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Sample records for low-resistive precision fabric

  1. Micro Machining Enhances Precision Fabrication

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Advanced thermal systems developed for the Space Station Freedom project are now in use on the International Space Station. These thermal systems employ evaporative ammonia as their coolant, and though they employ the same series of chemical reactions as terrestrial refrigerators, the space-bound coolers are significantly smaller. Two Small Business Innovation Research (SBIR) contracts between Creare Inc. of Hanover, NH and Johnson Space Center developed an ammonia evaporator for thermal management systems aboard Freedom. The principal investigator for Creare Inc., formed Mikros Technologies Inc. to commercialize the work. Mikros Technologies then developed an advanced form of micro-electrical discharge machining (micro-EDM) to make tiny holes in the ammonia evaporator. Mikros Technologies has had great success applying this method to the fabrication of micro-nozzle array systems for industrial ink jet printing systems. The company is currently the world leader in fabrication of stainless steel micro-nozzles for this market, and in 2001 the company was awarded two SBIR research contracts from Goddard Space Flight Center to advance micro-fabrication and high-performance thermal management technologies.

  2. Precise Fabrication of Electromagnetic-Levitation Coils

    NASA Technical Reports Server (NTRS)

    Ethridge, E.; Curreri, P.; Theiss, J.; Abbaschian, G.

    1985-01-01

    Winding copper tubing on jig ensures reproducible performance. Sequence of steps insures consistent fabrication of levitation-and-melting coils. New method enables technician to produce eight coils per day, 95 percent of them acceptable. Method employs precise step-by-step procedure on specially designed wrapping and winding jig.

  3. Precision Metal Fabrication. Florida Vocational Program Guide.

    ERIC Educational Resources Information Center

    University of South Florida, Tampa. Dept. of Adult and Vocational Education.

    This guide identifies considerations in the organization, operation, and evaluation of secondary and postsecondary vocational education programs. It contains both a vocational program guide and Career Merit Achievement Plan (Career MAP) for precision metal fabrication. The guide contains the following sections: occupational description; program…

  4. Low resistance barrier layer for isolating, adhering, and passivating copper metal in semiconductor fabrication

    DOEpatents

    Weihs, Timothy P.; Barbee, Jr., Troy W.

    2002-01-01

    Cubic or metastable cubic refractory metal carbides act as barrier layers to isolate, adhere, and passivate copper in semiconductor fabrication. One or more barrier layers of the metal carbide are deposited in conjunction with copper metallizations to form a multilayer characterized by a cubic crystal structure with a strong (100) texture. Suitable barrier layer materials include refractory transition metal carbides such as vanadium carbide (VC), niobium carbide (NbC), tantalum carbide (TaC), chromium carbide (Cr.sub.3 C.sub.2), tungsten carbide (WC), and molybdenum carbide (MoC).

  5. Batch fabrication of precision miniature permanent magnets

    DOEpatents

    Christenson, Todd R.; Garino, Terry J.; Venturini, Eugene L.

    2002-01-01

    A new class of processes for fabrication of precision miniature rare earth permanent magnets is disclosed. Such magnets typically have sizes in the range 0.1 to 10 millimeters, and dimensional tolerances as small as one micron. Very large magnetic fields can be produced by such magnets, lending to their potential application in MEMS and related electromechanical applications, and in miniature millimeter-wave vacuum tubes. This abstract contains simplifications, and is supplied only for purposes of searching, not to limit or alter the scope or meaning of any claims herein.

  6. Precise carbon control of fabricated stainless steel

    DOEpatents

    Nilsen, R.J.

    1975-12-01

    A process is described for controlling the carbon content of fabricated stainless steel components including the steps of heat treating the component in hydrogen atmospheres of varying dewpoints and carbon potentials.

  7. Fabrication and metrology of high-precision freeform surfaces

    NASA Astrophysics Data System (ADS)

    Supranowitz, Chris; Dumas, Paul; Nitzsche, Tobias; DeGroote Nelson, Jessica; Light, Brandon B.; Medicus, Kate; Smith, Nathan

    2013-09-01

    Freeform applications are growing and include helmet-mounted displays, conformal optics (e.g. windows integrated into airplane wings), and those requiring the extreme precision of EUV. These non-rotationally symmetric surfaces pose challenges to optical fabrication, mostly in the areas of polishing and metrology. The varying curvature of freeform surfaces drives the need for smaller, more "conformal", tools for polishing and reference beams for interferometry. In this paper, we present fabrication results of a high-precision freeform surface. We will discuss the total manufacturing process, including generation, pre-polishing, MRF®, and metrology, highlighting the capabilities available in today's optical fabrication companies.

  8. A unique approach to fabricating precision space structures elements

    NASA Technical Reports Server (NTRS)

    Cohan, H.; Johnson, R. R.

    1981-01-01

    A procedure of fabricating graphite epoxy columns used in the assembly of large space platforms is described. The requirement for precise dimensional control led to a unique hot resin injection process. Dry, high modulus fiber is wound over a vertically mounted steam-heated mandrel. A steam-heated sleeve or caul is slipped over the wound mandrel and resin is injected and cured in place. Approximately 200 column elements have been fabricated using this efficient process.

  9. Atomically Precise Bottom-up Fabrication of Graphene Nanoribbons

    NASA Astrophysics Data System (ADS)

    Cai, Jinming

    2011-03-01

    Graphene nanoribbons (GNRs) -- narrow stripes of graphene -- are predicted to exhibit remarkable properties making them suitable for future electronic applications. Contrary to their two-dimensional (2D) parent material graphene, which exhibits semimetallic behavior, GNRs with widths smaller than 10 nm are predicted to be semiconductors due to quantum confinement and edge effects. Despite significant advances in GNR fabrication using chemical, sonochemical and lithographic methods as well as recent reports on the successful unzipping of carbon nanotubes into GNRs, the production of sub-10 nm GNRs with chemical precision remains a major challenge. In this talk, we will present a simple GNR fabrication method that allows for the production of atomically precise GNRs of different topologies and widths. Our bottom-up approach consists in the surface-assisted coupling of suitably designed molecular precursors into linear polyphenylenes and their subsequent cyclodehydrogenation, and results in GNRs whose topology, width and edge periphery are defined by the precursor monomers. By means of STM and Raman characterization, we demonstrate that this fabrication process allows for the atomically precise fabrication of complex GNR topologies. Furthermore, we have developed a reliable procedure to transfer GNRs fabricated on metal surfaces onto other substrates. It will for example be shown that millimeter sized sheets of crosslinked GNRs can be transferred onto silicon wafers, making them available for further processing, e.g. by lithography, prototype device fabrication and characterization. Coauthors: Pascal Ruffieux, Rached Jaafar, Marco Bieri, Thomas Braun, and Stephan Blankenburg, Empa, Swiss Federal Laboratories for Materials Science and Technology, 3602 Thun and 8600 Dübendorf, Switzerland; Matthias Muoth, ETH Zurich, Department of Mechanical and Process Engineering, 8092 Zurich, Switzerland; Ari P. Seitsonen, University of Zurich, Physical Chemistry Institute, 8057

  10. Atomically precise bottom-up fabrication of graphene nanoribbons.

    PubMed

    Cai, Jinming; Ruffieux, Pascal; Jaafar, Rached; Bieri, Marco; Braun, Thomas; Blankenburg, Stephan; Muoth, Matthias; Seitsonen, Ari P; Saleh, Moussa; Feng, Xinliang; Müllen, Klaus; Fasel, Roman

    2010-07-22

    Graphene nanoribbons-narrow and straight-edged stripes of graphene, or single-layer graphite-are predicted to exhibit electronic properties that make them attractive for the fabrication of nanoscale electronic devices. In particular, although the two-dimensional parent material graphene exhibits semimetallic behaviour, quantum confinement and edge effects should render all graphene nanoribbons with widths smaller than 10 nm semiconducting. But exploring the potential of graphene nanoribbons is hampered by their limited availability: although they have been made using chemical, sonochemical and lithographic methods as well as through the unzipping of carbon nanotubes, the reliable production of graphene nanoribbons smaller than 10 nm with chemical precision remains a significant challenge. Here we report a simple method for the production of atomically precise graphene nanoribbons of different topologies and widths, which uses surface-assisted coupling of molecular precursors into linear polyphenylenes and their subsequent cyclodehydrogenation. The topology, width and edge periphery of the graphene nanoribbon products are defined by the structure of the precursor monomers, which can be designed to give access to a wide range of different graphene nanoribbons. We expect that our bottom-up approach to the atomically precise fabrication of graphene nanoribbons will finally enable detailed experimental investigations of the properties of this exciting class of materials. It should even provide a route to graphene nanoribbon structures with engineered chemical and electronic properties, including the theoretically predicted intraribbon quantum dots, superlattice structures and magnetic devices based on specific graphene nanoribbon edge states.

  11. Fabrication of Au nanoparticle/double-walled carbon nanotube film/TiO2 nanotube array/Ti heterojunctions with low resistance state for broadband photodetectors

    NASA Astrophysics Data System (ADS)

    Chen, Yan; Zhang, Guowei; Dong, Zhanmin; Wei, Jinquan; Zhu, Jia-Lin; Sun, Jia-Lin

    2017-03-01

    A broadband photodetector based on Au nanoparticle/double-walled carbon nanotube film/TiO2 nanotube array /Ti multilayer heterojunction structures has been fabricated. A pre-electroforming process at a voltage bias of 35 V was used to switch the photodetector from a high resistance state to a low resistance state. At a voltage bias of 1 V under 532-nm laser illumination in air, the photoresponsivity of the device reached 15.41 mA W-1, which is enhanced by approximately 1.91 times when compared with that of device before deposition of Au nanoparticles. In addition, in a vacuum under a voltage bias of 1 V, the photoresponsivity of the device reached 23.29 mA W-1 and 6.85 mA W-1 at 532 nm and 1064 nm, respectively. The surface plasmon polaritons of the Au nanoparticles allowed extension of the sensitivity of the photosensitive regions into the mid-infrared range. The experimental results show that the device photoresponsivity reached 2.26 mA W-1 at a voltage bias of 1 V under 10.6-μm laser illumination in air.

  12. High-precision structure fabrication based on an etching resistance layer

    NASA Astrophysics Data System (ADS)

    Zhang, Man; Deng, Qiling; Shi, Lifang; Cao, Axiu; Pang, Hui; Liu, Xin; Wang, Jiazhou; Hu, Song

    2016-10-01

    The high-precision fabrication of micro-/nano-structure is a challenge. In this paper, we proposed a new fabrication method of high-precision structure based on an etching resistance layer. The high-precision features were fabricated by photolithography technique, followed by the etching process to transfer the features to the substrate. During this process, the etching uniformity and error lead to the feature distortion. We introduced an etching resistance layer between feature layer and substrate. The etching process will stop when arriving at the resistance layer. Due to the high precision of the plating film, the high-precision structure depth was achieved. In our experiment, we introduced aluminum trioxide as the etching resistance layer. The structures with low depth error of less than 5% were fabricated.

  13. Fabrication of precision optics using an imbedded reference surface

    DOEpatents

    Folta, James A.; Spiller, Eberhard

    2005-02-01

    The figure of a substrate is very precisely measured and a figured-correcting layer is provided on the substrate. The thickness of the figure-correcting layer is locally measured and compared to the first measurement. The local measurement of the figure-correcting layer is accomplished through a variety of methods, including interferometry and fluorescence or ultrasound measurements. Adjustments in the thickness of the figure-correcting layer are made until the top of the figure-correcting layer matches a desired figure specification.

  14. Precise Fabrication of Silicon Wafers Using Gas Cluster Ion Beams

    SciTech Connect

    Isogai, Hiromichi; Toyoda, Eiji; Izunome, Koji; Kashima, Kazuhiko; Mashita, Takafumi; Toyoda, Noriaki; Yamada, Isao

    2009-03-10

    Precise surface processing of a silicon wafer was studied by using a gas cluster ion beam (GCIB). The damage caused to the silicon surface was strongly dependent on irradiation parameters. The extent of damage varied with the species of source gas and the acceleration voltage (Va) of cluster ions. It also varied with the cluster size and residual gas pressure. The influence of electron acceleration voltage (Ve) used for ionization of a neutral cluster was also investigated. The irradiation damage, such as an amorphous silicon (a-Si) layer, a mixed layer of a-Si and c-Si (transition layer), and surface roughness, was increased with Ve. It is suggested that the increase in the amount of energy per atom was induced by high Ve, because of variation of the cluster size and/or cluster charge. An undamaged smooth surface can be produced by Ar-GCIB irradiation at low Ve and Va.

  15. Precision glass molding: Toward an optimal fabrication of optical lenses

    NASA Astrophysics Data System (ADS)

    Zhang, Liangchi; Liu, Weidong

    2017-03-01

    It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 105 to 1012 Pas due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

  16. Precision glass molding: Toward an optimal fabrication of optical lenses

    NASA Astrophysics Data System (ADS)

    Zhang, Liangchi; Liu, Weidong

    2016-12-01

    It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 105 to 1012 Pas due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

  17. Cliché fabrication method using precise roll printing process with 5 um pattern width

    NASA Astrophysics Data System (ADS)

    Shin, Yejin; Kim, Inyoung; Oh, Dong-Ho; Lee, Taik-Min

    2016-09-01

    Among the printing processes for printed electronic devices, gravure offset and reverse offset method have drawn attention for its fine pattern printing possibility. These printing methods use cliché, which has critical effect on the final product precision and quality. In this research, a novel precise cliché replica method is proposed. It consists of copper sputtering, precise mask pattern printing with 5 um width using reverse offset printing, Ni electroplating, lift-off, etching, and DLC coating. We finally compare the fabricated replica cliché with the original one and print out precise patterns using the replica cliché.

  18. SNAP: fabrication of long coupled microresonator chains with sub-angstrom precision.

    PubMed

    Sumetsky, M; Dulashko, Y

    2012-12-03

    Based on the recently-introduced Surface Nanoscale Axial Photonics (SNAP) platform, we demonstrate a chain of 30 coupled SNAP microresonators spaced by 50 micron along an optical fiber, which is fabricated with the precision of 0.7 angstrom and a standard deviation of 0.12 angstrom in effective microresonator radius. To the best of our knowledge, this result surpasses those achieved in other super-low-loss photonic technologies developed to date by two orders of magnitude. The chain exhibits bandgaps in both the discrete and continuous spectrum in excellent agreement with theory. The developed method enables robust fabrication of SNAP devices with sub-angstrom precision.

