a PDMS layer which is spin-coated on a pre-programmed SMP substrate. When the shape recovery of the substrate is triggered by heating it to its transition temperature, the substrate has been programmed in such a way that it shrinks uniaxially to return to its permanent shape. Consequently, the wrinkle wavelength on PDMS reduces accordingly. A subsequent contact molding process is carried out on the PDMS layer spin-coated on another pre-programmed SMP substrate, but using the wrinkled PDMS surface obtained in the previous step as the master. By activating the shape recovery of the substrate, the wrinkle wavelength is further reduced a second time in a similar fashion. Our experiments showed that the starting wavelength of 640 nm decreased to 290 nm after two cycles of recursive molding. We discuss the advantages and limitations of our recursive molding approach compared to the prevalent top-down fabrication methods represented by lithography. The present study is expected to o er a simple and cost-e ective fabrication method of nano-scale uniaxial wrinkle patterns with the potential for large-scale mass-production.

Adhesive contact between a rigid spherical indenter and an elastic multi-layer coated substrate

PubMed Central

Stan, Gheorghe; Adams, George G.

2016-01-01

In this work the frictionless, adhesive contact between a rigid spherical indenter and an elastic multi-layer coated half-space was investigated by means of an integral transform formulation. The indented multi-layer coats were considered as made of isotropic layers that are perfectly bonded to each other and to an isotropic substrate. The adhesive interaction between indenter and contacting surface was treated as Maugis-type adhesion to provide general applicability within the entire range of adhesive interactions. By using a transfer matrix method, the stress-strain equations of the system were reduced to two coupled integral equations for the stress distribution under the indenter and the ratio between the adhesion radius and the contact radius, respectively. These resulting integral equations were solved through a numerical collocation technique, with solutions for the load dependencies of the contact radius and indentation depth for various values of the adhesion parameter and layer composition. The method developed here can be used to calculate the force-distance response of adhesive contacts on various inhomogeneous half-spaces that can be modeled as multi-layer coated half-spaces. PMID:27574338

A multi-layer steganographic method based on audio time domain segmented and network steganography

NASA Astrophysics Data System (ADS)

Xue, Pengfei; Liu, Hanlin; Hu, Jingsong; Hu, Ronggui

2018-05-01

Both audio steganography and network steganography are belong to modern steganography. Audio steganography has a large capacity. Network steganography is difficult to detect or track. In this paper, a multi-layer steganographic method based on the collaboration of them (MLS-ATDSS&NS) is proposed. MLS-ATDSS&NS is realized in two covert layers (audio steganography layer and network steganography layer) by two steps. A new audio time domain segmented steganography (ATDSS) method is proposed in step 1, and the collaboration method of ATDSS and NS is proposed in step 2. The experimental results showed that the advantage of MLS-ATDSS&NS over others is better trade-off between capacity, anti-detectability and robustness, that means higher steganographic capacity, better anti-detectability and stronger robustness.

Influence of the composite material thermal expansion on embedded highly birefringent polymer microstructured optical fibers

NASA Astrophysics Data System (ADS)

SzelÄ g, M.; Lesiak, P.; Kuczkowski, M.; Domański, A. W.; Woliński, T. R.

2013-05-01

Results of our research on embedded highly birefringent polymer microstructured fibers are presented. A composite material sample with fibers embedded between two layers of a multi-layer composite structure is fabricated and characterized. Temperature sensitivities of the polymer fibers are measured in a free space and compared with the fibers embedded in the composite material. It appeared that highly birefringent polymer microstructured fibers exhibit a strong increase in temperature sensitivity when embedded in the composite material, which is due to the stress-induced changes in birefringence created by thermally-induced strain.

Study on the Mechanical Properties of Bionic Coupling Layered B4C/5083Al Composite Materials

PubMed Central

Zhao, Qian; Liang, Yunhong; Liu, Qingping; Zhang, Zhihui; Yu, Zhenglei; Ren, Luquan

2018-01-01

Based on microstructure characteristics of Meretrix lusoria shell and Rapana venosa shell, bionic coupling layered B4C/5083Al composites with different layered structures and hard/soft combination models were fabricated via hot pressed sintering. The simplified bionic coupling models with hard and soft layers were similar to layered structure and hardness tendency of shells, guiding the bionic design and fabrication. B4C/5083Al composites with various B4C contents and pure 5083Al were treated as hard and soft layers, respectively. Hot pressed sintering maintained the designed bionic structure and enhanced high bonding strength between ceramics and matrix. Compared with B4C/5083Al composites, bionic layered composites exhibited high mechanical properties including flexural strength, fracture toughness, compressive strength and impact toughness. The hard layers absorbed applied loads in the form of intergranular fracture. Besides connection role, soft layers restrained slabbing phenomenon and reset extension direction of cracks among layers. The coupling functions of bionic composites proved the feasibility and practicability of bionic fabrication, providing a new method for improvement of ceramic/Al composite with properties of being lightweight and high mechanical strength. PMID:29701707

Fully inkjet-printed two-dimensional material field-effect heterojunctions for wearable and textile electronics.

PubMed

Carey, Tian; Cacovich, Stefania; Divitini, Giorgio; Ren, Jiesheng; Mansouri, Aida; Kim, Jong M; Wang, Chaoxia; Ducati, Caterina; Sordan, Roman; Torrisi, Felice

2017-10-31

Fully printed wearable electronics based on two-dimensional (2D) material heterojunction structures also known as heterostructures, such as field-effect transistors, require robust and reproducible printed multi-layer stacks consisting of active channel, dielectric and conductive contact layers. Solution processing of graphite and other layered materials provides low-cost inks enabling printed electronic devices, for example by inkjet printing. However, the limited quality of the 2D-material inks, the complexity of the layered arrangement, and the lack of a dielectric 2D-material ink able to operate at room temperature, under strain and after several washing cycles has impeded the fabrication of electronic devices on textile with fully printed 2D heterostructures. Here we demonstrate fully inkjet-printed 2D-material active heterostructures with graphene and hexagonal-boron nitride (h-BN) inks, and use them to fabricate all inkjet-printed flexible and washable field-effect transistors on textile, reaching a field-effect mobility of ~91 cm 2  V -1  s -1 , at low voltage (<5 V). This enables fully inkjet-printed electronic circuits, such as reprogrammable volatile memory cells, complementary inverters and OR logic gates.

Flexible fabrication of biomimetic compound eye array via two-step thermal reflow of simply pre-modeled hierarchic microstructures

NASA Astrophysics Data System (ADS)

Huang, Shengzhou; Li, Mujun; Shen, Lianguan; Qiu, Jinfeng; Zhou, Youquan

2017-06-01

A flexible fabrication method for the biomimetic compound eye (BCE) array is proposed. In this method, a triple-layer sandwich-like coating configuration was introduced, and the required hierarchic microstructures are formed with a simple single-scan exposure in maskless digital lithography. Taking advantage of the difference of glass transition point (Tg) between photoresists of each layer, the pre-formed hierarchic microstructures are in turn reflowed to the curved substrate and the BCE ommatidia in a two-step thermal reflow process. To avoid affecting the spherical substrate formed in the first thermal reflow, a non-contact strategy was proposed in the second reflow process. The measurement results were in good agreement with the designed BCE profiles. Results also showed that the fabricated BCE had good performances in optical test. The presented method is flexible, convenient, low-cost and can easily adapt to the fabrications of other optical elements with hierarchic microstructures.

Large-scale delamination of multi-layers transition metal carbides and carbonitrides “MXenes”

DOE PAGES

Naguib, Michael; Unocic, Raymond R.; Armstrong, Beth L.; ...

2015-04-17

Herein we report on a general approach to delaminate multi-layered MXenes using an organic base to induce swelling that in turn weakens the bonds between the MX layers. Simple agitation or mild sonication of the swollen MXene in water resulted in the large-scale delamination of the MXene layers. The delamination method is demonstrated for vanadium carbide, and titanium carbonitrides MXenes.

Method for fabrication of ceramic dielectric films on copper foils

DOEpatents

Ma, Beihai; Narayanan, Manoj; Dorris, Stephen E.; Balachandran, Uthamalingam

2015-03-10

The present invention provides a method for fabricating a ceramic film on a copper foil. The method comprises applying a layer of a sol-gel composition onto a copper foil. The sol-gel composition comprises a precursor of a ceramic material suspended in 2-methoxyethanol. The layer of sol-gel is then dried at a temperature up to about 250.degree. C. The dried layer is then pyrolyzed at a temperature in the range of about 300 to about 450.degree. C. to form a ceramic film from the ceramic precursor. The ceramic film is then crystallized at a temperature in the range of about 600 to about 750.degree. C. The drying, pyrolyzing and crystallizing are performed under a flowing stream of an inert gas. In some embodiments an additional layer of the sol-gel composition is applied onto the ceramic film and the drying, pyrolyzing and crystallizing steps are repeated for the additional layer to build up a thicker ceramic layer on the copper foil. The process can be repeated one or more times if desired.