  19. Electron Transport Layer-Free Inverted Organic Solar Cells Fabricated with Highly Transparent Low-Resistance Indium Gallium Zinc Oxide/Ag/Indium Gallium Zinc Oxide Multilayer Electrode

    NASA Astrophysics Data System (ADS)

    Kim, Jun Ho; Kwon, Sung-Nam; Na, Seok-In; Kim, Sun-Kyung; Yoo, Young-Zo; Im, Hyeong-Seop; Seong, Tae-Yeon

    2017-04-01

    Inverted organic solar cells (OSCs) have been fabricated with conventional Sn-doped indium oxide (ITO) and amorphous indium gallium zinc oxide (a-IGZO)/Ag/a-IGZO (39 nm/19 nm/39 nm) (a-IAI) electrodes and their electrical characteristics characterized. The ITO and optimized a-IAI electrodes showed high transmittance of 96% and 88% at 500 nm, respectively. The carrier concentration and sheet resistance of the ITO and a-IAI films were 8.46 × 1020 cm-3 and 7.96 × 1021 cm-3 and 14.18 Ω/sq and 4.24 Ω/sq, respectively. Electron transport layer (ETL)-free OSCs with the a-IAI electrode exhibited power conversion efficiency (PCE) of 2.66%, similar to that of ZnO ETL-based OSCs with ITO electrode (3.27%). However, the ETL-free OSCs with the a-IAI electrode showed much higher PCE than the ETL-free OSCs with the ITO electrode (0.84%). Ultraviolet photoelectron spectroscopy results showed that the work function of the a-IAI electrode was 4.15 eV. This improved performance was attributed to the various roles of the a-IAI electrode, e.g., as an effective ETL and a hole blocking layer.

  20. Improved transfer process for fabrication of cantilever with precise air-gap formation

    NASA Astrophysics Data System (ADS)

    Kanazawa, Shusuke; Kusaka, Yasuyuki; Yamamoto, Noritaka; Ushijima, Hirobumi

    2017-05-01

    In this paper, an improved transfer process to fabricate a cantilever structure with a precise air gap is reported. For this fabrication, a planar imprinting method was used and the drying conditions of the cantilever precursor ink were controlled. The air gap between the cantilevered top and bottom electrodes was formed with an estimated error of less than 3%. An operational force gauge with a changeable capacitance was obtained by applying a force to the cantilevered top electrode. This process can facilitate the eco-friendly fabrication of micro-devices with three-dimensional structures.

  1. Design, fabrication, characterization of a polymeric nano-precision micro z-stage

    NASA Astrophysics Data System (ADS)

    Ghaderi, M.; Beygi Azar Aghbolagh, F.; Taghavi, M.; Sabri, I.; Sadegh, M.; Latifi, H.

    2012-06-01

    Many applications in micro and nanotechnologies require micron-sized components, capable of positioning in ranges of sub-micrometers to a few microns. This paper reports on the design, fabrication and characterization procedure of an electrostatically actuated polymeric Nano-precision micro z-stage. Due to its ease of fabrication and great variety of functionalities, polymers have become an important material in micro fabrication technology. In contrast to piezoelectric stages, polymeric micro stage has a comparatively simple and cost effective fabrication procedure. Furthermore, low Young's Modulus of polymers made them a suitable basic material in comparison with their traditional counterparts. In this paper, SU-8 photoresist was used as the construction material and the photolithography technique were used to realize the stage. SU-8 with its low Young's modulus (5 GPa), has a higher tendency for bending, compared to, for example, silicon nitride (150-350 GPa). These properties make the SU-8 polymer, suitable for various applications.

  2. Fabrication of the Advanced X-ray Astrophysics Facility (AXAF) Optics: A Deterministic, Precision Engineering Approach to Optical Fabrication

    NASA Technical Reports Server (NTRS)

    Gordon, T. E.

    1995-01-01

    The mirror assembly of the AXAF observatory consists of four concentric, confocal, Wolter type 1 telescopes. Each telescope includes two conical grazing incidence mirrors, a paraboloid followed by a hyperboloid. Fabrication of these state-or-the-art optics is now complete, with predicted performance that surpasses the goals of the program. The fabrication of these optics, whose size and requirements exceed those of any previous x-ray mirrors, presented a challenging task requiring the use of precision engineering in many different forms. Virtually all of the equipment used for this effort required precision engineering. Accurate metrology required deterministic support of the mirrors in order to model the gravity distortions which will not be present on orbit. The primary axial instrument, known as the Precision Metrology Station (PMS), was a unique scanning Fizeau interferometer. After metrology was complete, the optics were placed in specially designed Glass Support Fixtures (GSF's) for installation on the Automated Cylindrical Grinder/Polishers (ACG/P's). The GSF's were custom molded for each mirror element to match the shape of the outer surface to minimize distortions of the inner surface. The final performance of the telescope is expected to far exceed the original goals and expectations of the program.

  3. A new fabrication method for precision antenna reflectors for space flight and ground test

    NASA Technical Reports Server (NTRS)

    Sharp, G. Richard; Wanhainen, Joyce S.; Ketelsen, Dean A.

    1991-01-01

    Communications satellites are using increasingly higher frequencies that require increasingly precise antenna reflectors for use in space. Traditional industry fabrication methods for space antenna reflectors employ successive modeling techniques using high- and low-temperature molds for reflector face sheets and then a final fit-up of the completed honeycomb sandwich panel antenna reflector to a master pattern. However, as new missions are planned at much higher frequencies, greater accuracies will be necessary than are achievable using these present methods. A new approach for the fabrication of ground-test solid-surface antenna reflectors is to build a rigid support structure with an easy-to-machine surface. This surface is subsequently machined to the desired reflector contour and coated with a radio-frequency-reflective surface. This method was used to fabricate a 2.7-m-diameter ground-test antenna reflector to an accuracy of better than 0.013 mm (0.0005 in.) rms. A similar reflector for use on spacecraft would be constructed in a similar manner but with space-qualified materials. The design, analysis, and fabrication of the 2.7-m-diameter precision antenna reflector for antenna ground tests and the extension of this technology to precision, space-based antenna reflectors are described.

  4. First-principles study on bottom-up fabrication process of atomically precise graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Kaneko, Tomoaki; Tajima, Nobuo; Ohno, Takahisa

    2016-06-01

    We investigate the energetics of a polyanthracene formation in the bottom-up fabrication of atomically precise graphene nanoribbons on Au(111) using first-principles calculations based on the density functional theory. We show that the structure of precursor molecules plays a decisive role in the C-C coupling reaction. The reaction energy of the dimerization of anthracene dimers is a larger negative value than that of the dimerization of anthracene monomers, suggesting that the precursor molecule used in experiments has a favorable structure for graphene nanoribbon fabrication.

  5. Fabrication and Assembly of High-Precision Hinge and Latch Joints for Deployable Optical Instruments

    NASA Technical Reports Server (NTRS)

    Phelps, James E.

    1999-01-01

    Descriptions are presented of high-precision hinge and latch joints that have been co-developed, for application to deployable optical instruments, by NASA Langley Research Center and Nyma/ADF. Page-sized versions of engineering drawings are included in two appendices to describe all mechanical components of both joints. Procedures for assembling the mechanical components of both joints are also presented. The information herein is intended to facilitate the fabrication and assembly of the high-precision hinge and latch joints, and enable the incorporation of these joints into the design of deployable optical instrument systems.

  6. Production and characterization of polymer microspheres containing trace explosives using precision particle fabrication technology.

    PubMed

    Staymates, Matthew; Fletcher, Robert; Staymates, Jessica; Gillen, Greg; Berkland, Cory

    2010-01-01

    Well characterized test materials are essential for validating the performance of current trace explosive detection systems. These test materials must replicate trace explosive contamination in the form of small particles with characteristic diameters in the micrometer range. In this work, Precision Particle Fabrication was used to fabricate monodisperse polymer microspheres that contain high explosives. Three high explosives were successfully incorporated into the microspheres. Ion mobility spectrometry confirmed that the encapsulation efficiency was typically greater than 50%, with some suspected loss to the aqueous phase during production. This study demonstrates that, with this technique, polymer microspheres containing explosives can be produced with sufficient encapsulation, along with tightly controlled particle size distributions at high production rates. These microspheres have proven to be a valuable test material for trace explosive detectors because of their highly precise size, shape and explosive composition.

  7. A Design, Fabrication and Test of a Precision Positioning Servo Drive for a Multiplexed Imaging System

    DTIC Science & Technology

    1991-09-01

    ORGANIZATION (if applicable) Navy Postgraduate School PH/Dv Naval Postgraduate School 6c. ADDRESS (City, State , and ZIPCode) 7b ADDRESS (City. State , and ZIP...ORGANIZATION (If applicable) 8C. ADDRESS (City, State , and ZIP Code) 10 SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT ELEMENT NO NO NO...Fabrication and Test of a Precision Positioning Servo Drive for a Multiplexed Imaging System by Joseph Patrick Sargent Jr. Lieutenant, United States Coast

  8. LOW RESISTANCE JUNCTIONS IN CRAYFISH

    PubMed Central

    Peracchia, Camillo

    1973-01-01

    The ultrastructure of low resistance junctions between segments of lateral giant fibers in crayfish is studied in sections from specimens fixed either by conventional methods or by glutaraldehyde-H2O2 or by glutaraldehyde-lanthanum. Cross sections through junctions fixed by conventional glutaraldehyde display the usual trilaminar profile of two parallel membranes separated by a narrow gap. Most of the junctional regions appear covered by 500–800 Å vesicles which lie on both sides of the junction in rows adjacent to the membranes. Gross sections through junctions fixed by glutaraldehyde-H2O2 display, in regions containing vesicles, membranes with a beaded profile. The beads correspond to globules ∼125 Å in width and ∼170 Å in height arranged in a hexagonal pattern with a unit cell of ∼200 Å. The globules of one membrane match precisely with those of the adjacent membrane, and opposite globules seem to come in contact with each other at the center of the junction. The membrane of the vesicles also contains globules. Occasionally the globules of the vesicles seem to join with those of the junctional membranes, apparently forming intracellular junctions. Injunctions negatively stained by lanthanum the globules are seen organized into two arrangements. Areas containing globules in a hexagonal array with a unit cell of ∼200 Å (swollen pattern) are seen adjacent to areas in which the globules are more closely and disorderly packed (close packing), the minimum center-to-center distance between adjacent globules being ∼125 Å. At higher magnification each globule appears composed of six subunits arranged in a circle around a central region occupied by lanthanum (possibly a pit). PMID:4120610

  9. Fabrication and Metrology of High-Precision Foil Mirror Mounting Elements

    NASA Technical Reports Server (NTRS)

    Schattenburg, Mark L.

    2002-01-01

    During the period of this Cooperative Agreement, MIT (Massachusetts Institute of Technology) developed advanced methods for applying silicon microstructures for the precision assembly of foil x-ray optics in support of the Constellation-X Spectroscopy X-ray Telescope (SXT) development effort at Goddard Space Flight Center (GSFC). MIT developed improved methods for fabricating and characterizing the precision silicon micro-combs. MIT also developed and characterized assembly tools and several types of metrology tools in order to characterize and reduce the errors associated with precision assembly of foil optics. Results of this effort were published and presented to the scientific community and the GSFC SXT team. A bibliography of papers and presentations is offered.

  10. Novel fiber Bragg grating fabrication method by high-precision shutter control

    NASA Astrophysics Data System (ADS)

    Liu, Yisi; Gu, Claire; Pan, J. J.; Dong, Liang; Zhou, Feng Q.

    2003-10-01

    Fiber Bragg grating (FBG) is an important element in many applications including filters and dispersion compensators in fiber communication systems. With recently developed inverse scattering algorithm, FBGs with desired reflection spectrum and/or dispersion properties can now be designed. However, most of these designs require arbitrary grating amplitude and phase control. Previously, fabrication of such FBGs relies on the accurate control of the temporal variation of the intensity pattern using a piezo electric translation stage. The precision of this fabrication method is limited by the noise in the control voltage, which is usually larger than 1%. The distortion in piezo response also affects the performance. In this paper, we develop and demonstrate a novel writing technique for arbitrary FBG fabrication. Our technique is based on a translate-and-write configuration. The incorporation of a precisely controlled shutter allows the apodization and phase of the FBG to be continuously changed at each grating line. The shutter error mainly results from the control signal's timing jitter, which is normally lower than 0.1%. Using this writing technique, we demonstrate a Hamming apodized grating with 20mm length, -22 dB minimum transmission, and < -25 dB reflection side lobe suppression. Furthermore, phase-shift in a grating can be fabricated by a simple delay in the control signal. We also demonstrate FBGs with π, π/2, 3π/2 phase-shifts, respectively. Our experimental results are in excellent agreement with theoretical predictions. To show the capability to fabricate a FBG with arbitrary structure, we demonstrate a 35 mm long zero dispersion grating.

  11. Rapid fabrication of a poly(dimethylsiloxane) microfluidic capillary gel electrophoresis system utilizing high precision machining.

    PubMed

    Zhao, Dong S; Roy, Binayak; McCormick, Matthew T; Kuhr, Werner G; Brazill, Sara A

    2003-05-01

    In this work, we demonstrate a rapid protocol to address one of the major barriers that exists in the fabrication of chip devices, creating the micron-sized structures in the substrate material. This approach makes it possible to design, produce, and fabricate a microfluidic system with channel features >10 microm in poly(dimethylsiloxane)(PDMS) in under 8 hours utilizing instrumentation common to most machine shops. The procedure involves the creation of a master template with negative features, using high precision machining. This master is then employed to create an acrylic mold that is used in the final fabrication step to cast channel structures into the PDMS substrate. The performance of the microfluidic system prepared using this fabrication procedure is evaluated by constructing a miniaturized capillary gel electrophoresis (micro-CGE) system for the analysis of DNA fragments. Agarose is utilized as the sieving medium in the micro-CGE device and is shown to give reproducible (RSD (n= 34) approximately 5.0%) results for about 34 individual separations without replenishing the gel. To demonstrate the functionality of the micro-CGE device, a DNA restriction ladder (spanning 26-700 base pairs) and DNA fragments generated by PCR are separated and detected with laser-induced fluorescence (LIF). The microchip is shown to achieve a separation efficiency of 2.53 x 10(5) plates m(-1).

  12. Laser micro-bending for precise micro-fabrication of magnetic disk drive components

    NASA Astrophysics Data System (ADS)

    Matsushita, Naohisa

    2003-11-01

    Laser Micro-Bending technology attracts attention as one of the laser processing technology promising from now on. It has the feature that does not contact and does not have the spring back that fabrication in high accuracy can be performed. In our company, Laser Micro-Bending technology development is tackled about ten years before, and the laser bending fabrication technology of a sheet metal and ceramic material has so far been established. It has utilized as rapid prototyping of the sheet metal. But, by re-examination of laser oscillation control etc., it finds out that it is the excellent processing method for manufacture of the high precision mechanism parts for magnetic disk drives. This report explains the technology and machines of the roll and pitch adjustment of a magnetic head suspension, and flatting or crowning of the air bearing surface of a magnetic head slider by using Laser Micro-Bending technology.