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.

Metallic Nanowire Interconnections for Integrated Circuit Fabrication

NASA Technical Reports Server (NTRS)

Ng, Hou Tee (Inventor); Li, Jun (Inventor); Meyyappan, Meyya (Inventor)

2007-01-01

A method for fabricating an electrical interconnect between two or more electrical components. A conductive layer is provided on a substarte and a thin, patterned catalyst array is deposited on an exposed surface of the conductive layer. A gas or vapor of a metallic precursor of a metal nanowire (MeNW) is provided around the catalyst array, and MeNWs grow between the conductive layer and the catalyst array. The catalyst array and a portion of each of the MeNWs are removed to provide exposed ends of the MeNWs.

High performance SONOS flash memory with in-situ silicon nanocrystals embedded in silicon nitride charge trapping layer

NASA Astrophysics Data System (ADS)

Lim, Jae-Gab; Yang, Seung-Dong; Yun, Ho-Jin; Jung, Jun-Kyo; Park, Jung-Hyun; Lim, Chan; Cho, Gyu-seok; Park, Seong-gye; Huh, Chul; Lee, Hi-Deok; Lee, Ga-Won

2018-02-01

In this paper, SONOS-type flash memory device with highly improved charge-trapping efficiency is suggested by using silicon nanocrystals (Si-NCs) embedded in silicon nitride (SiNX) charge trapping layer. The Si-NCs were in-situ grown by PECVD without additional post annealing process. The fabricated device shows high program/erase speed and retention property which is suitable for multi-level cell (MLC) application. Excellent performance and reliability for MLC are demonstrated with large memory window of ∼8.5 V and superior retention characteristics of 7% charge loss for 10 years. High resolution transmission electron microscopy image confirms the Si-NC formation and the size is around 1-2 nm which can be verified again in X-ray photoelectron spectroscopy (XPS) where pure Si bonds increase. Besides, XPS analysis implies that more nitrogen atoms make stable bonds at the regular lattice point. Photoluminescence spectra results also illustrate that Si-NCs formation in SiNx is an effective method to form deep trap states.

Design, fabrication and characterization of LTCC-based electromagnetic microgenerators

NASA Astrophysics Data System (ADS)

Gierczak, M.; Markowski, P.; Dziedzic, A.

2016-02-01

Design, manufacturing process and properties of electromagnetic microgenerators fabricated in LTCC (Low Temperature Co-fired Ceramics) technology are presented in this paper. Electromagnetic microgenerators consist of planar coils spatially arranged on several layers of LTCC and of a multipole permanent magnet. Two different patterns of coils with 2-, 8-,10- and 12-layers and outer diameter of 50 mm were designed and fabricated. Silver-based pastes ESL 903-A or DuPont 6145 were used. In order to estimate the inductance of a single spatial coil the Greenhouse (self-inductance) and Hoer (mutual inductance) calculation methods were used. To verify the calculation results a single-layer coil was fabricated for each pattern and its inductance was measured using the precision RLC Meter. Fabricated LTCC microgenerators with embedded coils allow to generate voltage higher than ten volts and the electrical output power of approximately 600 mW at the rotor rotation speed of 12 thousands rpm. The self-made system was used for characterization of LTCC-based electromagnetic microgenerators.

Performance of a Diaphragmed Microlens for a Packaged Microspectrometer

PubMed Central

Lo, Joe; Chen, Shih-Jui; Fang, Qiyin; Papaioannou, Thanassis; Kim, Eun-Sok; Gundersen, Martin; Marcu, Laura

2009-01-01

This paper describes the design, fabrication, packaging and testing of a microlens integrated in a multi-layered MEMS microspectrometer. The microlens was fabricated using modified PDMS molding to form a suspended lens diaphragm. Gaussian beam propagation model was used to measure the focal length and quantify M2 value of the microlens. A tunable calibration source was set up to measure the response of the packaged device. Dual wavelength separation by the packaged device was demonstrated by CCD imaging and beam profiling of the spectroscopic output. We demonstrated specific techniques to measure critical parameters of microoptics systems for future optimization of spectroscopic devices. PMID:22399943

Conformal bi-layered perovskite/spinel coating on a metallic wire network for solid oxide fuel cells via an electrodeposition-based route

NASA Astrophysics Data System (ADS)

Park, Beom-Kyeong; Song, Rak-Hyun; Lee, Seung-Bok; Lim, Tak-Hyoung; Park, Seok-Joo; Jung, WooChul; Lee, Jong-Won

2017-04-01

Solid oxide fuel cells (SOFCs) require low-cost metallic components for current collection from electrodes as well as electrical connection between unit cells; however, the degradation of their electrical properties and surface stability associated with high-temperature oxidation is of great concern. It is thus important to develop protective conducting oxide coatings capable of mitigating the degradation of metallic components under SOFC operating conditions. Here, we report a conformal bi-layered coating composed of perovskite and spinel oxides on a metallic wire network fabricated by a facile electrodeposition-based route. A highly dense, crack-free, and adhesive bi-layered LaMnO3/Co3O4 coating of ∼1.2 μm thickness is conformally formed on the surfaces of wires with ∼100 μm diameter. We demonstrate that the bi-layered LaMnO3/Co3O4 coating plays a key role in improving the power density and durability of a tubular SOFC by stabilizing the surface of the metallic wire network used as a cathode current collector. The electrodeposition-based technique presented in this study offers a low-cost and scalable process to fabricate conformal multi-layered coatings on various metallic structures.

Development and coupling analysis of active skin antenna

NASA Astrophysics Data System (ADS)

Zhou, Jinzhu; Huang, Jin; He, Qingqang; Tang, Baofu; Song, Liwei

2017-02-01

An active skin antenna is a multifunctional composite structure that can provide load-bearing structure and steerable beam pointing functions, and is usually installed in the structural surface of aircraft, warships, and armored vehicles. This paper presents an innovative design of the active skin antenna, which consists of a package layer, control and signal processing layer, and RF (radio frequency) layer. The RF layer is fabricated by low temperature co-fired ceramics, with 64 microstrip antenna elements, tile transmitting and receiving modules, microchannel heat sinks, and feeding networks integrated into a functional block 2.8 mm thick. In this paper, a full-sized prototype of an active skin antenna was designed, fabricated, and tested. Moreover, a coupling analysis method was presented to evaluate the mechanical and electromagnetic performance of the active skin antenna subjected to aerodynamic loads. A deformed experimental system was built to validate the effectiveness of the coupling analysis method, which was also implemented to evaluate the performance of the active skin antenna when subjected to aerodynamic pressure. The fabricated specimen demonstrated structural configuration feasibility, and superior environmental load resistance.

Responsive and Adaptive Micro Wrinkles on Organic-inorganic Hybrid Materials.

PubMed

Takahashi, Masahide

2018-04-24

A buckling induced wrinkling is a general phenomenon in daily life, which is induced by mechanical instability at the interface of multi-layered systems. Variety of applications have been proposed for wrinkles in nano to micrometer periodicity on the surface of soft materials. In recent decades, researchers are trying to use wrinkles for variety of sophisticated applications such as micro pattern fabrication, control of wettability, templating/directing substrate for elongated nano materials or virus, size-selective adsorption/desorption of functional objects, cells or microorganisms, delamination induced material fabrication such as micro-rolls, substrates for stretchable electronics, valves for microfluidic devices and soft actuators. Herein, recent advances on the fabrication and application of micro-wrinkles are reviewed. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control of Evaporation Behavior of an Inkjet-Printed Dielectric Layer Using a Mixed-Solvent System

NASA Astrophysics Data System (ADS)

Yang, Hak Soon; Kang, Byung Ju; Oh, Je Hoon

2016-01-01

In this study, the evaporation behavior and the resulting morphology of inkjet-printed dielectric layers were controlled using a mixed-solvent system to fabricate uniform poly-4-vinylphenol (PVP) dielectric layers without any pinholes. The mixed-solvent system consisted of two different organic solvents: 1-hexanol and ethanol. The effects of inkjet-printing variables such as overlap condition, substrate temperature, and different printing sequences (continuous and interlacing printing methods) on the inkjet-printed dielectric layer were also investigated. Increasing volume fraction of ethanol (VFE) is likely to reduce the evaporation rate gradient and the drying time of the inkjet-printed dielectric layer; this diminishes the coffee stain effect and thereby improves the uniformity of the inkjet-printed dielectric layer. However, the coffee stain effect becomes more severe with an increase in the substrate temperature due to the enhanced outward convective flow. The overlap condition has little effect on the evaporation behavior of the printed dielectric layer. In addition, the interlacing printing method results in either a stronger coffee stain effect or wavy structures of the dielectric layers depending on the VFE of the PVP solution. All-inkjet-printed capacitors without electrical short circuiting can be successfully fabricated using the optimized PVP solution (VFE = 0.6); this indicates that the mixed-solvent system is expected to play an important role in the fabrication of high-quality inkjet-printed dielectric layers in various printed electronics applications.