  13. Fabrication of a SFF-based three-dimensional scaffold using a precision deposition system in tissue engineering

    NASA Astrophysics Data System (ADS)

    Kim, Jong Young; Park, Eui Kyun; Kim, Shin-Yoon; Shin, Jung-Woog; Cho, Dong-Woo

    2008-05-01

    Recent developments in tissue-engineering techniques allow physicians to treat a range of previously untreatable conditions. In the development of such techniques, scaffolds with a controllable pore size and porosity have been manufactured using solid free-form fabrication methods to investigate cell interaction effects such as cell proliferation and differentiation. In this study, we describe the fabrication of scaffolds from two types of biodegradable materials using a precision deposition system that we developed. The precision deposition system uses technology that enables the manufacture of three-dimensional (3D) microstructures. The fabrication of 3D tissue-engineering scaffolds using the precision deposition system required the combination of several technologies, including motion control, thermal control, pneumatic control and CAD/CAM software. Through the fabrication and cell interaction analysis of two kinds of scaffolds using polycaprolactone and poly-lactic-co-glycolic acid, feasibility of application to the tissue engineering of the developed SFF-based precision deposition system is demonstrated.

  14. Influence of various gypsum materials on precision of fit of CAD/CAM-fabricated zirconia copings.

    PubMed

    Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Rhee, Hyun-Sill; Lee, Il-Hyun; Kim, Ji-Hwan

    2015-01-01

    The clinical applicability of CAD/CAM-fabricated zirconia copings is tested using working models made from four different highstrength Type IV gypsum materials. Each of the four materials was used to fabricate 15 zirconia copings. Precision of fit was measured with a digital electron microscope using the silicone replica technique. The mean and standard deviation of each reference point were analyzed using the one-way analysis of the variance (ANOVA) and Tukey's honest significant difference (HSD) tests (α=0.05). The overall marginal and internal fits of the zirconia copings were as follows: GS (GS: Grey Stone) group: 91.43 μm, LS (LS: Light green Stone) Group: 87.89 μm, RS (RS: Red Stone) Group: 88.75 μm, BS (BS: Beige Stone) Group: 82.78 μm. There were no significant differences between the mean adaptations of the gypsum varieties (p>0.05). This confirmed that the type of gypsum material used does not determine the precision of fit of a prosthesis.

  15. Sub-nanometer interferometry and precision turning for large optical fabrication

    SciTech Connect

    Klingmann, J L; Sommargren, G E

    1999-04-01

    At Lawrence Livermore National Laboratory (LLNL), we have the unique combination of precision turning and metrology capabilities critical to the fabrication of large optical elements. We have developed a self-referenced interferometer to measure errors in aspheric optics to sub- nanometer accuracy over 200-millimeter apertures, a dynamic range of 5{approximately}10. We have utilized diamond turning to figure optics for X-ray to IR wavelengths and, with fast-tool-servo technology, can move optical segments from off-axis to on-axis. With part capacities to 2.3-meters diameter and the metrology described above, segments of very large, ultra-lightweight mirrors can potentially be figured to final requirements. precision of diamond-turning will carryover although the surface finish may be degraded. Finally, the most critical component of a fabrication process is the metrology that enables an accurate part. Well characterized machines are very repeatable and part accuracy must come from proper metrology. A self- referencing interferometer has been developed that can measure accurately to sub-nanometer values. As with traditional interferometers, measurements are fast and post- processed data provides useful feedback to the user. The simplicity of the device allows it to be used on large optics and systems.

  16. Analysis of the Murine Immune Response to Pulmonary Delivery of Precisely Fabricated Nano- and Microscale Particles

    PubMed Central

    Roberts, Reid A.; Shen, Tammy; Allen, Irving C.; Hasan, Warefta; DeSimone, Joseph M.; Ting, Jenny P. Y.

    2013-01-01

    Nanomedicine has the potential to transform clinical care in the 21st century. However, a precise understanding of how nanomaterial design parameters such as size, shape and composition affect the mammalian immune system is a prerequisite for the realization of nanomedicine's translational promise. Herein, we make use of the recently developed Particle Replication in Non-wetting Template (PRINT) fabrication process to precisely fabricate particles across and the nano- and micro-scale with defined shapes and compositions to address the role of particle design parameters on the murine innate immune response in both in vitro and in vivo settings. We find that particles composed of either the biodegradable polymer poly(lactic-co-glycolic acid) (PLGA) or the biocompatible polymer polyethylene glycol (PEG) do not cause release of pro-inflammatory cytokines nor inflammasome activation in bone marrow-derived macrophages. When instilled into the lungs of mice, particle composition and size can augment the number and type of innate immune cells recruited to the lungs without triggering inflammatory responses as assayed by cytokine release and histopathology. Smaller particles (80×320 nm) are more readily taken up in vivo by monocytes and macrophages than larger particles (6 µm diameter), yet particles of all tested sizes remained in the lungs for up to 7 days without clearance or triggering of host immunity. These results suggest rational design of nanoparticle physical parameters can be used for sustained and localized delivery of therapeutics to the lungs. PMID:23593509

  17. Precision of implementing virtual setups for orthodontic treatment using CAD/CAM-fabricated custom archwires.

    PubMed

    Müller-Hartwich, Ralf; Jost-Brinkmann, Paul-Georg; Schubert, Katharina

    2016-01-01

    The SureSmile® process (OraMetrix®; Richardson, TX, USA) utilizes computer-aided design and computer-aided manufacturing (CAD/CAM). A virtual setup is created for treatment planning and chairside implementation using custom archwires fabricated by robots. The objective of this study was to determine the precision of this implementation. The setup models of 26 consecutive patients were compared to models of the final outcome. Using a virtual matching process, the planned and the achieved tooth positions were superimposed and the differences between them calculated along three translational planes and three rotational axes, thus, yielding six deviation values for each tooth. The median deviations were 0.19-0.21 mm based on translational movements and 1.77°-3.04° based on rotational movements. The precision of implementing the setups decreased from anterior to posterior, with incisors showing the best outcomes. Virtual setups can be implemented in a clinically successful fashion with custom archwires fabricated by CAD/CAM in accordance with the SureSmile® process.

  18. A novel approach for fabrication of single silicon/silicon oxide nanopillars at precise locations

    NASA Astrophysics Data System (ADS)

    Talasila, Sravan Chowdary

    Nanopillars exhibit novel electrical and optical properties which could not be obtained from bulk materials. Many of their practical applications would require controlled placement of nanopillars at exact locations. However, precise placement and large scale fabrication of nanopillars have been challenging with conventional fabrication techniques. This thesis investigates a new approach to fabricate nanopillars at exact locations on a large scale. In this approach, fabrication of nanopillars is accomplished by first placing nanoparticles (NP) at exact locations and then performing anisotropic dry etching using these NPs as hard masks, resulting in formation of nanopillars on exact substrate positions. Precise placement of nanoparticles was carried out by forming an electrostatic guiding template that forces nanoparticles onto site specific locations on the substrate. The electrostatic guiding template was made of a gold layer on SiO2 substrate in which 100nm circular holes are made with underlying SiO2 substrate exposed. The gold substrate surface and exposed SiO2 surface were functionalized with self-assembled monolayers of 16-mercaptohexadecanoic acid (MHA) and 3-aminopropyltriethoxysilane (APTES), producing negatively and positively charged surfaces, respectively. DNA-functionalized Au nanoparticles (negatively charged due to DNA) were used for the nanoparticle hard masks. Guiding of the DNA-functionalized Au nanoparticles to a specific location was conducted by using the electrostatic funneling technique, where the SAMs-functionalized template guided the Au nanoparticles onto center positions of the circular holes. Placement of exactly one single Au nanoparticle at the center of the circular SiO2 exposed area was achieved using self-limiting electrostatic gating, which was controlled by varying ionic and pH concentration of the solution during attachment. Subsequently, with the precise placement of Au nanoparticles, a selective removal of Au deposited layer was

  19. Precise fabrication of a 5 nm graphene nanopore with a helium ion microscope for biomolecule detection

    NASA Astrophysics Data System (ADS)

    Deng, Yunsheng; Huang, Qimeng; Zhao, Yue; Zhou, Daming; Ying, Cuifeng; Wang, Deqiang

    2017-01-01

    We report a scalable method to fabricate high-quality graphene nanopores for biomolecule detection using a helium ion microscope (HIM). HIM milling shows promising capabilities for precisely controlling the size and shape, and may allow for the potential production of nanopores at wafer scale. Nanopores could be fabricated at different sizes ranging from 5 to 30 nm in diameter in few minutes. Compared with the current solid-state nanopore fabrication techniques, e.g. transmission electron microscopy, HIM is fast. Furthermore, we investigated the exposure-time dependence of graphene nanopore formation: the rate of pore expansion did not follow a simple linear relationship with exposure time, but a fast expansion rate at short exposure time and a slow rate at long exposure time. In addition, we performed biomolecule detection with our patterned graphene nanopore. The ionic current signals induced by 20-base single-stranded DNA homopolymers could be used as a basis for homopolymer differentiation. However, the charge interaction of homopolymer chains with graphene nanopores, and the conformations of homopolymer chains need to be further considered to improve the accuracy of discrimination.

  20. Combined fabrication process for high-precision aspheric surface based on smoothing polishing and magnetorheological finishing

    NASA Astrophysics Data System (ADS)

    Nie, Xuqing; Li, Shengyi; Song, Ci; Hu, Hao

    2014-08-01

    Due to the different curvature everywhere, the aspheric surface is hard to achieve high-precision accuracy by the traditional polishing process. Controlling of the mid-spatial frequency errors (MSFR), in particular, is almost unapproachable. In this paper, the combined fabrication process based on the smoothing polishing (SP) and magnetorheological finishing (MRF) is proposed. The pressure distribution of the rigid polishing lap and semi-flexible polishing lap is calculated. The shape preserving capacity and smoothing effect are compared. The feasibility of smoothing aspheric surface with the semi-flexible polishing lap is verified, and the key technologies in the SP process are discussed. Then, A K4 parabolic surface with the diameter of 500mm is fabricated based on the combined fabrication process. A Φ150 mm semi-flexible lap is used in the SP process to control the MSFR, and the deterministic MRF process is applied to figure the surface error. The root mean square (RMS) error of the aspheric surface converges from 0.083λ (λ=632.8 nm) to 0.008λ. The power spectral density (PSD) result shows that the MSFR are well restrained while the surface error has a great convergence.

  1. Precise fabrication of a 5 nm graphene nanopore with a helium ion microscope for biomolecule detection.

    PubMed

    Deng, Yunsheng; Huang, Qimeng; Zhao, Yue; Zhou, Daming; Ying, Cuifeng; Wang, Deqiang

    2017-01-27

    We report a scalable method to fabricate high-quality graphene nanopores for biomolecule detection using a helium ion microscope (HIM). HIM milling shows promising capabilities for precisely controlling the size and shape, and may allow for the potential production of nanopores at wafer scale. Nanopores could be fabricated at different sizes ranging from 5 to 30 nm in diameter in few minutes. Compared with the current solid-state nanopore fabrication techniques, e.g. transmission electron microscopy, HIM is fast. Furthermore, we investigated the exposure-time dependence of graphene nanopore formation: the rate of pore expansion did not follow a simple linear relationship with exposure time, but a fast expansion rate at short exposure time and a slow rate at long exposure time. In addition, we performed biomolecule detection with our patterned graphene nanopore. The ionic current signals induced by 20-base single-stranded DNA homopolymers could be used as a basis for homopolymer differentiation. However, the charge interaction of homopolymer chains with graphene nanopores, and the conformations of homopolymer chains need to be further considered to improve the accuracy of discrimination.

  2. Precision optical asphere fabrication by plasma jet chemical etching (PJCE) and ion beam figuring

    NASA Astrophysics Data System (ADS)

    Schindler, Axel; Boehm, Georg; Haensel, Thomas; Frank, Wilfried; Nickel, Andreas; Rauschenbach, Bernd; Bigl, Frieder

    2001-12-01

    We develop a Plasma Jet Chemical Etching (PJCE) technique for high rate precision machining of optical materials aiming in a technology mature for precision asphere and free-form surface topology fabrication. The present contribution summarizes the achievements after about twelve months experience with a prototype production tool facility. PJCE is performed with the help of a microwave driven reactive plasma-jet working in a broad pressure range (10-600 mbar). We developed a moveable lightweight microwave plasma jet source for dwell time techniques performed in a roughly pumped process chamber equipped with a six axis system for precision workpiece and plasma source movement. Volume etch rates of some 10 mm3/min have been achieved for fused silica and silicon, respectively, using reactive (CF4,SF6,O2) and inert (Ar,He) gas mixtures and applying a microwave (2.45 GHz) power in the 100-200 W range. Large quartz plates (80-160 mm) have been figured using dwell time methods to achieve aspheric deformations of some 10 micrometers . The figured surfaces show shape errors of 1-2 micrometers and a microroughness of 50-100 nm RMS but no sub-surface damage enabling a small tool shape conserving post polishing up to the sub-nanometer roughness level. Thus, surface shaping to the nanometer error range can be done by ion beam finishing.

  3. Micro-optical fabrication by ultraprecision diamond machining and precision molding

    NASA Astrophysics Data System (ADS)

    Li, Hui; Li, Likai; Naples, Neil J.; Roblee, Jeffrey W.; Yi, Allen Y.

    2017-06-01

    Ultraprecision diamond machining and high volume molding for affordable high precision high performance optical elements are becoming a viable process in optical industry for low cost high quality microoptical component manufacturing. In this process, first high precision microoptical molds are fabricated using ultraprecision single point diamond machining followed by high volume production methods such as compression or injection molding. In the last two decades, there have been steady improvements in ultraprecision machine design and performance, particularly with the introduction of both slow tool and fast tool servo. Today optical molds, including freeform surfaces and microlens arrays, are routinely diamond machined to final finish without post machining polishing. For consumers, compression molding or injection molding provide efficient and high quality optics at extremely low cost. In this paper, first ultraprecision machine design and machining processes such as slow tool and fast too servo are described then both compression molding and injection molding of polymer optics are discussed. To implement precision optical manufacturing by molding, numerical modeling can be included in the future as a critical part of the manufacturing process to ensure high product quality.

  4. Fabrication of high precision metallic freeform mirrors with magnetorheological finishing (MRF)

    NASA Astrophysics Data System (ADS)

    Beier, Matthias; Scheiding, Sebastian; Gebhardt, Andreas; Loose, Roman; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas

    2013-09-01

    The fabrication of complex shaped metal mirrors for optical imaging is a classical application area of diamond machining techniques. Aspherical and freeform shaped optical components up to several 100 mm in diameter can be manufactured with high precision in an acceptable amount of time. However, applications are naturally limited to the infrared spectral region due to scatter losses for shorter wavelengths as a result of the remaining periodic diamond turning structure. Achieving diffraction limited performance in the visible spectrum demands for the application of additional polishing steps. Magnetorheological Finishing (MRF) is a powerful tool to improve figure and finish of complex shaped optics at the same time in a single processing step. The application of MRF as a figuring tool for precise metal mirrors is a nontrivial task since the technology was primarily developed for figuring and finishing a variety of other optical materials, such as glasses or glass ceramics. In the presented work, MRF is used as a figuring tool for diamond turned aluminum lightweight mirrors with electroless nickel plating. It is applied as a direct follow-up process after diamond machining of the mirrors. A high precision measurement setup, composed of an interferometer and an advanced Computer Generated Hologram with additional alignment features, allows for precise metrology of the freeform shaped optics in short measuring cycles. Shape deviations less than 150 nm PV / 20 nm rms are achieved reliably for freeform mirrors with apertures of more than 300 mm. Characterization of removable and induced spatial frequencies is carried out by investigating the Power Spectral Density.

  5. Precise broad-band anti-refection coating fabricated by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Li, Yanghui; Shen, Weidong; Zhang, Yueguang; Hao, Xiang; Fan, Huanhuan; Liu, Xu

    2013-04-01

    By demarcating the ranges of transition regions on different underlayers in atomic layer deposition (ALD), their effects on broad-band anti-refection (BBAR) coating (400-680 nm) are evaluated. In ALD, comparatively larger transition region of TiO2 on bare BK7 glass severely limits the fabricated precision of BBAR coating with a thin first layer. Considering that the transition region on existent ALD material is much thinner than that on bare substrate, a thick Al2O3 film is inserted as a pre-deposited layer on the substrate to completely overlay the transition region on bare BK7.A good agreement between the designed and experimental curves is obtained, and its average reflectance is 0.535% (400-680 nm) in practice.

  6. Fabrication of solid-state nanopores with single-nanometre precision.

    PubMed

    Storm, A J; Chen, J H; Ling, X S; Zandbergen, H W; Dekker, C

    2003-08-01

    Single nanometre-sized pores (nanopores) embedded in an insulating membrane are an exciting new class of nanosensors for rapid electrical detection and characterization of biomolecules. Notable examples include alpha-hemolysin protein nanopores in lipid membranes and solid-state nanopores in Si3N4. Here we report a new technique for fabricating silicon oxide nanopores with single-nanometre precision and direct visual feedback, using state-of-the-art silicon technology and transmission electron microscopy. First, a pore of 20 nm is opened in a silicon membrane by using electron-beam lithography and anisotropic etching. After thermal oxidation, the pore can be reduced to a single-nanometre when it is exposed to a high-energy electron beam. This fluidizes the silicon oxide leading to a shrinking of the small hole due to surface tension. When the electron beam is switched off, the material quenches and retains its shape. This technique dramatically increases the level of control in the fabrication of a wide range of nanodevices.

  7. Design and Fabrication of a Precision Template for Spine Surgery Using Selective Laser Melting (SLM).

    PubMed

    Wang, Di; Wang, Yimeng; Wang, Jianhua; Song, Changhui; Yang, Yongqiang; Zhang, Zimian; Lin, Hui; Zhen, Yongqiang; Liao, Suixiang

    2016-07-22

    In order to meet the clinical requirements of spine surgery, this paper proposes the fabrication of the customized template for spine surgery through computer-aided design. A 3D metal printing-selective laser melting (SLM) technique was employed to directly fabricate the 316L stainless steel template, and the metal template with tiny locating holes was used as an auxiliary tool to insert spinal screws inside the patient's body. To guarantee accurate fabrication of the template for cervical vertebra operation, the contact face was placed upwards to improve the joint quality between the template and the cervical vertebra. The joint surface of the printed template had a roughness of Ra = 13 ± 2 μm. After abrasive blasting, the surface roughness was Ra = 7 ± 0.5 μm. The surgical metal template was bound with the 3D-printed Acrylonitrile Butadiene Styrene (ABS) plastic model. The micro-hardness values determined at the cross-sections of SLM-processed samples varied from HV0.3 250 to HV0.3 280, and the measured tensile strength was in the range of 450 MPa to 560 MPa, which showed that the template had requisite strength. Finally, the metal template was clinically used in the patient's surgical operation, and the screws were inserted precisely as the result of using the auxiliary template. The geometrical parameters of the template hole (e.g., diameter and wall thickness) were optimized, and measures were taken to optimize the key geometrical units (e.g., hole units) in metal 3D printing. Compared to the traditional technology of screw insertion, the use of the surgical metal template enabled the screws to be inserted more easily and accurately during spinal surgery. However, the design of the high-quality template should fully take into account the clinical demands of surgeons, as well as the advice of the designing engineers and operating technicians.

  8. Precision tuning of silicon nanophotonic devices through post-fabrication processes

    NASA Astrophysics Data System (ADS)

    Chen, Charlton J.

    In recent years, silicon photonics has begun to transition from research to commercialization. Decades of relentless advances in the field of computing have led to fundamental bottlenecks in the design of computers, especially in interconnect bandwidth density. For IBM, silicon photonics has become a potential technological solution for enabling the future of server systems and cutting-edge supercomputers. For Intel, silicon photonics has become a cost-effective solution for supplying the necessary bandwidth needed by future generations of consumer computing products. While the field of silicon photonics is now advancing at a rapid pace there is still a great deal of research to be done. This thesis investigates ways of improving the performance of fundamental silicon nanophotonic devices through post-fabrication processes. These devices include numerous optical resonator designs as well as slow-light waveguides. Optical resonators are used to confine photons both spatially and temporally. In recent years, there has been much research, both theoretical and experimental, into improving the design of optical resonators. Improving these devices through fabrication processes has generally been less studied. Optical waveguides are used to guide the flow of photons over chip-level distances. Slow-light waveguides have also been studied by many research groups in recent years and can be applied to an increasingly wide-range of applications. The work can be divided into several parts: Chapter 1 is an introduction to the field of silicon photonics as well as an overview of the fabrication, experimental and computational techniques used throughout this work. Chapters 2, 3 and 4 describe our investigations into the precision tuning of nanophotonic devices using laser-assisted thermal oxidation and atomic layer deposition. Chapters 5 and 6 describe our investigations into improving the sidewall roughness of silicon photonic devices using hydrogen annealing and excimer laser

  9. Design and Fabrication of a Precision Template for Spine Surgery Using Selective Laser Melting (SLM)

    PubMed Central

    Wang, Di; Wang, Yimeng; Wang, Jianhua; Song, Changhui; Yang, Yongqiang; Zhang, Zimian; Lin, Hui; Zhen, Yongqiang; Liao, Suixiang

    2016-01-01

    In order to meet the clinical requirements of spine surgery, this paper proposes the fabrication of the customized template for spine surgery through computer-aided design. A 3D metal printing-selective laser melting (SLM) technique was employed to directly fabricate the 316L stainless steel template, and the metal template with tiny locating holes was used as an auxiliary tool to insert spinal screws inside the patient’s body. To guarantee accurate fabrication of the template for cervical vertebra operation, the contact face was placed upwards to improve the joint quality between the template and the cervical vertebra. The joint surface of the printed template had a roughness of Ra = 13 ± 2 μm. After abrasive blasting, the surface roughness was Ra = 7 ± 0.5 μm. The surgical metal template was bound with the 3D-printed Acrylonitrile Butadiene Styrene (ABS) plastic model. The micro-hardness values determined at the cross-sections of SLM-processed samples varied from HV0.3 250 to HV0.3 280, and the measured tensile strength was in the range of 450 MPa to 560 MPa, which showed that the template had requisite strength. Finally, the metal template was clinically used in the patient’s surgical operation, and the screws were inserted precisely as the result of using the auxiliary template. The geometrical parameters of the template hole (e.g., diameter and wall thickness) were optimized, and measures were taken to optimize the key geometrical units (e.g., hole units) in metal 3D printing. Compared to the traditional technology of screw insertion, the use of the surgical metal template enabled the screws to be inserted more easily and accurately during spinal surgery. However, the design of the high-quality template should fully take into account the clinical demands of surgeons, as well as the advice of the designing engineers and operating technicians. PMID:28773730

  10. Precision Extruding Deposition for Freeform Fabrication of PCL and PCL-HA Tissue Scaffolds

    NASA Astrophysics Data System (ADS)

    Shor, L.; Yildirim, E. D.; Güçeri, S.; Sun, W.

    Computer-aided tissue engineering approach was used to develop a novel Precision Extrusion Deposition (PED) process to directly fabricate Polycaprolactone (PCL) and composite PCL/Hydroxyapatite (PCL-HA) tissue scaffolds. The process optimization was carried out to fabricate both PCL and PCL-HA (25% concentration by weight of HA) with a controlled pore size and internal pore structure of the 0°/90° pattern. Two groups of scaffolds having 60 and 70% porosity and with pore sizes of 450 and 750 microns, respectively, were evaluated for their morphology and compressive properties using Scanning Electron Microscopy (SEM) and mechanical testing. The surface modification with plasma was conducted on PCL scaffold to increase the cellular attachment and proliferation. Our results suggested that inclusion of HA significantly increased the compressive modulus from 59 to 84 MPa for 60% porous scaffolds and from 30 to 76 MPa for 70% porous scaffolds. In vitro cell-scaffolds interaction study was carried out using primary fetal bovine osteoblasts to assess the feasibility of scaffolds for bone tissue engineering application. In addition, the results in surface hydrophilicity and roughness show that plasma surface modification can increase the hydrophilicity while introducing the nano-scale surface roughness on PCL surface. The cell proliferation and differentiation were calculated by Alamar Blue assay and by determining alkaline phosphatase activity. The osteoblasts were able to migrate and proliferate over the cultured time for both PCL as well as PCL-HA scaffolds. Our study demonstrated the viability of the PED process to the fabricate PCL and PCL-HA composite scaffolds having necessary mechanical property, structural integrity, controlled pore size and pore interconnectivity desired for bone tissue engineering.

  11. High-precision micromilling for low-cost fabrication of metal mold masters

    NASA Astrophysics Data System (ADS)

    Hupert, Mateusz L.; Guy, W. J.; Llopis, Shawn D.; Situma, Catherine; Rani, Sudheer; Nikitopoulos, Dimitris E.; Soper, Steven A.

    2006-01-01

    High-precision micromilling was employed as a cost-efficient method preparation of metal masters useful in fabrication of polymer microfluidic devices through replication techniques. In first application, a brass mold master was used for hot embossing of microchip electrophoresis devices in poly(methyl methacrylate) (PMMA). The sidewalls of the milled microstructures were characterized by a maximum average roughness (R a) of 110 nm and mean peak height (R pm) of 320 nm. SEM imaging showed a transfer of the sidewall roughness from the molding tool to the polymer microdevice. The electroosmotic flow (EOF) values for micromilled-based microchannels were comparable to ones in the LiGA-prepared devices (sidewall R a = 20 nm) with values of ca. 3.7 x 10 -4 cm2V -1s -1 (20 mM TBE buffer, pH 8.2), indicating insignificant effects of wall roughness on the bulk EOF. Numerical simulations showed that the additional volumes present in an injection cross due to curvature of the corners produced by micromilling lead to elongated sample plugs. PMMA microchip electrophoresis devices were used for a separation of pUC19 Sau3AI double-stranded DNA. The plate numbers achieved exceeded 1 million m -1 and were comparable to the plate numbers for the LiGA-based devices of similar geometry. In second application brass master was used as tool for preparation of poly(dimethylsiloxane) PDMS stencils for patterning of DNA microarrays onto a PMMA substrate. Four zip code probes immobilized onto the PMMA surface directed allele-specic ligation products containing mutations in the KRAS2 gene (12.2D, 12.2A, 12.2V, and 13.4D) to the appropriate address of a universal array with minimal amounts of crosshybridization or misligation.

  12. Fabrication of a wide-field NIR integral field unit for SWIMS using ultra-precision cutting

    NASA Astrophysics Data System (ADS)

    Kitagawa, Yutaro; Yamagata, Yutaka; Morita, Shin-ya; Motohara, Kentaro; Ozaki, Shinobu; Takahashi, Hidenori; Konishi, Masahiro; Kato, Natsuko M.; Kobayakawa, Yutaka; Terao, Yasunori; Ohashi, Hirofumi

    2016-07-01

    We describe overview of fabrication methods and measurement results of test fabrications of optical surfaces for an integral field unit (IFU) for Simultaneous color Wide-field Infrared Multi-object Spectrograph, SWIMS, which is a first-generation instrument for the University of Tokyo Atacama Observatory 6.5-m telescope. SWIMS-IFU provides entire near-infrared spectrum from 0.9 to 2.5 μm simultaneously covering wider field of view of 17" × 13" compared with current near-infrared IFUs. We investigate an ultra-precision cutting technique to monolithically fabricate optical surfaces of IFU optics such as an image slicer. Using 4- or 5-axis ultra precision machine we compare the milling process and shaper cutting process to find the best way of fabrication of image slicers. The measurement results show that the surface roughness almost satisfies our requirement in both of two methods. Moreover, we also obtain ideal surface form in the shaper cutting process. This method will be adopted to other mirror arrays (i.e. pupil mirror and slit mirror, and such monolithic fabrications will also help us to considerably reduce alignment procedure of each optical elements.

  13. Low resistivity, low contrast pays

    SciTech Connect

    Sneider, R.M.; Kulha, J.T. |

    1996-08-01

    Major hydrocarbon accumulations have been produced over the past 40 years in low resistivity, low contrast (LRLC) sands in the Gulf of Mexico Basin (GOM). LRLC reservoirs were commonly considered wet, tight, misidentified as a shale or overlooked, but are being re-evaluated now in other world basins, including Latin America. Seismic response, drill cuttings, cores, log response, petrophysical models, and production testing provide an integrated LRLC evaluation. Causes of LRLC pay in the GOM include: laminated clean sands with shales; silts or shaly sands; clay-coated sands; glauconitic sands; sands with interstitial dispersed clay; sands with disseminated pyrite or other conductive minerals; clay-lined burrows; clay clasts; altered volcanic/feldspathic framework grains; and very fine-grained sand with very saline water. LRLC depositional systems include: deepwater fans, with levee-channel complexes; delta front and toe deposits; shingle turbidites; and alluvial and deltaic channel fills. Geological and petrophysical models developed in the GOM for evaluation of LRLC pay are applicable in Latin America. An Archie clean sand or Waxman-Smits shaly sand model are commonly used to evaluate LRLC anomalies. Often, shaly sand models are not necessarily suited for LRLC evaluation. The Archie lithology exponent (m) and saturation exponent (n) for many LRLC reservoirs range from 1.4 to 1.85, and 1.2 to 1.8, respectively. In thinly laminated LRLC reservoirs, net sand distribution is identified with high resolution logging tools, rock examination and interval testing.