Three-phase heterostructures f-NiFe2O4/PANI/PI EMI shielding fabric with high Microwave Absorption Performance

NASA Astrophysics Data System (ADS)

Wang, Yu; Wang, Wei; Yu, Dan

2017-12-01

In this work, a three-phase heterostructures f-NiFe2O4/PANI/PI EMI shielding fabric with a layer by layer structure was designed and prepared to obtain excellent microwave attenuation performance. Firstly, PANI/PI fabric was prepared via in-situ deposition method. Then, the NiFe2O4 nanoparticles functionalized by oleic acid were uniformly dispersed in epoxy resin and coated on the top and bottom of PANI/PI fabric with 0.041 mm total thickness. The investigation of chemical structure and surface morphologies indicated the composite structure of f-NiFe2O4/PANI/PI fabric. Various parameters like magnetic property, reflection loss and attenuation constant were used to evaluate its microwave attenuation performance. The results demonstrated that the 30f-NiFe2O4/PANI/PI fabric had a highest attenuation effectiveness with the minimum reflection loss value of -42.5 dB (>90% attenuation) at 12.5 GHz and the effective absorption bandwidth was 3.4 GHz. The study of attenuation mechanism indicated that the dielectric loss from PANI, the magnetic loss caused by f-NiFe2O4 and the layer by layer structure effectively improved microwave attenuation performance of composite fabric. Furthermore, the favorable flexibility and dimensional stability of this resultant fabric would allow the composite fabric for a long time service under pressure or foldable conditions. In sum, the study clearly indicated that three-phase heterostructures f-NiFe2O4/PANI/PI fabric was a good candidate as electromagnetic shielding materials in many fields.

Fabrication of ordered bulk heterojunction organic photovoltaic cells using nanopatterning and electrohydrodynamic spray deposition methods.

PubMed

Park, Sung-Eun; Kim, Sehwan; Kim, Kangmin; Joe, Hang-Eun; Jung, Buyoung; Kim, Eunkyoung; Kim, Woochul; Min, Byung-Kwon; Hwang, Jungho

2012-12-21

Organic photovoltaic cells with an ordered heterojunction (OHJ) active layer are expected to show increased performance. In the study described here, OHJ cells were fabricated using a combination of nanoimprinting and electrohydrodynamic (EHD) spray deposition methods. After an electron donor material was nanoimprinted with a PDMS stamp (valley width: 230 nm, period: 590 nm) duplicated from a Si nanomold, an electron acceptor material was deposited onto the nanoimprinted donor layer using an EHD spray deposition method. The donor-acceptor interface layer was observed by obtaining cross-sectional images with a focused ion beam (FIB) microscope. The photocurrent generation performance of the OHJ cells was evaluated with the current density-voltage curve under air mass (AM) 1.5 conditions. It was found that the surface morphology of the electron acceptor layer affected the current and voltage outputs of the photovoltaic cells. When an electron acceptor layer with a smooth thin (250 nm above the valley of the electron donor layer) surface morphology was obtained, power conversion efficiency was as high as 0.55%. The electrohydrodynamic spray deposition method used to produce OHJ photovoltaic cells provides a means for the adoption of large area, high throughput processes.

Stretchable electronics for wearable and high-current applications

NASA Astrophysics Data System (ADS)

Hilbich, Daniel; Shannon, Lesley; Gray, Bonnie L.

2016-04-01

Advances in the development of novel materials and fabrication processes are resulting in an increased number of flexible and stretchable electronics applications. This evolving technology enables new devices that are not readily fabricated using traditional silicon processes, and has the potential to transform many industries, including personalized healthcare, consumer electronics, and communication. Fabrication of stretchable devices is typically achieved through the use of stretchable polymer-based conductors, or more rigid conductors, such as metals, with patterned geometries that can accommodate stretching. Although the application space for stretchable electronics is extensive, the practicality of these devices can be severely limited by power consumption and cost. Moreover, strict process flows can impede innovation that would otherwise enable new applications. In an effort to overcome these impediments, we present two modified approaches and applications based on a newly developed process for stretchable and flexible electronics fabrication. This includes the development of a metallization pattern stamping process allowing for 1) stretchable interconnects to be directly integrated with stretchable/wearable fabrics, and 2) a process variation enabling aligned multi-layer devices with integrated ferromagnetic nanocomposite polymer components enabling a fully-flexible electromagnetic microactuator for large-magnitude magnetic field generation. The wearable interconnects are measured, showing high conductivity, and can accommodate over 20% strain before experiencing conductive failure. The electromagnetic actuators have been fabricated and initial measurements show well-aligned, highly conductive, isolated metal layers. These two applications demonstrate the versatility of the newly developed process and suggest potential for its furthered use in stretchable electronics and MEMS applications.

Simple Multi-level Microchannel Fabrication by Pseudo-Grayscale Backside Diffused Light Lithography.

PubMed

Lai, David; Labuz, Joseph M; Kim, Jiwon; Luker, Gary D; Shikanov, Ariella; Takayama, Shuichi

2013-11-14

Photolithography of multi-level channel features in microfluidics is laborious and/or costly. Grayscale photolithography is mostly used with positive photoresists and conventional front side exposure, but the grayscale masks needed are generally costly and positive photoresists are not commonly used in microfluidic rapid prototyping. Here we introduce a simple and inexpensive alternative that uses pseudo-grayscale (pGS) photomasks in combination with backside diffused light lithography (BDLL) and the commonly used negative photoresist, SU-8. BDLL can produce smooth multi-level channels of gradually changing heights without use of true grayscale masks because of the use of diffused light. Since the exposure is done through a glass slide, the photoresist is cross-linked from the substrate side up enabling well-defined and stable structures to be fabricated from even unspun photoresist layers. In addition to providing unique structures and capabilities, the method is compatible with the "garage microfluidics" concept of creating useful tools at low cost since pGS BDLL can be performed with the use of only hot plates and a UV transilluminator: equipment commonly found in biology labs. Expensive spin coaters or collimated UV aligners are not needed. To demonstrate the applicability of pGS BDLL, a variety of weir-type cell traps were constructed with a single UV exposure to separate cancer cells (MDA-MB-231, 10-15 μm in size) from red blood cells (RBCs, 2-8 μm in size) as well as follicle clusters (40-50 μm in size) from cancer cells (MDA-MB-231, 10-15 μm in size).

Multilayer moisture barrier

DOEpatents

Pankow, Joel W; Jorgensen, Gary J; Terwilliger, Kent M; Glick, Stephen H; Isomaki, Nora; Harkonen, Kari; Turkulainen, Tommy

2015-04-21

A moisture barrier, device or product having a moisture barrier or a method of fabricating a moisture barrier having at least a polymer layer, and interfacial layer, and a barrier layer. The polymer layer may be fabricated from any suitable polymer including, but not limited to, fluoropolymers such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), or ethylene-tetrafluoroethylene (ETFE). The interfacial layer may be formed by atomic layer deposition (ALD). In embodiments featuring an ALD interfacial layer, the deposited interfacial substance may be, but is not limited to, Al.sub.2O.sub.3, AlSiO.sub.x, TiO.sub.2, and an Al.sub.2O.sub.3/TiO.sub.2 laminate. The barrier layer associated with the interfacial layer may be deposited by plasma enhanced chemical vapor deposition (PECVD). The barrier layer may be a SiO.sub.xN.sub.y film.

Process for manufacturing multilayer capacitors

DOEpatents

Lauf, Robert J.; Holcombe, Cressie E.; Dykes, Norman L.

1996-01-01

The invention is directed to a method of manufacture of multilayer electrical components, especially capacitors, and components made by such a method. High capacitance dielectric materials and low cost metallizations layered with such dielectrics may be fabricated as multilayer electrical components by sintering the metallizations and the dielectrics during the fabrication process by application of microwave radiation.

Effects of printing-induced interfaces on localized strain within 3D printed hydrogel structures.

PubMed

Christensen, Kyle; Davis, Brian; Jin, Yifei; Huang, Yong

2018-08-01

Additive manufacturing, or 3D printing, is a promising approach for the fabrication of biological structures for regenerative medicine applications using tissue-like materials such as hydrogels. Herein, inkjet printing is implemented as a model droplet-based 3D printing technology for which interfaces have been shown to form between printed lines within printed layers of hydrogel structures. Experimental samples with interfaces in two orientations are fabricated by inkjet printing and control samples with and without interfaces are fabricated by extrusion printing and casting, respectively. The formation of partial and full interfaces is modeled in terms of printing conditions and gelation parameters, and an approach to predicting the ratio of interfacial area to the total contact area between two adjacent lines is presented. Digital image correlation is used to determine strain distributions and identify regions of increased localized deformation for samples under uniaxial tension. Despite the presence of interfaces in inkjet-printed samples, strain distributions are found to be homogeneous regardless of interface orientation, which may be attributed to the multi-layer nature of samples. Conversely, single-layer extrusion-printed samples exhibit localized regions of increased deformation between printed lines, indicating delamination along interfaces. The effective stiffness, failure strength, and failure strain of inkjet-printed samples are found to be dependent on the orientation of interfaces within layers. Specifically, inkjet-printed samples in which tensile forces pull apart interfaces exhibit significantly decreased mechanical properties compared to cast samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Histo-anatomic 3D printing of dental structures.