  14. LOW RESISTANCE JUNCTIONS IN CRAYFISH

    PubMed Central

    Peracchia, Camillo

    1973-01-01

    Low resistance junctions between axons of crayfish ganglia are studied by freeze-fracture and negative staining. In freeze-fracture, fracture planes that go through a junctional membrane expose two faces, both internal, called face A and face B. Face A belongs to the internal membrane leaflet and faces the gap. Face B belongs to the external membrane leaflet and faces the axoplasm. Face A displays pits, 60–100 Å in diameter, arranged in a hexagonal array with a unit cell of ∼200 Å. An ∼25 Å bump is frequently seen at the center of each pit. Some pits are occupied by a globule ∼125 Å in diameter, which displays a central depression ∼25 Å in size. Face B contains globules also arranged in a fairly regular hexagonal pattern. The center-to-center distance between adjacent globules is most frequently ∼200 Å; however, occasionally certain globules are seen separated by a distance as short as ∼125 Å. The top surface of the globules occasionally displays a starlike profile and seems to contain a central depression ∼25 Å in diameter. In negatively stained preparations of membranes from the nerve cord, two types of membranes are seen containing a fairly regular pattern. In one, globules ∼95 Å in diameter form a hexagonal close packing with a unit cell of ∼95 Å. In the other, globules of the same size are organized in a larger hexagonal array with a unit cell of ∼155 Å (swollen arrangement). Some of the globules forming the swollen arrangement are seen containing six subunits. The six subunits form a hexagon which is skewed with respect to the main rows of hexagons in such a way that the subunits lie on rows which make an angle of ∼37° with the main rows. PMID:4120611

  15. High-precision, large-domain three-dimensional manipulation of nano-materials for fabrication nanodevices

    PubMed Central

    2011-01-01

    Nanoscaled materials are attractive building blocks for hierarchical assembly of functional nanodevices, which exhibit diverse performances and simultaneous functions. We innovatively fabricated semiconductor nano-probes of tapered ZnS nanowires through melting and solidifying by electro-thermal process; and then, as-prepared nano-probes can manipulate nanomaterials including semiconductor/metal nanowires and nanoparticles through sufficiently electrostatic force to the desired location without structurally and functionally damage. With some advantages of high precision and large domain, we can move and position and interconnect individual nanowires for contracting nanodevices. Interestingly, by the manipulating technique, the nanodevice made of three vertically interconnecting nanowires, i.e., diode, was realized and showed an excellent electrical property. This technique may be useful to fabricate electronic devices based on the nanowires' moving, positioning, and interconnecting and may overcome fundamental limitations of conventional mechanical fabrication. PMID:21794151

  16. Improvements in ICF target fabrication through high precision assembly and nondestructive characterization

    SciTech Connect

    Obrey, Kimberly Ann Defriend; Schmidt, Derek W; Patterson, Brian M; Day, Robert D; Valdez, Adelaida C; Capelli, Deanna; Perea, Ron; Randolph, Blaine; Hatch, Doug; Garcia, Felix; Honnell, Diana

    2009-01-01

    Current ICF and HED targets are fielded on Omega, Z, and Trident, and future campaigns will be fielded on NIF. NIF will only field less than 2 shots per day. With such few experiments, target fabrication and target alignment accuracy, enhanced metrology and advanced component machining will be even more important. Future target designs are also becoming more complex and more stringent in terms of accuracy. Several steps have been taken to improve the fabrication and characterization of targets, such as instituting an automated assembly station with 3 mm tolerances, utilizing nondestructive characterization tools for rapid component metrology and target assembly, and advancing machining capabilities. Recapitalization of target fabrication infrastructure is continuous.

  17. Evaluation of the growth of chondrocytes and osteoblasts seeded into precision scaffolds fabricated by fused deposition manufacturing.

    PubMed

    Hsu, Shan-hui; Yen, Hung-Jen; Tseng, Ching-Shiow; Cheng, Chia-Sheng; Tsai, Ching-Lin

    2007-02-01

    In this study, fused deposition manufacturing (FDM) was utilized to fabricate the precision scaffolds for cartilage and bone regeneration. Cell seeding into such scaffolds was evaluated. For poly(D,l-lactide) (PLA) scaffolds used for cartilage regeneration, the structure with larger inner space, four direction stacking (4D) and small interval of fibers were better. Chondrocyte proliferated well with matrix accumulation in precision scaffolds coated with type II collagen at 4 weeks of in vitro culture. The seeding efficiency of osteoblasts in most polycaprolactone (PCL) scaffolds used for bone regeneration could arrive 50% of original cell seeding density, and the amount of cells in scaffolds increased to double fold after 2 weeks of in vitro culture. The histological cross-section also revealed proliferation and mineralization of osteoblasts among the PCL fibers. The results indicated that the highly porous and interconnected structure of precision scaffolds could benefit cell ingrowth.

  18. Atomic Precision Donor Devices Fabricated on Strained Silicon on Insulator (sSOI) with SiGe

    NASA Astrophysics Data System (ADS)

    Yitamben, E.; Bussmann, E.; Scrymgeour, D. A.; Rudolph, M.; Carr, S. M.; Ward, D. R.; Carroll, M. S.

    Recently, Si:P donor spin qubits have achieved coherence times (nuclear & e-) that underscore their quantum computing potential. One next major challenge is to integrate donors into a gated structure where electrons can be moved between P, or drawn off of the P to interact, e.g. to an interface as in Kane's proposal. A key constraint is limited thermal budget, to limit P thermal segregation, which precludes typical gate oxidation of Si. We are developing an alternative materials stack utilizing an interfacial barrier layer of relaxed epitaxial SiGe, with donors placed in a strained Si-on-insulator (sSOI) substrate. We fabricate atomic precision donor structures in sSOI via STM hydrogen lithography. Utilizing Si microfabrication and STM in tandem with our Si and Ge molecular beam epitaxy (MBE), we fabricated devices to test our SiGe/sSOI stack concept and atomic-precision fab techniques. To establish our donor-doping capability, we made Hall and Van der Pauw devices in P:sSOI delta-doped layers exhibiting ne >1014/cm2 and mobilities of ~100 cm2/Vs (T =4K) similar to results reported relaxed Si reported elsewhere. Second, we have grown our concept epitaxial SiGe/sSOI stack, evaluated the morphology using STM, and fabricated Hall devices to evaluate low-T transport in our first SiGe/sSOI. Here, we report on these advances in atomic precision donor fab, along with STM analysis our MBE SiGe/sSOI. This work extends STM-based atom precision fab on strained Si toward a vertically gated architecture.

  19. High-precision flexible fabrication of tissue engineering scaffolds using distinct polymers

    SciTech Connect

    Wei, Chuang; Cai, Lei; Sonawane, Bhushan; Wang, Shanfeng; Dong, Jingyan

    2012-01-01

    Three-dimensional porous structures using biodegradable materials with excellent biocompatibility are critically important for tissue engineering applications. We present a multi-nozzle-based versatile deposition approach to flexibly construct porous tissue engineering scaffolds using distinct polymeric biomaterials such as thermoplastic and photo-crosslinkable polymers. We first describe the development of the deposition system and fabrication of scaffolds from two types of biodegradable polymers using this system. The thermoplastic sample is semi-crystalline poly({var_epsilon}-caprolactone) (PCL) that can be processed at a temperature higher than its melting point and solidifies at room temperature. The photo-crosslinkable one is polypropylene fumarate (PPF) that has to be dissolved in a reactive solvent as a resin for being cured into solid structures. Besides the direct fabrication of thermoplastic PCL scaffolds, we specifically develop a layer molding approach for the fabrication of crosslinkable polymers, which traditionally can only be fabricated by stereolithography. In this approach, a thermoplastic supporting material (paraffin wax) is first deposited to make a mold for each specific layer, and then PPF is deposited on demand to fill the mold and cured by the UV light. The supporting material can be removed to produce a porous scaffold of crosslinked PPF. Both PCL and crosslinked PPF scaffolds fabricated using the developed system have been characterized in terms of compressive mechanical properties, morphology, pore size and porosity. Mouse MC3T3-E1 pre-osteoblastic cell studies on the fabricated scaffolds have been performed to demonstrate their capability of supporting cell proliferation and ingrowth, aiming for bone tissue engineering applications.

  20. High-precision flexible fabrication of tissue engineering scaffolds using distinct polymers.

    PubMed

    Wei, Chuang; Cai, Lei; Sonawane, Bhushan; Wang, Shanfeng; Dong, Jingyan

    2012-06-01

    Three-dimensional porous structures using biodegradable materials with excellent biocompatibility are critically important for tissue engineering applications. We present a multi-nozzle-based versatile deposition approach to flexibly construct porous tissue engineering scaffolds using distinct polymeric biomaterials such as thermoplastic and photo-crosslinkable polymers. We first describe the development of the deposition system and fabrication of scaffolds from two types of biodegradable polymers using this system. The thermoplastic sample is semi-crystalline poly(ε-caprolactone) (PCL) that can be processed at a temperature higher than its melting point and solidifies at room temperature. The photo-crosslinkable one is polypropylene fumarate (PPF) that has to be dissolved in a reactive solvent as a resin for being cured into solid structures. Besides the direct fabrication of thermoplastic PCL scaffolds, we specifically develop a layer molding approach for the fabrication of crosslinkable polymers, which traditionally can only be fabricated by stereolithography. In this approach, a thermoplastic supporting material (paraffin wax) is first deposited to make a mold for each specific layer, and then PPF is deposited on demand to fill the mold and cured by the UV light. The supporting material can be removed to produce a porous scaffold of crosslinked PPF. Both PCL and crosslinked PPF scaffolds fabricated using the developed system have been characterized in terms of compressive mechanical properties, morphology, pore size and porosity. Mouse MC3T3-E1 pre-osteoblastic cell studies on the fabricated scaffolds have been performed to demonstrate their capability of supporting cell proliferation and ingrowth, aiming for bone tissue engineering applications.

  1. Precise electrochemical fabrication of sub-20 nm solid-state nanopores for single-molecule biosensing.

    PubMed

    Ayub, Mariam; Ivanov, Aleksandar; Hong, Jongin; Kuhn, Phillip; Instuli, Emanuele; Edel, Joshua B; Albrecht, Tim

    2010-11-17

    It has recently been shown that solid-state nanometer-scale pores ('nanopores') can be used as highly sensitive single-molecule sensors. For example, electrophoretic translocation of DNA, RNA and proteins through such nanopores has enabled both detection and structural analysis of these complex biomolecules. Control over the nanopore size is critical as the pore must be comparable in size to the analyte molecule in question. The most widely used fabrication methods are based on focused electron or ion beams and thus require (scanning) transmission electron microscopy and focused ion beam (FIB) instrumentation. Even though very small pores have been made using these approaches, several issues remain. These include the requirement of being restricted to rather thin, mechanically less stable membranes, particularly for pore diameters in the single-digit nanometer range, lack of control of the surface properties at and inside the nanopore, and finally, the fabrication cost. In the proof-of-concept study, we report on a novel and simple route for fabricating metal nanopores with apparent diameters below 20 nm using electrodeposition and real-time ionic current feedback in solution. This fabrication approach inserts considerable flexibility into the kinds of platforms that can be used and the nanopore membrane material. Starting from much larger pores, which are straightforward to make using FIB or other semiconductor fabrication methods, we electrodeposit Pt at the nanopore interface while monitoring its ionic conductance at the same time in a bi-potentiostatic setup. Due to the deposition of Pt, the nanopore decreases in size, resulting in a decrease of the pore conductance. Once a desired pore conductance has been reached, the electrodeposition process is stopped by switching the potential of the membrane electrode and the fabrication process is complete. Furthermore, we demonstrate that these pores can be used for single-biomolecule analysis, such as that of

  2. Precise electrochemical fabrication of sub-20 nm solid-state nanopores for single-molecule biosensing

    NASA Astrophysics Data System (ADS)

    Ayub, Mariam; Ivanov, Aleksandar; Hong, Jongin; Kuhn, Phillip; Instuli, Emanuele; Edel, Joshua B.; Albrecht, Tim

    2010-11-01

    It has recently been shown that solid-state nanometer-scale pores ('nanopores') can be used as highly sensitive single-molecule sensors. For example, electrophoretic translocation of DNA, RNA and proteins through such nanopores has enabled both detection and structural analysis of these complex biomolecules. Control over the nanopore size is critical as the pore must be comparable in size to the analyte molecule in question. The most widely used fabrication methods are based on focused electron or ion beams and thus require (scanning) transmission electron microscopy and focused ion beam (FIB) instrumentation. Even though very small pores have been made using these approaches, several issues remain. These include the requirement of being restricted to rather thin, mechanically less stable membranes, particularly for pore diameters in the single-digit nanometer range, lack of control of the surface properties at and inside the nanopore, and finally, the fabrication cost. In the proof-of-concept study, we report on a novel and simple route for fabricating metal nanopores with apparent diameters below 20 nm using electrodeposition and real-time ionic current feedback in solution. This fabrication approach inserts considerable flexibility into the kinds of platforms that can be used and the nanopore membrane material. Starting from much larger pores, which are straightforward to make using FIB or other semiconductor fabrication methods, we electrodeposit Pt at the nanopore interface while monitoring its ionic conductance at the same time in a bi-potentiostatic setup. Due to the deposition of Pt, the nanopore decreases in size, resulting in a decrease of the pore conductance. Once a desired pore conductance has been reached, the electrodeposition process is stopped by switching the potential of the membrane electrode and the fabrication process is complete. Furthermore, we demonstrate that these pores can be used for single-biomolecule analysis, such as that of

  3. Fabrication of precision high quality facets on molecular beam epitaxy material

    DOEpatents

    Petersen, Holly E.; Goward, William D.; Dijaili, Sol P.

    2001-01-01

    Fabricating mirrored vertical surfaces on semiconductor layered material grown by molecular beam epitaxy (MBE). Low energy chemically assisted ion beam etching (CAIBE) is employed to prepare mirrored vertical surfaces on MBE-grown III-V materials under unusually low concentrations of oxygen in evacuated etching atmospheres of chlorine and xenon ion beams. UV-stabilized smooth-surfaced photoresist materials contribute to highly vertical, high quality mirrored surfaces during the etching.

  4. Study on optical fabrication and metrology of precise convex aspheric mirror

    NASA Astrophysics Data System (ADS)

    Wang, Huijun; Xu, Jin; Wang, Peng; Li, Ang; Guo, Wen; Du, Yan

    2016-10-01

    Optical fabrication and metrology technologies are studied in the paper to improve the accuracy of surface figure of a convex aspheric mirror. First, the main specifications of a convex aspheric mirror which is chosen to be the secondary mirror of an optical system are presented. The aperture of the mirror is 400mm. The mirror is made of ultra-low expansion (ULE) glass with honeycomb sandwich structure to get the ideal lightweight requirement. Then the mirror is surfaced by ultrasonic grinding, smart robot lapping and smart robot polishing processes relatively. Large-apertured tool is applied to reduce the mid-frequency surface error. Both the contour measuring method in the grinding and lapping stage and the measuring method with meniscus lens and its calibration mirror in the polishing stage are studied. The final surface figure of the mirror is that the root mean-square value (RMS value) is 0.016λ (λ=632.8nm), which meets the requirement of the optical system. The results show that the forging surfacing processes and measuring methods are accurate and efficient to fabricate the convex aspheric mirror and can be applied in optical fabrication for larger-apertured convex aspheric mirrors.

  5. Brazed Diamond Micropowder Bur Fabricated by Supersonic Frequency Induction Heating for Precision Machining

    NASA Astrophysics Data System (ADS)

    Ma, Bojiang; Lou, Jianpeng; Pang, Qian

    2014-04-01

    The common brazed diamond micropowder bur fabricated in a vacuum furnace produces an even brazing alloy surface. The small brazed diamond grits show low outcropping from the brazing alloy surface, and the chip space between them is small. The bur shows a low grinding efficiency and poor heat dissipation. In this study, a brazed diamond micropowder bur was fabricated by supersonic frequency induction heating. The method afforded a fluctuant surface on the brazing alloy. The brazed diamond grits with an outcropping height distributed uniformly on the fluctuant surface. The fluctuant surface showed a certain chip space. These characteristics of the tool increased the grinding efficiency and decreased the temperature of the grinding arc area. The roughness R a of the ceramic tile surface trimmed by the tool cylinder was between 0.09 and 0.12 μm. In the first 90 min, the decrease in the weight of the ceramic tile ground by the tool cylinder was higher than that ground by the tool fabricated in a vacuum furnace. When the ceramic tile was cylindrically ground, the temperature of the grinding arc area measured using a thermocouple remained below 70 °C.

  6. Dynamic metrology and data processing for precision freeform optics fabrication and testing

    NASA Astrophysics Data System (ADS)

    Aftab, Maham; Trumper, Isaac; Huang, Lei; Choi, Heejoo; Zhao, Wenchuan; Graves, Logan; Oh, Chang Jin; Kim, Dae Wook

    2017-06-01

    Dynamic metrology holds the key to overcoming several challenging limitations of conventional optical metrology, especially with regards to precision freeform optical elements. We present two dynamic metrology systems: 1) adaptive interferometric null testing; and 2) instantaneous phase shifting deflectometry, along with an overview of a gradient data processing and surface reconstruction technique. The adaptive null testing method, utilizing a deformable mirror, adopts a stochastic parallel gradient descent search algorithm in order to dynamically create a null testing condition for unknown freeform optics. The single-shot deflectometry system implemented on an iPhone uses a multiplexed display pattern to enable dynamic measurements of time-varying optical components or optics in vibration. Experimental data, measurement accuracy / precision, and data processing algorithms are discussed.

  7. Effect of preparation angles on the precision of zirconia crown copings fabricated by CAD/CAM system.

    PubMed

    Beuer, Florian; Edelhoff, Daniel; Gernet, Wolfgang; Naumann, Michael

    2008-11-01

    The aim of this in vitro study was to evaluate the effects of different preparation angles on the precision of fit of zirconia crown frameworks. Dies were fabricated with three different preparation angles: 4, 8, and 12 degrees total taper. Ten copings were fabricated for each angle by a laboratory and a milling-center CAD/CAM system. After cementation, cross-sections were obtained and cement gaps were measured. Preparation angle (ANOVA, p < 0.01) and measurement location (ANOVA, p < 0.01) exhibited statistically significant influence on the precision of fit. On the other hand, no statistically significant influences were detected between copings prepared using the laboratory and milling-center CAD/CAM systems (ANOVA, p = 0.92). All groups showed marginal openings ranging between 36.6 and 45.5 microm. In light of the results obtained in this study, a preparation angle of 12 degrees is hence recommended with the confidence that the marginal gap will be consistently less than 50 microm.

  8. Damage coefficients in low resistivity silicon. [solar cells

    NASA Technical Reports Server (NTRS)

    Srour, J. R.; Othmer, S.; Chiu, K. Y.; Curtis, O. L., Jr.

    1975-01-01

    Electron and proton damage coefficients are determined for low resistivity silicon based on minority-carrier lifetime measurements on bulk material and diffusion length measurements on solar cells. Irradiations were performed on bulk samples and cells fabricated from four types of boron-doped 0.1 ohm-cm silicon ingots, including the four possible combinations of high and low oxygen content and high and low dislocation density. Measurements were also made on higher resistivity boron-doped bulk samples and solar cells. Major observations and conclusions from the investigation are discussed.

  9. Rugged Low-Resistance Contacts To High-Tc Superconductors

    NASA Technical Reports Server (NTRS)

    Caton, Randall; Selim, Raouf; Byvik, Charles E.; Buoncristiani, A. Martin

    1992-01-01

    Newly developed technique involving use of gold makes possible to fabricate low-resistance contacts with rugged connections to high-Tc superconductors. Gold diffused into specimen of superconducting material by melting gold beads onto surface of specimen, making strong mechanical contacts. Shear strength of gold bead contacts greater than epoxy or silver paste. Practical use in high-current-carrying applications of new high-Tc materials, including superconducting magnets, long-wavelength sensors, electrical ground planes at low temperatures, and efficient transmission of power.

  10. Rugged Low-Resistance Contacts To High-Tc Superconductors

    NASA Technical Reports Server (NTRS)

    Caton, Randall; Selim, Raouf; Byvik, Charles E.; Buoncristiani, A. Martin

    1992-01-01

    Newly developed technique involving use of gold makes possible to fabricate low-resistance contacts with rugged connections to high-Tc superconductors. Gold diffused into specimen of superconducting material by melting gold beads onto surface of specimen, making strong mechanical contacts. Shear strength of gold bead contacts greater than epoxy or silver paste. Practical use in high-current-carrying applications of new high-Tc materials, including superconducting magnets, long-wavelength sensors, electrical ground planes at low temperatures, and efficient transmission of power.

  11. A study on ultra-precision machining technique for Al6061-T6 to fabricate space infrared optics

    NASA Astrophysics Data System (ADS)

    Ryu, Geun-man; Lee, Gil-jae; Hyun, Sang-won; Sung, Ha-yeong; Chung, Euisik; Kim, Geon-hee

    2014-08-01

    In this paper, analysis of variance on designed experiments with full factorial design was applied to determine the optimized machining parameters for ultra-precision fabrication of the secondary aspheric mirror, which is one of the key elements of the space cryogenic infrared optics. A single point diamond turning machine (SPDTM, Nanotech 4μpL Moore) was adopted to fabricate the material, AL6061-T6, and the three machining parameters of cutting speed, feed rate and depth of cut were selected. With several randomly assigned experimental conditions, surface roughness of each condition was measured by a non-contact optical profiler (NT2000; Vecco). As a result of analysis using Minitab, the optimum cutting condition was determined as following; cutting speed: 122 m/min, feed rate: 3 mm/min and depth of cut: 1 μm. Finally, a 120 mm diameter aspheric secondary mirror was attached to a particularly designed jig by using mixture of paraffin and wax and successfully fabricated under the optimum machining parameters. The profile of machined surface was measured by a high-accuracy 3-D profilometer(UA3P; Panasonic) and we obtained the geometrical errors of 30.6 nm(RMS) and 262.4 nm(PV), which satisfy the requirements of the space cryogenic infrared optics.

  12. Lithography and doping in strained Si towards atomically precise device fabrication.

    PubMed

    Lee, W C T; McKibbin, S R; Thompson, D L; Xue, K; Scappucci, G; Bishop, N; Celler, G K; Carroll, M S; Simmons, M Y

    2014-04-11

    We investigate the ability to introduce strain into atomic-scale silicon device fabrication by performing hydrogen lithography and creating electrically active phosphorus δ-doped silicon on strained silicon-on-insulator (sSOI) substrates. Lithographic patterns were obtained by selectively desorbing hydrogen atoms from a H resist layer adsorbed on a clean, atomically flat sSOI(001) surface with a scanning tunnelling microscope tip operating in ultra-high vacuum. The influence of the tip-to-sample bias on the lithographic process was investigated allowing us to pattern feature-sizes from several microns down to 1.3 nm. In parallel we have investigated the impact of strain on the electrical properties of P:Si δ-doped layers. Despite the presence of strain inducing surface variations in the silicon substrate we still achieve high carrier densities (>1.0 × 10(14) cm(-2)) with mobilities of ∼100 cm(2) V(-1) s(-1). These results open up the possibility of a scanning-probe lithography approach to the fabrication of strained atomic-scale devices in silicon.

  13. High-precision robotic equatorial C-ring telescope mounts: design, fabrication, and performance

    NASA Astrophysics Data System (ADS)

    Dubberley, Matthew A.

    2010-07-01

    The performance of the C-ring telescope mount rivals other designs in stiffness, tracking, simplicity, lack of field rotation, mechanical size and operating envelope. Issues relating to cost, fabrication, and complexity have suppressed the prevalence of the C-ring mount. The Las Cumbres Observatory Global Telescope (LCOGT) robotic C-ring telescope mounts, built for its network of 1.0m and 0.4m telescopes, solve many of these issues. The design yields a scalable mount with performance capabilities well suited for telescopes located at the best astronomical sites in the world at a low cost. Pointing has been demonstrated to be under 7 arc-sec RMS. Unguided tracking performance is 0.6 arc-sec for 1 minute and 2 arc-sec for 15 minutes. Slew speeds of 10deg/sec are reliably used with sub-second settling times. The mount coupled with the 1.0m telescope yields a well damped 16 Hz system. Axes are driven with zero backlash direct drive motors with a 0.01 arc-sec resolution. High system bandwidth yields superb disturbance rejection making it ideal for open air operation. Drive and bearings are maintenance free and feature a novel "bug cover" to seal them from wear and damage. Low costs are achieved with the drive/feedback configuration, structure design, and fabrication techniques, as well minimizing operating and maintenance.

  14. Improvement of distortion error for fabricating precision microparts using two-photon photopolymerization

    NASA Astrophysics Data System (ADS)

    Kim, Jung-Dae; Lee, Yong-Gu

    2016-07-01

    The manufacturing accuracy of microparts produced using two-photon polymerization depends on the accuracy of control of the positions of the focal spot. The accuracy becomes more important when these microparts need to be assembled into a whole with parts that are free to move in relation to each other. Ideally, the exact location of the movement of the focal spots in an optical system, no matter how complex it may be, can be solved using geometric optics. However, in reality, this is not so easy because of the complexity of optical systems and also due to the imperfections that lie between the design and the physical layout. We thus take a black-box approach such that the optical system is not examined but only the output result, and the command from the system is compared, interpreted and finally calibrated. The result is an extremely simple, yet very effective adaptation of the commanding of the focal spot that only requires the focal spot at the manufacturing plane to be monitored through a digital camera. We have also shown the effectiveness of the proposed method by fabricating a microstructure and measuring the fabrication error, which was found to be less than 3%.

  15. Electrodeposition of Low Stress Nickel Phosphorous Alloys for Precision Component Fabrication

    NASA Technical Reports Server (NTRS)

    Engelhaupt, Darell; Ramsey, Brian; Speegle, Chet; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Nickel alloys are favored for electroforming precision components. Nickel phosphorous and nickel cobalt phosphorous are studied in this work. A completely new and innovative electrolytic process eliminates the fumes present in electroless processes and is suitable for electroforming nickel phosphorous and nickel cobalt phosphorous alloys to any desirable thickness, using soluble anodes, without stripping of tanks. Solutions show excellent performance for extended throughput. Properties include, cleaner low temperature operation (40 - 45 C), high Faradaic efficiency, low stress, Rockwell C 52 - 54 hardness and as much as 2000 N per square millimeter tensile strength. Performance is compared to nickel and nickel cobalt electroforming.

  16. Design and fabrication of low-microwave loss coplannar waveguide and precise V groove on silicon substrate for optoelectronic packaging

    NASA Astrophysics Data System (ADS)

    Yang, Hua; Zhu, Hongliang; Xie, Hongyun; Zhao, Lingjuan; Zhou, Fan; Wang, Wei

    2005-11-01

    Optoelectronic packaging has become a most important factor that influences the final performance and cost of the module. In this paper, low microwave loss coplanar waveguide(CPW) on high resistivity silicon(HRS) and precise V groove in silicon substrate were successfully fabricated. The microwave attenuation of the CPW made on HRS with the simple process is lower than 2 dB/cm in the frequency range of 0~26GHz, and V groove has the accuracy in micro level and smooth surface.These two techniques built a good foundation for high frequency packaging and passive coupling of the optoelectronic devices. Based on these two techniques, a simple high resistivity silicon substrate that integrated V groove and CPW for flip-chip packaging of lasers was completed. It set a good example for more complicate optoelectronic packaging.

  17. A comparison of fabrication precision and mechanical reliability of 2 zirconia implant abutments.

    PubMed

    Kerstein, Robert B; Radke, John

    2008-01-01

    Studies have described the reliability of zirconia as an implant abutment material. The purpose of this in vitro study was to compare the precision and fracture strength of 2 different zirconia abutments angled at 30 degrees and loaded to failure in a standardized testing device. Twenty-nine Atlantis abutments in zirconia (AAZ) and 29 Nobel Biocare Procera AllZirkon abutments of comparable interface were measured for key interface feature statistical differences (analysis of variance; alpha = 95%). Each specimen was fixed to a regular-platform Brånemark System implant and mounted in an Instron machine. Increasing incremental loads were applied until failure. A 2-tailed t test for independent specimens and unequal variances was employed (alpha = 95%). The Weibull method determined the probability of failure of each abutment sample (alpha = 95%). Fractography by scanning electron microscopy determined the flaws at the fracture origins. Metrology inspection indicated that the AAZ showed no measurable dimensional differences of 4 key interface features. The mean failure load of the AAZ (831 N) was greater than the AllZirkon (740 N; P < .00006). The Weibull distribution showed that the AAZ would be more likely to survive intraoral occlusal loads (P < .0005). Both types of zirconia abutments demonstrated failure loads that exceed maximum human bite force. In vitro, the AAZ outperformed the AllZirkon in survivability. The clinical use of zirconia abutments is indicated when esthetics may be of concern.