PubMed

Schweiger, J; Beuer, F; Stimmelmayr, M; Edelhoff, D; Magne, P; Güth, J F

2016-11-04

The creation of dental restorations with natural appearance and biomechanics represents a major challenge for the restorative team. The manufacturing-process of high-aesthetic restorations from tooth-coloured restorative materials is currently dominated by manual manufacturing procedures and the outcome is highly dependent on the knowledge and skills of the performing dental technician. On the other hand, due to the simplicity of the manufacturing process, CAD/CAM restorations from different material classes gain more and more acceptance in the daily routine. Multi-layered restorations show significant aesthetic advantages versus monolithic ones, but are difficult to fabricate using digital technologies. The key element for the successful automated digital fabrication of aesthetic anterior restorations seems to be the form of the individual dentine core as defined by dentine enamel junction (DEJ) covered by a more transparent layer of material imitating the enamel layer to create the outer enamel surface (OES). This article describes the possibilities and technologies available for so-called '4D-printing'. It introduces the digital manufacturing process of multilayered anterior teeth using 3D multipart printing, taking the example of manufacturing replicas of extracted intact natural teeth.

Development of mono-component and tri-component fibres 100% polymer based piezoelectric PVDF to harvest energy

NASA Astrophysics Data System (ADS)

Talbourdet, A.; Rault, F.; Cayla, A.; Cochrane, C.; Devaux, E.; Gonthier, A.; Lemort, G.; Campagne, C.

2017-10-01

A first study focused on the realization of a 100% Polyvinylidene fluoride woven fabric. The multi-filaments produced by melt spinning and studied by FTIR, X-Ray and DSC, were optimized in the β-phase, 97%, thanks drawing ratio of λ=5, and the processing temperature, 90°C. When the polar β-phase achieves a certain level in PVDF, the woven material is poling with fields up to about 6kV. DMA tests coupled to a Keithley voltmeter allow the solicitation of PVDF fabrics. A variation of voltage is obtained in compression, with a maximum output voltage of up to 2,3V. The other part of the study explains premises of a tricomponent fibre development, PEHD/PVDF/PA12. Two layers of conductive polymers acting as electrodes are placed on either side of the PVDF layer. The interfacial adhesion between the three different layers is analysed by SEM. The maximum stretch on melt spinning was fixed at 2.5 and the β-phase of the PVDF measured by X-Ray.

Distributed Multihoming Routing Method by Crossing Control MIPv6 with SCTP

NASA Astrophysics Data System (ADS)

Shi, Hongbo; Hamagami, Tomoki

There are various wireless communication technologies, such as 3G, WiFi, used widely in the world. Recently, not only the laptop but also the smart phones can be equipped with multiple wireless devices. The communication terminals which are implemented with multiple interfaces are usually called multi-homed nodes. Meanwhile, a multi-homed node with multiple interfaces can also be regarded as multiple single-homed nodes. For example, when a person who is using smart phone and laptop to connect to the Internet concurrently, we may regard the person as a multi-homed node in the Internet. This paper proposes a new routing method, Multi-homed Mobile Cross-layer Control to handle multi-homed mobile nodes. Our suggestion can provide a distributed end-to-end routing method for handling the communications among multi-homed nodes at the fundamental network layer.

Large core plastic planar optical splitter fabricated by 3D printing technology

NASA Astrophysics Data System (ADS)

Prajzler, Václav; Kulha, Pavel; Knietel, Marian; Enser, Herbert

2017-10-01

We report on the design, fabrication and optical properties of large core multimode optical polymer splitter fabricated using fill up core polymer in substrate that was made by 3D printing technology. The splitter was designed by the beam propagation method intended for assembling large core waveguide fibers with 735 μm diameter. Waveguide core layers were made of optically clear liquid adhesive, and Veroclear polymer was used as substrate and cover layers. Measurement of optical losses proved that the insertion optical loss was lower than 6.8 dB in the visible spectrum.

NIF optical materials and fabrication technologies: an overview

NASA Astrophysics Data System (ADS)

Campbell, John H.; Hawley-Fedder, Ruth A.; Stolz, Christopher J.; Menapace, Joseph A.; Borden, Michael R.; Whitman, Pamela K.; Yu, June; Runkel, Michael J.; Riley, Michael O.; Feit, Michael D.; Hackel, Richard P.

2004-05-01

The high-energy/high-power section of the NIF laser system contains 7360 meter-scale optics. Advanced optical materials and fabrication technologies needed to manufacture the NIF optics have been developed and put into production at key vendor sites. Production rates are up to 20 times faster and per-optic costs 5 times lower than could be achieved prior to the NIF. In addition, the optics manufactured for NIF are better than specification giving laser performance better than the design. A suite of custom metrology tools have been designed, built and installed at the vendor sites to verify compliance with NIF optical specifications. A brief description of the NIF optical wavefront specifications for the glass and crystal optics is presented. The wavefront specifications span a continuous range of spatial scale-lengths from 10 μm to 0.5 m (full aperture). We have continued our multi-year research effort to improve the lifetime (i.e. damage resistance) of bulk optical materials, finished optical surfaces and multi-layer dielectric coatings. New methods for post-processing the completed optic to improve the damage resistance have been developed and made operational. This includes laser conditioning of coatings, glass surfaces and bulk KDP and DKDP and well as raster and full aperture defect mapping systems. Research on damage mechanisms continues to drive the development of even better optical materials.

Environmentally-assisted technique for transferring devices onto non-conventional substrates

DOEpatents

Lee, Chi-Hwan; Kim, Dong Rip; Zheng, Xiaolin

2016-05-10

A device fabrication method includes: (1) providing a growth substrate including an oxide layer; (2) forming a metal layer over the oxide layer; (3) forming a stack of device layers over the metal layer; (4) performing fluid-assisted interfacial debonding of the metal layer to separate the stack of device layers and the metal layer from the growth substrate; and (5) affixing the stack of device layers to a target substrate.

Modulation of Morphology and Optical Property of Multi-Metallic PdAuAg and PdAg Alloy Nanostructures.

PubMed

Pandey, Puran; Kunwar, Sundar; Sui, Mao; Bastola, Sushil; Lee, Jihoon

2018-05-16

In this work, the evolution of PdAg and PdAuAg alloy nanostructures is demonstrated on sapphire (0001) via the solid-state dewetting of multi-metallic thin films. Various surface configurations, size, and arrangements of bi- and tri-metallic alloy nanostructures are fabricated as a function of annealing temperature, annealing duration, film thickness, and deposition arrangements such as bi-layers (Pd/Ag), tri-layers (Pd/Au/Ag), and multi-layers (Pd/Au/Ag × 5). Specifically, the tri-layers film shows the gradual evolution of over-grown NPs, voids, wiggly nanostructures, and isolated PdAuAg alloy nanoparticles (NPs) along with the increased annealing temperature. In contrast, the multi-layers film with same thickness show the enhanced dewetting rate, which results in the formation of voids at relatively lower temperature, wider spacing, and structural regularity of alloy NPs at higher temperature. The dewetting enhancement is attributed to the increased number of interfaces and reduced individual layer thickness, which aid the inter-diffusion process at the initial stage. In addition, the time evolution of the Pd 150 nm /Ag 80 nm bi-layer films at constant temperature show the wiggly-connected and isolated PdAg alloy NPs. The overall evolution of alloy NPs is discussed based on the solid-state dewetting mechanism in conjunction with the diffusion, inter-diffusion, alloying, sublimation, Rayleigh instability, and surface energy minimization. Depending upon their surface morphologies, the bi- and tri-metallic alloy nanostructures exhibit the dynamic reflectance spectra, which show the formation of dipolar (above 700 nm) and quadrupolar resonance peaks (~ 380 nm) and wide dips in the visible region as correlated to the localized surface plasmon resonance (LSPR) effect. An absorption dip is readily shifted from ~ 510 to ~ 475 nm along with the decreased average size of alloy nanostructures.

Modulation of Morphology and Optical Property of Multi-Metallic PdAuAg and PdAg Alloy Nanostructures

NASA Astrophysics Data System (ADS)

Pandey, Puran; Kunwar, Sundar; Sui, Mao; Bastola, Sushil; Lee, Jihoon

2018-05-01

In this work, the evolution of PdAg and PdAuAg alloy nanostructures is demonstrated on sapphire (0001) via the solid-state dewetting of multi-metallic thin films. Various surface configurations, size, and arrangements of bi- and tri-metallic alloy nanostructures are fabricated as a function of annealing temperature, annealing duration, film thickness, and deposition arrangements such as bi-layers (Pd/Ag), tri-layers (Pd/Au/Ag), and multi-layers (Pd/Au/Ag × 5). Specifically, the tri-layers film shows the gradual evolution of over-grown NPs, voids, wiggly nanostructures, and isolated PdAuAg alloy nanoparticles (NPs) along with the increased annealing temperature. In contrast, the multi-layers film with same thickness show the enhanced dewetting rate, which results in the formation of voids at relatively lower temperature, wider spacing, and structural regularity of alloy NPs at higher temperature. The dewetting enhancement is attributed to the increased number of interfaces and reduced individual layer thickness, which aid the inter-diffusion process at the initial stage. In addition, the time evolution of the Pd150 nm/Ag80 nm bi-layer films at constant temperature show the wiggly-connected and isolated PdAg alloy NPs. The overall evolution of alloy NPs is discussed based on the solid-state dewetting mechanism in conjunction with the diffusion, inter-diffusion, alloying, sublimation, Rayleigh instability, and surface energy minimization. Depending upon their surface morphologies, the bi- and tri-metallic alloy nanostructures exhibit the dynamic reflectance spectra, which show the formation of dipolar (above 700 nm) and quadrupolar resonance peaks ( 380 nm) and wide dips in the visible region as correlated to the localized surface plasmon resonance (LSPR) effect. An absorption dip is readily shifted from 510 to 475 nm along with the decreased average size of alloy nanostructures.

Amorphous Inorganic Electron-Selective Layers for Efficient Perovskite Solar Cells: Feasible Strategy Towards Room-Temperature Fabrication.

PubMed

Wang, Kai; Shi, Yantao; Li, Bo; Zhao, Liang; Wang, Wei; Wang, Xiangyuan; Bai, Xiaogong; Wang, Shufeng; Hao, Ce; Ma, Tingli

2016-03-02

Inorganic electron-selective layers (ESLs) are fabricated at extremely low temperatures of 70°C or even 25°C by a simple solution route. This is of great significance because the attained PCEs confirm the feasibility of room-temperature coating of inorganic amorphous ESLs through a solution method for the first time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tetradymite layer assisted heteroepitaxial growth and applications

DOEpatents

Stoica, Vladimir A.; Endicott, Lynn; Clarke, Roy; Uher, Ctirad

2017-08-01

A multilayer stack including a substrate, an active layer, and a tetradymite buffer layer positioned between the substrate and the active layer is disclosed. A method for fabricating a multilayer stack including a substrate, a tetradymite buffer layer and an active layer is also disclosed. Use of such stacks may be in photovoltaics, solar cells, light emitting diodes, and night vision arrays, among other applications.

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

Method for forming silicon on a glass substrate

DOEpatents

McCarthy, Anthony M.

1995-01-01

A method by which single-crystal silicon microelectronics may be fabricated on glass substrates at unconventionally low temperatures. This is achieved by fabricating a thin film of silicon on glass and subsequently forming the doped components by a short wavelength (excimer) laser doping procedure and conventional patterning techniques. This method may include introducing a heavily boron doped etch stop layer on a silicon wafer using an excimer laser, which permits good control of the etch stop layer removal process. This method additionally includes dramatically reducing the remaining surface roughness of the silicon thin films after etching in the fabrication of silicon on insulator wafers by scanning an excimer laser across the surface of the silicon thin film causing surface melting, whereby the surface tension of the melt causes smoothing of the surface during recrystallization. Applications for this method include those requiring a transparent or insulating substrate, such as display manufacturing. Other applications include sensors, actuators, optoelectronics, radiation hard and high temperature electronics.

Method for forming silicon on a glass substrate

DOEpatents

McCarthy, A.M.

1995-03-07

A method by which single-crystal silicon microelectronics may be fabricated on glass substrates at unconventionally low temperatures. This is achieved by fabricating a thin film of silicon on glass and subsequently forming the doped components by a short wavelength (excimer) laser doping procedure and conventional patterning techniques. This method may include introducing a heavily boron doped etch stop layer on a silicon wafer using an excimer laser, which permits good control of the etch stop layer removal process. This method additionally includes dramatically reducing the remaining surface roughness of the silicon thin films after etching in the fabrication of silicon on insulator wafers by scanning an excimer laser across the surface of the silicon thin film causing surface melting, whereby the surface tension of the melt causes smoothing of the surface during recrystallization. Applications for this method include those requiring a transparent or insulating substrate, such as display manufacturing. Other applications include sensors, actuators, optoelectronics, radiation hard and high temperature electronics. 15 figs.

Multi-junction solar cell device

DOEpatents

Friedman, Daniel J.; Geisz, John F.

2007-12-18

A multi-junction solar cell device (10) is provided. The multi-junction solar cell device (10) comprises either two or three active solar cells connected in series in a monolithic structure. The multi-junction device (10) comprises a bottom active cell (20) having a single-crystal silicon substrate base and an emitter layer (23). The multi-junction device (10) further comprises one or two subsequent active cells each having a base layer (32) and an emitter layer (23) with interconnecting tunnel junctions between each active cell. At least one layer that forms each of the top and middle active cells is composed of a single-crystal III-V semiconductor alloy that is substantially lattice-matched to the silicon substrate (22). The polarity of the active p-n junction cells is either p-on-n or n-on-p. The present invention further includes a method for substantially lattice matching single-crystal III-V semiconductor layers with the silicon substrate (22) by including boron and/or nitrogen in the chemical structure of these layers.

Single step sequential polydimethylsiloxane wet etching to fabricate a microfluidic channel with various cross-sectional geometries

NASA Astrophysics Data System (ADS)

Wang, C.-K.; Liao, W.-H.; Wu, H.-M.; Lo, Y.-H.; Lin, T.-R.; Tung, Y.-C.

2017-11-01

Polydimethylsiloxane (PDMS) has become a widely used material to construct microfluidic devices for various biomedical and chemical applications due to its desirable material properties and manufacturability. PDMS microfluidic devices are usually fabricated using soft lithography replica molding methods with master molds made of photolithogrpahy patterned photoresist layers on silicon wafers. The fabricated microfluidic channels often have rectangular cross-sectional geometries with single or multiple heights. In this paper, we develop a single step sequential PDMS wet etching process that can be used to fabricate microfluidic channels with various cross-sectional geometries from single-layer PDMS microfluidic channels. The cross-sections of the fabricated channel can be non-rectangular, and varied along the flow direction. Furthermore, the fabricated cross-sectional geometries can be numerically simulated beforehand. In the experiments, we fabricate microfluidic channels with various cross-sectional geometries using the developed technique. In addition, we fabricate a microfluidic mixer with alternative mirrored cross-sectional geometries along the flow direction to demonstrate the practical usage of the developed technique.

Method for fabricating multi-strand superconducting cable

DOEpatents

Borden, A.R.

1985-04-01

Multi-strand superconducting cables adapted to be used, for example, to wind a magnet are fabricated by directing wire strands inwardly from spools disposed on the perimeter of a rotating disk and wrapping them diagonally around a tapered mandrel with a flattened cross-sectional shape with a core having a wedge-shaped channel. As the cable is pulled axially, flexibly coupled wedge-shaped pieces are continuously passed through the channel in the mandrel and inserted into the cable as an internal support therefor.

Apparatus and method for fabricating multi-strand superconducting cable

DOEpatents

Borden, Albert R.

1986-01-01

Multi-strand superconducting cables adapted to be used, for example, to wind a magnet is fabricated by directing wire strands inwardly from spools disposed on the perimeter of a rotating disk and wrapping them diagonally around a tapered mandrel with a flattened cross-sectional shape with a core having a wedge-shaped channel. As the cable is pulled axially, flexibly coupled wedge-shaped pieces are continuously passed through the channel in the mandrel and inserted into the cable as an internal support therefor.

Evaluation of the dielectric function of colloidal Cd1 - xHgxTe quantum dot films by spectroscopic ellipsometry

NASA Astrophysics Data System (ADS)

Bejaoui, A.; Alonso, M. I.; Garriga, M.; Campoy-Quiles, M.; Goñi, A. R.; Hetsch, F.; Kershaw, S. V.; Rogach, A. L.; To, C. H.; Foo, Y.; Zapien, J. A.

2017-11-01

We report on the investigation by spectroscopic ellipsometry of films containing Cd1 - xHgxTe alloy quantum dots (QDs). The alloy QDs were fabricated from colloidal CdTe QDs grown by an aqueous synthesis process followed by an ion-exchange step in which Hg2+ ions progressively replace Cd2+. For ellipsometric studies, several films were prepared on glass substrates using layer-by-layer (LBL) deposition. The contribution of the QDs to the measured ellipsometric spectra is extracted from a multi-sample, transmission and multi- angle-of-incidence ellipsometric data analysis fitted using standard multilayer and effective medium models that include surface roughness effects, modeled by an effective medium approximation. The relationship of the dielectric function of the QDs retrieved from these studies to that of the corresponding II-VI bulk material counterparts is presented and discussed.