  18. Layer-controlled precise fabrication of ultrathin MoS2 films by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Huang, Yazhou; Sha, Jingjie; Chen, Yunfei

    2017-05-01

    Monolayer and/or atomically thin transition metal dichalcogenides cover a wide range of two-dimensional (2D) materials, whose fascinating semiconducting and optical properties have made them promising candidate materials for optoelectronic devices. Controllable growth of these materials is critical for their device applications. By using MoCl5 and H2S as precursors, monolayer and ultrathin molybdenum disulfide (MoS2) films with controlled lamellar structure have been directly built layer by layer on SiO2 substrates without being followed by high-temperature annealing. Furthermore, the thickness of MoS2 films can be precisely regulated by applying different atomic layer deposition (ALD) cycles. Once an ALD cycle is applied, one molecular layer of MoS2 material will be ‘added’ on the substrate or original existing MoS2 films. At the initial stage (one to three ALD cycles), the density of MoS2 materials increases with an increase in ALD cycles, while a large area of continuous MoS2 film on the substrate can be obtained when four or more ALD cycles are applied. In this way, excellent triangular crystals of MoS2 with controlled atomic size in thickness and a highly oriented hexagonal crystal structures can be obtained by applying definite ALD cycles.

  19. Layer-controlled precise fabrication of ultrathin MoS2 films by atomic layer deposition.

    PubMed

    Liu, Lei; Huang, Yazhou; Sha, Jingjie; Chen, Yunfei

    2017-03-21

    Monolayer and/or atomically thin transition metal dichalcogenides cover a wide range of two-dimensional (2-D) materials, whose fascinating semiconducting and optical properties have made them being promising candidate materials for optoelectronic device. Controllable growth of these materials is critical for their device applications. By using MoCl5 and H2S as precursors, monolayer and ultrathin molybdenum disulfide (MoS2) films with controlled lamellar structure have been directly built layer by layer on SiO2 substrates without followed high-temperature annealing. Furthermore, the thickness of MoS2 films can be precisely regulated by applying different ALD cycles. Once an ALD cycle is applied, one molecular layer of MoS2 material will be "added" on substrate or original existing MoS2 films. At the initial stage (1 to 3 ALD cycles), the density of MoS2 materials increases with ALD cycle increasing, while large area of continuous MoS2 film on the substrate can be obtained when 4 or more ALD cycles are applied. By this way, excellent triangular crystal of MoS2 with controlled atomic size in thickness and highly oriented hexagonal crystal structure can be obtained by applying definite ALD cycles.

  20. Precision grinding for rapid fabrication of segments for extremely large telescopes using the Cranfield BoX

    NASA Astrophysics Data System (ADS)

    Tonnellier, Xavier; Morantz, Paul; Shore, Paul; Comley, Paul

    2010-07-01

    An ultra precision large optics grinding machine, BoX®, was developed and produced at Cranfield University. BoX® offers a rapid and economic solution for grinding large off-axis aspherical and free-form optical components. Grinding high accuracy surfaces with low subsurface damage reduces subsequent polishing time. This efficient grinding process provides the capacity to grind 1.5 m parts. This paper presents an analysis of Astrositall® optical ground parts: a hexagonal 84 m radius of curvature mirror of 1 m across corners and an off-axis 350 mm diameter mirror. The 1 m hexagonal part is representative of segments under study for making extremely large telescope (ELT) segmented mirrors. The second part was machined off-axis to demonstrate free-form fabrication capability. These operations demonstrate the scalability of the rapid grinding process developed for large free-form optics. The use of an error compensation procedure improved an initial ground form accuracy to +/- 1 μm p-v over 1 metre surface. The results highlighted the effect of grinding parameters and machine dynamics on form accuracy and fabrication time.

  1. Calibrating bimetallic grayscale photomasks to photoresist response for precise micro-optics fabrication

    NASA Astrophysics Data System (ADS)

    Chapman, Glenn H.; Qarehbaghi, Reza; Roche, Santiago

    2014-03-01

    Microfabricating high resolution micro-optics structures requires shape control to <1/8th wavelength (~60nm) in both vertical and horizontal surface precision. Grayscale bimetallic photomasks are bi-layer thermal resists consisting of two thin layers of Bi-on-Indium or Tin-on-Indium. A focused laser spot creates a thermal metal oxide with a controllably transparency set by the beam power of optical density from ~3OD (unexposed) to <0.22OD (fully exposed). A directwrite raster-scan photomask laser system with a CW Argon-ion laser at 514nm for the bimetallic writing and 457nm line for measuring the OD change used a feedback-controlled Gaussian beam to achieve 256-level grayscale masks. Setting the graylevels required to achieve uniform vertical steps in the photoresist requires adjustment in transparency based on the exact response curves of a given resist/development process. An initial model is developed using the classic resist threshold dose exposure D0 and dose to clear Dc creating a power law relation between the required exposure dose for each thickness step and the mask transparency. However real resists behave differently than the simple model near the threshold requiring careful calibrating of mask graylevel transparencies with the photoresist response curve for a given resist/development process. Test structures ranging from steps to ramps and complex patterns were examined via both SEM and profilometry from the resulting bimetallic grayscale masks. Secondary corrections modify the needed bimetallic OD due to the exposure source spectrum differences from the 457nm measurement. This enhances the patterning of micro-optic and 3D MEMS structures.

  2. Low-Resistivity Zinc Selenide for Heterojunctions

    NASA Technical Reports Server (NTRS)

    Stirn, R. J.

    1986-01-01

    Magnetron reactive sputtering enables doping of this semiconductor. Proposed method of reactive sputtering combined with doping shows potential for yielding low-resistivity zinc selenide films. Zinc selenide attractive material for forming heterojunctions with other semiconductor compounds as zinc phosphide, cadmium telluride, and gallium arsenide. Semiconductor junctions promising for future optoelectronic devices, including solar cells and electroluminescent displays. Resistivities of zinc selenide layers deposited by evaporation or chemical vapor deposition too high to form practical heterojunctions.

  3. Low-Resistivity Zinc Selenide for Heterojunctions

    NASA Technical Reports Server (NTRS)

    Stirn, R. J.

    1986-01-01

    Magnetron reactive sputtering enables doping of this semiconductor. Proposed method of reactive sputtering combined with doping shows potential for yielding low-resistivity zinc selenide films. Zinc selenide attractive material for forming heterojunctions with other semiconductor compounds as zinc phosphide, cadmium telluride, and gallium arsenide. Semiconductor junctions promising for future optoelectronic devices, including solar cells and electroluminescent displays. Resistivities of zinc selenide layers deposited by evaporation or chemical vapor deposition too high to form practical heterojunctions.

  4. Microfluidic assisted one-step fabrication of porous silicon@acetalated dextran nanocomposites for precisely controlled combination chemotherapy.

    PubMed

    Liu, Dongfei; Zhang, Hongbo; Mäkilä, Ermei; Fan, Jin; Herranz-Blanco, Bárbara; Wang, Chang-Fang; Rosa, Ricardo; Ribeiro, António J; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

    2015-01-01

    An advanced nanocomposite consisting of an encapsulated porous silicon (PSi) nanoparticle and an acid-degradable acetalated dextran (AcDX) matrix (nano-in-nano), was efficiently fabricated by a one-step microfluidic self-assembly approach. The obtained nano-in-nano PSi@AcDX composites showed improved surface smoothness, homogeneous size distribution, and considerably enhanced cytocompatibility. Furthermore, multiple drugs with different physicochemical properties have been simultaneously loaded into the nanocomposites with a ratiometric control. The release kinetics of all the payloads was predominantly controlled by the decomposition rate of the outer AcDX matrix. To facilitate the intracellular drug delivery, a nona-arginine cell-penetrating peptide (CPP) was chemically conjugated onto the surface of the nanocomposites by oxime click chemistry. Taking advantage of the significantly improved cell uptake, the proliferation of two breast cancer cell lines was markedly inhibited by the CPP-functionalized multidrug-loaded nanocomposites. Overall, this nano-in-nano PSi@polymer composite prepared by the microfluidic self-assembly approach is a universal platform for nanoparticles encapsulation and precisely controlled combination chemotherapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Performance of low resistance microchannel plate stacks

    NASA Technical Reports Server (NTRS)

    Siegmund, O. H. W.; Stock, J.

    1991-01-01

    Results are presented from an evaluation of three sets of low resistance microchannel plate (MCP) stacks; the tests encompassed gain, pulse-height distribution, background rate, event rate capacity as a function of illuminated area, and performance changes due to high temperature bakeout and high flux UV scrub. The MCPs are found to heat up, requiring from minutes to hours to reach stabilization. The event rate is strongly dependent on the size of the area being illuminated, with larger areas experiencing a gain drop onset at lower rates than smaller areas.

  6. Performance of low resistance microchannel plate stacks

    NASA Technical Reports Server (NTRS)

    Siegmund, O. H. W.; Stock, J.

    1991-01-01

    Results are presented from an evaluation of three sets of low resistance microchannel plate (MCP) stacks; the tests encompassed gain, pulse-height distribution, background rate, event rate capacity as a function of illuminated area, and performance changes due to high temperature bakeout and high flux UV scrub. The MCPs are found to heat up, requiring from minutes to hours to reach stabilization. The event rate is strongly dependent on the size of the area being illuminated, with larger areas experiencing a gain drop onset at lower rates than smaller areas.

  7. Fabrication

    NASA Astrophysics Data System (ADS)

    Angel, Roger; Helms, Richard; Bilbro, Jim; Brown, Norman; Eng, Sverre; Hinman, Steve; Hull-Allen, Greg; Jacobs, Stephen; Keim, Robert; Ulmer, Melville

    1992-08-01

    What aspects of optical fabrication technology need to be developed so as to facilitate existing planned missions, or enable new ones? Throughout the submillimeter to UV wavelengths, the common goal is to push technology to the limits to make the largest possible apertures that are diffraction limited. At any one wavelength, the accuracy of the surface must be better than lambda/30 (rms error). The wavelength range is huge, covering four orders of magnitude from 1 mm to 100 nm. At the longer wavelengths, diffraction limited surfaces can be shaped with relatively crude techniques. The challenge in their fabrication is to make as large as possible a reflector, given the weight and volume constraints of the launch vehicle. The limited cargo diameter of the shuttle has led in the past to emphasis on deployable or erectable concepts such as the Large Deployable Reflector (LDR), which was studied by NASA for a submillimeter astrophysics mission. Replication techniques that can be used to produce light, low-cost reflecting panels are of great interest for this class of mission. At shorter wavelengths, in the optical and ultraviolet, optical fabrication will tax to the limit the most refined polishing methods. Methods of mechanical and thermal stabilization of the substrate will be severely stressed. In the thermal infrared, the need for large aperture is tempered by the even stronger need to control the telescope's thermal emission by cooled or cryogenic operation. Thus, the SIRTF mirror at 1 meter is not large and does not require unusually high accuracy, but the fabrication process must produce a mirror that is the right shape at a temperature of 4 K. Future large cooled mirrors will present more severe problems, especially if they must also be accurate enough to work at optical wavelengths. At the very shortest wavelengths accessible to reflecting optics, in the x-ray domain, the very low count fluxes of high energy photons place a premium on the collecting area. It is

  8. Fabrication

    NASA Technical Reports Server (NTRS)

    Angel, Roger; Helms, Richard; Bilbro, Jim; Brown, Norman; Eng, Sverre; Hinman, Steve; Hull-Allen, Greg; Jacobs, Stephen; Keim, Robert; Ulmer, Melville

    1992-01-01

    What aspects of optical fabrication technology need to be developed so as to facilitate existing planned missions, or enable new ones? Throughout the submillimeter to UV wavelengths, the common goal is to push technology to the limits to make the largest possible apertures that are diffraction limited. At any one wavelength, the accuracy of the surface must be better than lambda/30 (rms error). The wavelength range is huge, covering four orders of magnitude from 1 mm to 100 nm. At the longer wavelengths, diffraction limited surfaces can be shaped with relatively crude techniques. The challenge in their fabrication is to make as large as possible a reflector, given the weight and volume constraints of the launch vehicle. The limited cargo diameter of the shuttle has led in the past to emphasis on deployable or erectable concepts such as the Large Deployable Reflector (LDR), which was studied by NASA for a submillimeter astrophysics mission. Replication techniques that can be used to produce light, low-cost reflecting panels are of great interest for this class of mission. At shorter wavelengths, in the optical and ultraviolet, optical fabrication will tax to the limit the most refined polishing methods. Methods of mechanical and thermal stabilization of the substrate will be severely stressed. In the thermal infrared, the need for large aperture is tempered by the even stronger need to control the telescope's thermal emission by cooled or cryogenic operation. Thus, the SIRTF mirror at 1 meter is not large and does not require unusually high accuracy, but the fabrication process must produce a mirror that is the right shape at a temperature of 4 K. Future large cooled mirrors will present more severe problems, especially if they must also be accurate enough to work at optical wavelengths. At the very shortest wavelengths accessible to reflecting optics, in the x-ray domain, the very low count fluxes of high energy photons place a premium on the collecting area. It is

  9. Fabrication of a high-precision spherical micromirror by bending a silicon plate with a metal pad.

    PubMed

    Wu, Tong; Hane, Kazuhiro

    2011-09-20

    We demonstrate here the fabrication of a smooth mirror surface by bending a thin silicon plate. A spherical surface is achieved by the bending moment generated in the circumference of the micromirror. Both convex and concave spherical micromirrors are realized through the anodic bonding of silicon and Pyrex glass. Since the mirror surface is originated from the polished silicon surface and no additional etching is introduced for manufacturing, the surface roughness is thus limited to the polishing error. This novel approach opens possibilities for fabricating a smooth surface for micromirror and microlens applications.

  10. Simulation of surface topography of big aspheric fabrication by ultra-precision diamond turning based on tool swing feeding

    NASA Astrophysics Data System (ADS)

    Yao, Honghui; Li, Zengqiang; Sun, Tao

    2014-08-01

    In the respect of ultra-precision manufacturing of axisymmetric surface, the machine tool with tool swing feeding which has less interpolation error sources compared to the conventional ultra-precision diamond turning machine tool with T-structureis worth studying.Therefore,based on the dynamic simulation modeling and multi-body dynamics theory,in this paper, we establish the control model,and tool path for Ultra-precision machine.Then we got the model for surface topography with differentinput parameters like spindle speed, feedrate, tool parameters and so on. Taking the spherical optics part with diameter of 300 mm, for example, we input the process parameters and get its surface topography, then evaluate its surface quality by surface roughness value (Ra) and surface shape accuracy(PV) .

  11. A high-brightness light guide plate with high precise double-sided microstructures fabricated using the fixed boundary hot embossing technique

    NASA Astrophysics Data System (ADS)

    Yang, Cheng-Huan; Yang, Sen-Yeu

    2013-03-01

    In recent years, microstructures have been widely applied in many key optical elements and bio-elements. The effective and efficient fabrication of optical elements and bio-elements with superior performance has become an essential challenge. This requires very accurate shape replication of microstructures. The plate-to-plate hot embossing process is the most likely method of mass production for the replication of double-sided micro/nano structures with high precision and quality. However, the traditional uniform heating hot embossing process as the free boundary of open die forging leads to variation. In this research, three techniques are implemented; the conventional uniform heating technique, the non-uniform pressure compensating technique and the fixed boundary hot embossing technique. The temperature distribution of the hot-plates of the fixed boundary hot embossing technique are designed to keep the temperature in the center part higher than the outer part on the surface of the substrates. This phenomenon changes free boundary in conventional uniform heating into fixed boundary. The results demonstrate the potential of the fixed boundary hot embossing technique for the fabrication of large-area high brightness LGPs with double-sided microstructures. The results are also helpful for enhancing the performance of optical elements and bio-elements fabricated using the fixed boundary hot embossing technique.