Multi-channel feature dictionaries for RGB-D object recognition

NASA Astrophysics Data System (ADS)

Lan, Xiaodong; Li, Qiming; Chong, Mina; Song, Jian; Li, Jun

2018-04-01

Hierarchical matching pursuit (HMP) is a popular feature learning method for RGB-D object recognition. However, the feature representation with only one dictionary for RGB channels in HMP does not capture sufficient visual information. In this paper, we propose multi-channel feature dictionaries based feature learning method for RGB-D object recognition. The process of feature extraction in the proposed method consists of two layers. The K-SVD algorithm is used to learn dictionaries in sparse coding of these two layers. In the first-layer, we obtain features by performing max pooling on sparse codes of pixels in a cell. And the obtained features of cells in a patch are concatenated to generate patch jointly features. Then, patch jointly features in the first-layer are used to learn the dictionary and sparse codes in the second-layer. Finally, spatial pyramid pooling can be applied to the patch jointly features of any layer to generate the final object features in our method. Experimental results show that our method with first or second-layer features can obtain a comparable or better performance than some published state-of-the-art methods.

A microfluidic multi-injector for gradient generation.

PubMed

Chung, Bong Geun; Lin, Francis; Jeon, Noo Li

2006-06-01

This paper describes a microfluidic multi-injector (MMI) that can generate temporal and spatial concentration gradients of soluble molecules. Compared to conventional glass micropipette-based methods that generate a single gradient, the MMI exploits microfluidic integration and actuation of multiple pulsatile injectors to generate arbitrary overlapping gradients that have not previously been possible. The MMI device is fabricated in poly(dimethylsiloxane) (PDMS) using multi-layer soft lithography and consists of fluidic channels and control channels with pneumatically actuated on-chip barrier valves. Repetitive actuation of on-chip valves control pulsatile release of solution that establishes microscopic chemical gradients around the orifice. The volume of solution released per actuation cycle ranged from 30 picolitres to several hundred picolitres and increased linearly with the duration of valve opening. The shape of the measured gradient profile agreed closely with the simulated diffusion profile from a point source. Steady state gradient profiles could be attained within 10 minutes, or less with an optimized pulse sequence. Overlapping gradients from 2 injectors were generated and characterized to highlight the advantages of MMI over conventional micropipette assays. The MMI platform should be useful for a wide range of basic and applied studies on chemotaxis and axon guidance.

Method for fabricating a microscale anemometer

NASA Technical Reports Server (NTRS)

Liu, Chang (Inventor); Chen, Jack (Inventor)

2008-01-01

Method for fabricating a microscale anemometer on a substrate. A sacrificial layer is formed on the substrate, and a metal thin film is patterned to form a sensing element. At least one support for the sensing element is patterned. The sacrificial layer is removed, and the sensing element is lifted away from the substrate by raising the supports, thus creating a clearance between the sensing element and the substrate to allow fluid flow between the sensing element and the substrate. The supports are raised preferably by use of a magnetic field applied to magnetic material patterned on the supports.

Study of thickness and uniformity of oxide passivation with DI-O3 on silicon substrate for electronic and photonic applications

NASA Astrophysics Data System (ADS)

Sharma, Mamta; Hazra, Purnima; Singh, Satyendra Kumar

2018-05-01

Since the beginning of semiconductor fabrication technology evolution, clean and passivated substrate surface is one of the prime requirements for fabrication of Electronic and optoelectronic device fabrication. However, as the scale of silicon circuits and device architectures are continuously decreased from micrometer to nanometer (from VLSI to ULSI technology), the cleaning methods to achieve better wafer surface qualities has raised research interests. The development of controlled and uniform silicon dioxide is the most effective and reliable way to achieve better wafer surface quality for fabrication of electronic devices. On the other hand, in order to meet the requirement of high environment safety/regulatory standards, the innovation of cleaning technology is also in demand. The controlled silicon dioxide layer formed by oxidant de-ionized ozonated water has better uniformity. As the uniformity of the controlled silicon dioxide layer is improved on the substrate, it enhances the performance of the devices. We can increase the thickness of oxide layer, by increasing the ozone time treatment. We reported first time to measurement of thickness of controlled silicon dioxide layer and obtained the uniform layer for same ozone time.

Biosensors Fabricated through Electrostatic Assembly of Enzymes/Polyelectrolyte Hybrid Layers on Carbon Nanotubes

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

Lin, Yuehe; Liu, Guodong; Wang, Jun

2006-06-01

Carbon nanotubes (CNTs) have emerged as new class of nanomaterials that is receiving considerable interest because of their unique structure, mechanical, and electronic properties. One promising application of CNTs is to fabricate highly sensitive chemo/biosensors.1-4 For construction of these CNT-based sensors, the CNTs first have to be modified with some molecules specific to the interests. Generally, covalent binding, affinity, and electrostatic interaction have been utilized for the modification of CNTs. Among them, the electrostatic method is attractive due to its simplicity and high efficiency. In present work, we have developed highly sensitively amperometric biosensors for glucose, choline, organophosphate pesticide (OPP)more » and nerve agents (NAs) based on electrostatically assembling enzymes on the surface of CNTs. All these biosensors were fabricated by immobilization of enzymes on the negatively charged CNTs surface through alternately assembling a cationic poly(diallydimethylammonium chloride) (PDDA) layer and an enzyme layer. Using this layer-by-layer (LBL) technique, a bioactive nanocomposite film was fabricated on the electrode surface. Owing to the electrocatalytic effect of CNTs, an amplified electrochemical signal was achieved, which leads to low detections limits for glucose, choline, and OPP and NAs.« less

Site-specific characterization of beetle horn shell with micromechanical bending test in focused ion beam system.

PubMed

Lee, Hyun-Taek; Kim, Ho-Jin; Kim, Chung-Soo; Gomi, Kenji; Taya, Minoru; Nomura, Shûhei; Ahn, Sung-Hoon

2017-07-15

Biological materials are the result of years of evolution and possess a number of efficient features and structures. Researchers have investigated the possibility of designing biomedical structures that take advantage of these structural features. Insect shells, such as beetle shells, are among the most promising types of biological material for biomimetic development. However, due to their intricate geometries and small sizes, it is challenging to measure the mechanical properties of these microscale structures. In this study, we developed an in-situ testing platform for site-specific experiments in a focused ion beam (FIB) system. Multi-axis nano-manipulators and a micro-force sensor were utilized in the testing platform to allow better results in the sample preparation and data acquisition. The entire test protocol, consisting of locating sample, ion beam milling and micro-mechanical bending tests, can be carried out without sample transfer or reattachment. We used our newly devised test platform to evaluate the micromechanical properties and structural features of each separated layer of the beetle horn shell. The Young's modulus of both the exocuticle and endocuticle layers was measured. We carried out a bending test to characterize the layers mechanically. The exocuticle layer bent in a brick-like manner, while the endocuticle layer exhibited a crack blunting effect. This paper proposed an in-situ manipulation/test method in focused ion beam for characterizing micromechanical properties of beetle horn shell. The challenge in precise and accurate fabrication for the samples with complex geometry was overcome by using nano-manipulators having multi-degree of freedom and a micro-gripper. With the aid of this specially designed test platform, bending tests were carried out on cantilever-shaped samples prepared by focused ion beam milling. Structural differences between exocuticle and endocuticle layers of beetle horn shell were explored and the results provided insight into the structural advantages of each biocomposite structure. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Blunt Trauma Performance of Fabric Systems Utilizing Natural Rubber Coated High Strength Fabrics

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

Ahmad, M. R.; Ahmad, W. Y. W.; Samsuri, A.

2010-03-11

The blunt trauma performance of fabric systems against 9 mm bullets is reported. Three shots were fired at each fabric system with impact velocity of 367+-9 m/s and the depth of indentation on the modeling clay backing was measured. The results showed that 18-layer and 21-layer all-neat fabric systems failed the blunt trauma test. However, fabric systems with natural rubber (NR) latex coated fabric layers gave lower blunt trauma of between 25-32 mm indentation depths. Deformations on the neat fabrics upon impact were identified as broken yarns, yarn stretching and yarn pull-out. Deflections of the neat fabrics were more localised.more » For the NR latex coated fabric layers, no significant deformation can be observed except for peeled-off regions of the NR latex film at the back surface of the last layer. From the study, it can be said that the NR latex coated fabric layers were effective in reducing the blunt trauma of fabric systems.« less

Mode switching in a multi-wavelength distributed feedback quantum cascade laser using an external micro-cavity

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

Sidler, Meinrad; Institute for Quantum Electronics, ETH Zurich, Wolfgang-Pauli-Strasse 16, 8093 Zurich; Rauter, Patrick

2014-02-03

We demonstrate a multi-wavelength distributed feedback (DFB) quantum cascade laser (QCL) operating in a lensless external micro-cavity and achieve switchable single-mode emission at three distinct wavelengths selected by the DFB grating, each with a side-mode suppression ratio larger than 30 dB. Discrete wavelength tuning is achieved by modulating the feedback experienced by each mode of the multi-wavelength DFB QCL, resulting from a variation of the external cavity length. This method also provides a post-fabrication control of the lasing modes to correct for fabrication inhomogeneities, in particular, related to the cleaved facets position.

Verification and validation of an advanced model of heat and mass transfer in the protective clothing

NASA Astrophysics Data System (ADS)

Łapka, Piotr; Furmański, Piotr

2018-04-01

The paper presents verification and validation of an advanced numerical model of heat and moisture transfer in the multi-layer protective clothing and in components of the experimental stand subjected to either high surroundings temperature or high radiative heat flux emitted by hot objects. The developed model included conductive-radiative heat transfer in the hygroscopic porous fabrics and air gaps as well as conductive heat transfer in components of the stand. Additionally, water vapour diffusion in the pores and air spaces as well as phase transition of the bound water in the fabric fibres (sorption and desorption) were accounted for. All optical phenomena at internal or external walls were modelled and the thermal radiation was treated in the rigorous way, i.e., semi-transparent absorbing, emitting and scattering fabrics with the non-grey properties were assumed. The air was treated as transparent. Complex energy and mass balances as well as optical conditions at internal or external interfaces were formulated in order to find values of temperatures, vapour densities and radiation intensities at these interfaces. The obtained highly non-linear coupled system of discrete equations was solved by the Finite Volume based in-house iterative algorithm. The developed model passed discretisation convergence tests and was successfully verified against the results obtained applying commercial software for simplified cases. Then validation was carried out using experimental measurements collected during exposure of the protective clothing to high radiative heat flux emitted by the IR lamp. Satisfactory agreement of simulated and measured temporal variation of temperature at external and internal surfaces of the multi-layer clothing was attained.

Mesoporous multi-shelled ZnO microspheres for the scattering layer of dye sensitized solar cell with a high efficiency

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

Xia, Weiwei; Mei, Chao; Zeng, Xianghua, E-mail: xhzeng@yzu.edu.cn

2016-03-14

Both light scattering and dye adsorbing are important for the power conversion efficiency PCE performance of dye sensitized solar cell (DSSC). Nanostructured scattering layers with a large specific surface area are regarded as an efficient way to improve the PCE by increasing dye adsorbing, but excess adsorbed dye will hinder light scattering and light penetration. Thus, how to balance the dye adsorbing and light penetration is a key problem to improve the PCE performance. Here, multiple-shelled ZnO microspheres with a mesoporous surface are fabricated by a hydrothermal method and are used as scattering layers on the TiO{sub 2} photoanode ofmore » the DSSC in the presence of N719 dye and iodine–based electrolyte, and the results reveal that the DSSCs based on triple shelled ZnO microsphere with a mesoporous surface exhibit an enhanced PCE of 7.66%, which is 13.0% higher than those without the scattering layers (6.78%), indicating that multiple-shelled microspheres with a mesoporous surface can ensure enough light scattering between the shells, and a favorable concentration of the adsorbed dye can improve the light penetration. These results may provide a promising pathway to obtain the high efficient DSSCs.« less

Method of depositing multi-layer carbon-based coatings for field emission

DOEpatents

Sullivan, John P.; Friedmann, Thomas A.

1999-01-01

A novel field emitter device for cold cathode field emission applications, comprising a multi-layer resistive carbon film. The multi-layered film of the present invention is comprised of at least two layers of a resistive carbon material, preferably amorphous-tetrahedrally coordinated carbon, such that the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure comprises a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film comprises a plurality of carbon layers, wherein adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced. Field emitters made according the present invention display improved electron emission characteristics in comparison to conventional field emitter materials.

Method of depositing multi-layer carbon-based coatings for field emission

DOEpatents

Sullivan, J.P.; Friedmann, T.A.

1999-08-10

A novel field emitter device is disclosed for cold cathode field emission applications, comprising a multi-layer resistive carbon film. The multi-layered film of the present invention is comprised of at least two layers of a resistive carbon material, preferably amorphous-tetrahedrally coordinated carbon, such that the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure comprises a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film comprises a plurality of carbon layers, wherein adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced. Field emitters made according the present invention display improved electron emission characteristics in comparison to conventional field emitter materials. 8 figs.

Process for manufacturing multilayer capacitors

DOEpatents

Lauf, R.J.; Holcombe, C.E.; Dykes, N.L.

1996-01-02

The invention is directed to a method of manufacture of multilayer electrical components, especially capacitors, and components made by such a method. High capacitance dielectric materials and low cost metallizations layered with such dielectrics may be fabricated as multilayer electrical components by sintering the metallizations and the dielectrics during the fabrication process by application of microwave radiation. 4 figs.

Hybrid method of making an amorphous silicon P-I-N semiconductor device

DOEpatents

Moustakas, Theodore D.; Morel, Don L.; Abeles, Benjamin

1983-10-04

The invention is directed to a hydrogenated amorphous silicon PIN semiconductor device of hybrid glow discharge/reactive sputtering fabrication. The hybrid fabrication method is of advantage in providing an ability to control the optical band gap of the P and N layers, resulting in increased photogeneration of charge carriers and device output.

Three-dimensionally patterned energy absorptive material and method of fabrication

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

Duoss, Eric; Frank, James M.; Kuntz, Joshua

A three-dimensionally patterned energy absorptive material and fabrication method having multiple layers of patterned filaments extrusion-formed from a curable pre-cursor material and stacked and cured in a three-dimensionally patterned architecture so that the energy absorptive material produced thereby has an engineered bulk property associated with the three-dimensionally patterned architecture.

One-step direct-laser metal writing of sub-100 nm 3D silver nanostructures in a gelatin matrix

NASA Astrophysics Data System (ADS)

Kang, SeungYeon; Vora, Kevin; Mazur, Eric

2015-03-01

Developing an ability to fabricate high-resolution, 3D metal nanostructures in a stretchable 3D matrix is a critical step to realizing novel optoelectronic devices such as tunable bulk metal-dielectric optical devices and THz metamaterial devices that are not feasible with alternative techniques. We report a new chemistry method to fabricate high-resolution, 3D silver nanostructures using a femtosecond-laser direct metal writing technique. Previously, only fabrication of 3D polymeric structures or single-/few-layer metal structures was possible. Our method takes advantage of unique gelatin properties to overcome such previous limitations as limited freedom in 3D material design and short sample lifetime. We fabricate more than 15 layers of 3D silver nanostructures with a resolution of less than 100 nm in a stable dielectric matrix that is flexible and has high large transparency that is well-matched for potential applications in the optical and THz metamaterial regimes. This is a single-step process that does not require any further processing. This work will be of interest to those interested in fabrication methods that utilize nonlinear light-matter interactions and the realization of future metamaterials.

Anti-rewet felt for use in a papermaking machine

DOEpatents

Beck, David A.

2003-09-09

An anti-rewet fabric is used for carrying a fiber web through an air press. The anti-rewet fabric includes at least one air distribution fabric layer, one air distribution fabric layer being configured for contacting the fiber web, and a perforated film layer, the perforated film layer being made of a polyester film. The perforated film layer has a first film side and a second film side, the first film side being one of laminated and attached to the one air distribution fabric layer.

Nanoporous Al sandwich foils using size effect of Al layer thickness during Cu/Al/Cu laminate rolling

NASA Astrophysics Data System (ADS)

Yu, Hailiang; Lu, Cheng; Tieu, A. Kiet; Li, Huijun; Godbole, Ajit; Kong, Charlie

2018-06-01

The roll bonding technique is one of the most widely used methods to produce metal laminate sheets. Such sheets offer interesting research opportunities for both scientists and engineers. In this paper, we report on an experimental investigation of the 'thickness effect' during laminate rolling for the first time. Using a four-high multifunction rolling mill, Cu/Al/Cu laminate sheets were fabricated with a range of thicknesses (16, 40, 70 and 130 μm) of the Al layer. The thickness of the Cu sheets was a constant 300 μm. After rolling, TEM images show good bonding quality between the Cu and Al layers. However, there are many nanoscale pores in the Al layer. The fraction of nanoscale pores in the Al layer increases with a reduction in the Al layer thickness. The finite element method was used to simulate the Cu/Al/Cu rolling process. The simulation results reveal the effect of the Al layer thickness on the deformation characteristics of the Cu/Al/Cu laminate. Finally, we propose that the size effect of the Al layer thickness during Cu/Al/Cu laminate rolling may offer a method to fabricate 'nanoporous' Al sandwich laminate foils. Such foils can be used in electromagnetic shielding of electrical devices and noisy shielding of building.

Environmentally-assisted technique for transferring devices onto non-conventional substrates

DOEpatents

Lee, Chi-Hwan; Kim, Dong Rip; Zheng, Xiaolin

2014-08-26

A device fabrication method includes: (1) providing a growth substrate including a base and an oxide layer disposed over the base; (2) forming a metal layer over the oxide layer; (3) forming a stack of device layers over the metal layer; (4) performing interfacial debonding of the metal layer to separate the stack of device layers and the metal layer from the growth substrate; and (5) affixing the stack of device layers to a target substrate.

A regenerating ultrasensitive electrochemical impedance immunosensor for the detection of adenovirus.

PubMed

Lin, Donghai; Tang, Thompson; Jed Harrison, D; Lee, William E; Jemere, Abebaw B

2015-06-15

We report on the development of a regenerable sensitive immunosensor based on electrochemical impedance spectroscopy for the detection of type 5 adenovirus. The multi-layered immunosensor fabrication involved successive modification steps on gold electrodes: (i) modification with self-assembled layer of 1,6-hexanedithiol to which gold nanoparticles were attached via the distal thiol groups, (ii) formation of self-assembled monolayer of 11-mercaptoundecanoic acid onto the gold nanoparticles, (iii) covalent immobilization of monoclonal anti-adenovirus 5 antibody, with EDC/NHS coupling reaction on the nanoparticles, completing the immunosensor. The immunosensor displayed a very good detection limit of 30 virus particles/ml and a wide linear dynamic range of 10(5). An electrochemical reductive desorption technique was employed to completely desorb the components of the immunosensor surface, then re-assemble the sensing layer and reuse the sensor. On a single electrode, the multi-layered immunosensor could be assembled and disassembled at least 30 times with 87% of the original signal intact. The changes of electrode behavior after each assembly and desorption processes were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

Freestanding and Reactive Thin Films Fabricated by Covalent Layer-by-Layer Assembly and Subsequent Lift-Off of Azlactone-Containing Polymer Multilayers

PubMed Central

Buck, Maren E.

2010-01-01

We report an approach to the fabrication of freestanding and amine-reactive thin films that is based on the reactive layer-by-layer assembly and subsequent lift-off of azlactone-containing polymer multilayers. We demonstrate that covalently crosslinked multilayers fabricated using the azlactone-functionalized polymer poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) and a primary amine-containing polymer [poly(ethyleneimine) (PEI)] can be delaminated from planar glass and silicon surfaces by immersion in mildly acidic aqueous environments to yield flexible freestanding membranes. These freestanding membranes are robust and can withstand exposure to strong acid, strong base, or incubation in high ionic strength solutions that typically lead to the disruption and erosion of polymer multilayers assembled by reversible weak interactions (e.g., ‘polyelectrolyte multilayers’ assembled by electrostatic interactions or hydrogen bonding). We demonstrate further that these PEI/PVDMA assemblies contain residual reactive azlactone functionality that can be exploited to chemically modify the films (either directly after fabrication or after they have been lifted off of the substrates on which they were fabricated) using a variety of amine-functionalized small molecules. These freestanding membranes can also be transferred readily onto other objects (for example, onto the surfaces of planar substrates containing holes or pores) to fabricate suspended polymer membranes and other film-functionalized interfaces. In addition to planar, two-dimensional freestanding films, this approach can be used to fabricate and isolate three-dimensional freestanding membranes (e.g., curved films or tubes) by layer-by-layer assembly on, and subsequent lift-off from, the surfaces of topologically complex substrates (e.g., the curved ends of glass tubing, etc.). The results of this investigation, when combined, suggest the basis of methods for the fabrication of stable, chemically-reactive, and flexible polymer thin films and membranes of potential utility in a variety of fundamental and applied contexts. PMID:20857952

Fabrication and Characterization of Functionally Graded Cathodes for Solid Oxide Fuel Cells

NASA Astrophysics Data System (ADS)

Simonet, J.; Kapelski, G.; Bouvard, D.

2008-02-01

Solid oxide fuel cells are multi-layered designed. The most prevalent structure is an anode supported cell with a thick porous layer of nickel oxide NiO and yttrium stabilized zirconia (YSZ) composite acting as an anode, a thin dense layer of YSZ as an electrolyte, a composite thin porous layer of lanthanum strontium manganate LSM and YSZ and a current collector layer of porous LSM. Regular operating temperature is 1000 °C. The industrial development requires designing cathodes with acceptable electrochemical and mechanical properties at a lower temperature, typically between 700 and 800 °C. A solution consists in designing composite bulk cathodes with more numerous electro-chemical reaction sites. This requirement could be met by grading the composition of the cathode in increasing the YSZ volume fraction near the electrolyte and the LSM volume fraction near the current collector layer so that the repartition of reaction sites and the interfacial adhesion between the cathode and electrolyte layers are optimal. The fabrication of graded composite cathode has been investigated using a sedimentation process that consists of preparing a suspension containing the powder mixture and allowing the particles to fall by gravity upon a substrate. Different composite cathodes with continuous composition gradient have been obtained by sedimentation of LSM and YSZ powder mixture upon a dense YSZ substrate and subsequent firing. Their compositions and microstructures have been analysed with Scanning Electron Microscope (SEM) and Electron Dispersive Spectrometry (EDS).

Method of fabricating boron containing coatings

DOEpatents

Makowiecki, Daniel M.; Jankowski, Alan F.

1999-01-01

Hard coatings are fabricated from boron nitride, cubic boron nitride, and multilayer boron/cubic boron nitride, and the fabrication thereof involves magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron is formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/cubic boron nitride, is produced by depositing alternate layers of boron and cubic boron nitride, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be discrete or of a blended or graded composition.

Method of fabricating boron containing coatings

DOEpatents

Makowiecki, D.M.; Jankowski, A.F.

1999-04-27

Hard coatings are fabricated from boron nitride, cubic boron nitride, and multilayer boron/cubic boron nitride, and the fabrication thereof involves magnetron sputtering in a selected atmosphere. These hard coatings may be applied to tools and engine and other parts, as well to reduce wear on tribological surfaces and electronic devices. These boron coatings contain no morphological growth features. For example, the boron is formed in an inert (e.g. argon) atmosphere, while the cubic boron nitride is formed in a reactive (e.g. nitrogen) atmosphere. The multilayer boron/cubic boron nitride, is produced by depositing alternate layers of boron and cubic boron nitride, with the alternate layers having a thickness of 1 nanometer to 1 micrometer, and at least the interfaces of the layers may be discrete or of a blended or graded composition. 3 figs.

Vacuum-deposited polymer/silver reflector material

NASA Astrophysics Data System (ADS)

Affinito, John D.; Martin, Peter M.; Gross, Mark E.; Bennett, Wendy D.

1994-09-01

Weatherable, low cost, front surface, solar reflectors on flexible substrates would be highly desirable for lamination to solar concentrator panels. The method to be described in this paper may permit such reflector material to be fabricated for less the 50$CNT per square foot. Vacuum deposited Polymer/Silver/Polymer reflectors and Fabry-Perot interference filters were fabricated in a vacuum web coating operation on polyester substrates. Reflectivities were measured in the wavelength range from .4 micrometers to .8 micrometers . It is hoped that a low cost substrate can be used with the substrate laminated to the concentrator and the weatherable acrylic polymer coating facing the sun. This technique should be capable of deposition line speeds approaching 1500 linear feet/minute2. Central to this technique is a new vacuum deposition process for the high rate deposition of polymer films. This polymer process involves the flash evaporation of an acrylic monomer onto a moving substrate. The monomer is subsequently cured by an electron beam or ultraviolet light. This high speed polymer film deposition process has been named the PML process- for Polymer Multi- Layer.

Hydrangea-like magneto-fluorescent nanoparticles through thiol-inducing assembly

NASA Astrophysics Data System (ADS)

Chen, Shun; Zhang, Junjun; Song, Shaokun; Xiong, Chuanxi; Dong, Lijie

2017-01-01

Magneto-fluorescent nanoparticles (NPs), recognized as an emerging class of materials, have drawn much attention because of their potential applications. Due to surface functionalization and thiol-metal bonds, a simple method has been put forward for fabricating hydrangea-like magneto-fluorescent Fe3O4-SH@QD NPs, through assembling thiol-modified Fe3O4 NPs with sub-size multi-layer core/shell CdSe/CdS/ZnS QDs. After a refined but controllable silane hydrolysis process, thiol-modified Fe3O4 was fabricated, resulting in Fe3O4-SH@QD NPs with QDs, while preventing the quenching of the QDs. As a result, the core Fe3O4 NPs were 18 nm in diameter, while the scattered CdSe/CdS/ZnS QDs were 7 nm in diameter. The resultant magneto-fluorescent Fe3O4-SH@QD NPs exhibit efficient fluorescence, superparamagnetism at room temperature, and rapid response to the external field, which make them ideal candidates for difunctional probes in MRI and bio-labels, targeting and photodynamic therapy, and cell tracking and separation.