  12. Mechanical properties and cell-culture characteristics of a polycaprolactone kagome-structure scaffold fabricated by a precision extruding deposition system.

    PubMed

    Lee, Se-Hwan; Cho, Yong Sang; Hong, Myoung Wha; Lee, Bu-Kyu; Park, Yongdoo; Park, Sang-Hyug; Kim, Young Yul; Cho, Young-Sam

    2017-09-13

    To enhance the mechanical properties of three-dimensional (3D) scaffolds used for bone regeneration in tissue engineering, many researchers have studied their structure and chemistry. In the structural engineering field, the kagome structure has been known to have an excellent relative strength. In this study, to enhance the mechanical properties of a synthetic polymer scaffold used for tissue engineering, we applied the 3D kagome structure to a porous scaffold for bone regeneration. Prior to fabricating the biocompatible-polymer scaffold, the ideal kagome structure, which was manufactured by a 3D printer of the digital light processing type, was compared with a grid-structure, which was used as the control group, using a compressive experiment. A polycaprolactone (PCL) kagome-structure scaffold was successfully fabricated by additive manufacturing using a 3D printer with a precision extruding deposition head. To assess the physical characteristics of the fabricated PCL-kagome-structure scaffold, we analyzed its porosity, pore size, morphological structure, surface roughness, compressive stiffness, and mechanical bending properties. The results showed that, the mechanical properties of proposed kagome-structure scaffold were superior to those of a grid-structure scaffold. Moreover, Sarcoma osteogenic (Saos-2) cells were used to evaluate the characteristics of in vitro cell proliferation. We carried out cell counting kit-8 (CCK-8) and DNA contents assays. Consequently, the cell proliferation of the kagome-structure scaffold was increased; this could be because the surface roughness of the kagome-structure scaffold enhances initial cell attachment.

  13. Fabrication process for CMUT arrays with polysilicon electrodes, nanometre precision cavity gaps and through-silicon vias

    NASA Astrophysics Data System (ADS)

    Due-Hansen, J.; Midtbø, K.; Poppe, E.; Summanwar, A.; Jensen, G. U.; Breivik, L.; Wang, D. T.; Schjølberg-Henriksen, K.

    2012-07-01

    Capacitive micromachined ultrasound transducers (CMUTs) can be used to realize miniature ultrasound probes. Through-silicon vias (TSVs) allow for close integration of the CMUT and read-out electronics. A fabrication process enabling the realization of a CMUT array with TSVs is being developed. The integrated process requires the formation of highly doped polysilicon electrodes with low surface roughness. A process for polysilicon film deposition, doping, CMP, RIE and thermal annealing that resulted in a film with sheet resistance of 4.0 Ω/□ and a surface roughness of 1 nm rms has been developed. The surface roughness of the polysilicon film was found to increase with higher phosphorus concentrations. The surface roughness also increased when oxygen was present in the thermal annealing ambient. The RIE process for etching CMUT cavities in the doped polysilicon gave a mean etch depth of 59.2 ± 3.9 nm and a uniformity across the wafer ranging from 1.0 to 4.7%. The two presented processes are key processes that enable the fabrication of CMUT arrays suitable for applications in for instance intravascular cardiology and gastrointestinal imaging.

  14. Overlay of semi-dried functional layers in offset printing for rapid and high-precision fabrication of flexible TFTs

    NASA Astrophysics Data System (ADS)

    Kusaka, Yasuyuki; Sugihara, Kazuyoshi; Koutake, Masayoshi; Ushijima, Hirobumi

    2014-03-01

    We achieved a reduction in the misregistration of overlying patterns printed on a flexible plastic film and a drastically shorter processing time with fully printed thin-film transistor (TFT) fabrication. This was achieved using a newly developed wet-on-wet (WoW) printing process wherein a subsequent layer can be printed on a previous semi-dried (not-sintered) layer. In the WoW process, as examined by rheological measurements, a semi-dried (highly solidified) state of ink was attained before transferring by utilizing the solvent uptake of a PDMS blanket in offset printing to ensure the structural integrity of the ink layer, and to reduce the inter-contamination of adjoining layers. Loss-on-drying tests and resistivity measurements indicated that molecular penetration at the boundary of adjoining layers with a length of c.a. 70 nm occurred in the WoW process; however, with thicker electrodes, we successfully fabricated a WoW-processed TFT whose performance was comparable with a TFT formed by a conventional printing process.

  15. Precisions on the structure of the Basque Arc (western Pyrenees, Spain): preliminary results from magnetic fabrics from the Biscay Synclinorium

    NASA Astrophysics Data System (ADS)

    Vegas, Néstor; Aranguren, Aitor; Rodríguez-Méndez, Lidia; Cuevas, Julia; María Tubía, José; Julián Esteban, José

    2017-04-01

    The Mesozoic Basque-Cantabrian basin (western Pyrenees) was inverted during the Alpine Orogeny in late Cretaceous-Eocene times. The central sector of the basin, the Basque Arc is characterized by the existence of large folds (80 km long) that outline an arc. This study focuses on the interpretation of AMS fabrics in rocks from the Biscay Synclinorium, a major fold system of the Basque Arc that verges to the NE, with sub-horizontal, N110˚ E trending axes and axial planes striking to N110˚ E and dipping steeply to the SW (Calvo-Rathert et al., 2007). The aim of this contribution is characterize the deformation around the Biscay Synclinorium. For this reason we combined fieldwork with magnetic fabric analysis of 95 cores in Upper Cretaceous sedimentary rocks of the Biscay Synclinorium. 68 cores come from the Calcareous formation (marls, sandy limestones and limestones of Cenomanian to Campanian age) that makes part of the northeastern limb of the synclinorium and the remaining 27 cores from the Detrital-calcareous flysch (a multilayer sequence with sandy limestones and marls of Maastrichtian age) that crops out in the synclinorium core (Garrote et al., 1991). In the Upper Cretaceous Calcareous formation there is a penetrative cleavage that mainly strikes to N110˚ E dipping 50˚ to 60˚ to the SW (S1). In the Detrital-calcareous flysch of the core, the best-preserved planar structure is the bedding and only locally an axial planar cleavage is observed. Intersection lineations are sub-horizontal and N110˚ E-trending. The measurements of the magnetic susceptibility provide low k values ranging between 99x10-6 and 403x10-6 SI. The anisotropy of the magnetic susceptibility, P, reaches values of 1.213, pointing to the overprinting of tectonic deformation on primary magnetic fabrics of sedimentary origin. The magnetic foliation shows a fairly uniform arrangement that is nearly coincident with the dominant planar structures of the rocks, S0 or S1in the core and the limb

  16. Accuracy and precision of polyurethane dental arch models fabricated using a three-dimensional subtractive rapid prototyping method with an intraoral scanning technique.

    PubMed

    Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Kim, Ji-Hwan; Kim, Hae-Young

    2014-03-01

    This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of inter-examiner and inter-method variability. The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models.

  17. Precise Morphology Control and Continuous Fabrication of Perovskite Solar Cells Using Droplet-Controllable Electrospray Coating System.

    PubMed

    Hong, Seung Chan; Lee, Gunhee; Ha, Kyungyeon; Yoon, Jungjin; Ahn, Namyoung; Cho, Woohyung; Park, Mincheol; Choi, Mansoo

    2017-03-08

    Herein, we developed a novel electrospray coating system for continuous fabrication of perovskite solar cells with high performance. Our system can systemically control the size of CH3NH3PbI3 precursor droplets by modulating the applied electrical potential, shown to be a crucial factor for the formation of perovskite films. As a result, we have obtained pinhole-free and large grain-sized perovskite solar cells, yielding the best PCE of 13.27% with little photocurrent hysteresis. Furthermore, the average PCE through the continuous coating process was 11.56 ± 0.52%. Our system demonstrates not only the high reproducibility but also a new way to commercialize high-quality perovskite solar cells.

  18. CAD/CAM-Assisted Auricular Prosthesis Fabrication for a Quick, Precise, and More Retentive Outcome: A Clinical Report.

    PubMed

    Yadav, Sushma; Narayan, Aparna Ichangod; Choudhry, Archit; Balakrishnan, Dhanasekar

    2017-01-24

    Auricular defects comprise a large proportion of maxillofacial deformities. Most patients with acquired deformities have psychosocial ineptness and seek cosmetic rehabilitation. Although minor defects can be corrected surgically, extensive deformities are difficult to reconstruct with plastic surgery. Contrary to that, prosthetic restoration can provide excellent esthetic results. The conventional methods of maxillofacial prosthesis fabrication are time consuming and the outcome depends on the technician's skill. The advent of CAD/CAM technology in the field of dentistry has brought enormous improvement in the quality of health care provided. In the past decade, several methods have been described employing CAD/CAM techniques for the cosmetic rehabilitation of auricular defects. This clinical report details the integration of multiple digital technologies of CT scanning, computer aided design, and rapid prototyping to construct an ear prosthesis with limited number of appointments.

  19. Precise control of two-dimensional composition of proteins and nanoparticle conjugate for functional nanostructured material fabrication.

    PubMed

    Uto, Koichiro; Yamamoto, Kazuya; Kishimoto, Naoko; Muraoka, Masahiro; Aoyagi, Takao; Yamashita, Ichiro

    2012-07-15

    In this study, we quantitatively analyzed the electrostatic blend adsorption of ferritin and apoferritin onto the surface of the precursor films by using a quartz crystal microbalance (QCM), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The precursor films were successively prepared by the alternate adsorption of poly(diallyldimethylammonium chloride) (PDDA) and poly(sodium 4-styrenesulfonate) (PSS) in the presence of 150 mM NaCl concentration onto the QCM substrate. We observed a monolayer adsorption of both ferritin and apoferritin by means of electrostatic interaction onto the outermost PDDA surface at pH 10.0. Under this condition, the composition of ferritin and apoferritin within the monolayer is linearly dependent on their ratios in the blended solution, thus showed an ideal blend adsorption behavior. The perfectly identical structure of ferritin and apoferritin should be contributed to this ideal blend adsorption behavior. We also studied the effects of total concentrations of their solution on ferritin and apoferritin blend adsorption. This study on the blend adsorption of ferritin and apoferritin by electrostatic interaction will be applied to the fabrication of multi-components homogeneous NP array because apoferritin can accommodate a variety of nanometer size inorganic materials within their interior spaces.

  20. Precise femtosecond laser crater fabrication in hard nanolayered AlTiN/TiN coating on steel substrate

    NASA Astrophysics Data System (ADS)

    Gaković, B.; Petrović, S.; Albu, C.; Zamfirescu, M.; Panjan, P.; Milovanović, D.; Popescu-Pelin, G.; Mihailescu, I. N.

    2017-03-01

    Processing of AlTiN/TiN multilayered hard coatings by femtosecond (fs) laser pulses has been investigated. Irradiation was performed in air with linearly polarized laser radiation with pulses of 200 fs duration at 775 nm wavelength. Single or 1000 subsequent laser pulses were directed at normal incidence towards target surface. Laser energy per pulse was adjusted from 0.5 to 50 μJ and corresponding fluence was 0.17-17.5 J cm-2. The as deposited and laser-ablated samples were characterized by optical confocal microscopy, optical profilometry and scanning and transmition electron microscopy. In case of the AlTiN/TiN coating, a single-pulse damage threshold of 0.41 J cm-2 was estimated. Well defined holes/craters with diameters from 7 to 35 μm, up to 40 μm depth were drilled, depending on laser pulse energy and number, after 1000 laser pulses. For small energy/fluence, laser induced periodical surface structures were observed. A model is discussed which can account for these features by the accumulation effect during multi-pulse irradiation. The forming craters can prove useful for fabrication of micron solid state lubricant reservoirs in the protective coating-steel system.

  1. High precision and high yield fabrication of dense nanoparticle arrays onto DNA origami at statistically independent binding sites

    NASA Astrophysics Data System (ADS)

    Takabayashi, Sadao; Klein, William P.; Onodera, Craig; Rapp, Blake; Flores-Estrada, Juan; Lindau, Elias; Snowball, Lejmarc; Sam, Joseph T.; Padilla, Jennifer E.; Lee, Jeunghoon; Knowlton, William B.; Graugnard, Elton; Yurke, Bernard; Kuang, Wan; Hughes, William L.

    2014-10-01

    High precision, high yield, and high density self-assembly of nanoparticles into arrays is essential for nanophotonics. Spatial deviations as small as a few nanometers can alter the properties of near-field coupled optical nanostructures. Several studies have reported assemblies of few nanoparticle structures with controlled spacing using DNA nanostructures with variable yield. Here, we report multi-tether design strategies and attachment yields for homo- and hetero-nanoparticle arrays templated by DNA origami nanotubes. Nanoparticle attachment yield via DNA hybridization is comparable with streptavidin-biotin binding. Independent of the number of binding sites, >97% site-occupation was achieved with four tethers and 99.2% site-occupation is theoretically possible with five tethers. The interparticle distance was within 2 nm of all design specifications and the nanoparticle spatial deviations decreased with interparticle spacing. Modified geometric, binomial, and trinomial distributions indicate that site-bridging, steric hindrance, and electrostatic repulsion were not dominant barriers to self-assembly and both tethers and binding sites were statistically independent at high particle densities.High precision, high yield, and high density self-assembly of nanoparticles into arrays is essential for nanophotonics. Spatial deviations as small as a few nanometers can alter the properties of near-field coupled optical nanostructures. Several studies have reported assemblies of few nanoparticle structures with controlled spacing using DNA nanostructures with variable yield. Here, we report multi-tether design strategies and attachment yields for homo- and hetero-nanoparticle arrays templated by DNA origami nanotubes. Nanoparticle attachment yield via DNA hybridization is comparable with streptavidin-biotin binding. Independent of the number of binding sites, >97% site-occupation was achieved with four tethers and 99.2% site-occupation is theoretically possible with five

  2. Precisely-controlled fabrication of single ZnO nanoemitter arrays and their possible application in low energy parallel electron beam exposure.

    PubMed

    He, H; She, J C; Huang, Y F; Deng, S Z; Xu, N S

    2012-03-21

    Precisely-controlled fabrication of single ZnO nanoemitter arrays and their possible application in low energy parallel electron beam exposure are reported. A well defined polymethyl methacrylate (PMMA) nanohole template was employed for local solution-phase growth of single ZnO nanoemitter arrays. Chlorine plasma etching for surface smoothing and pulsed-laser illumination in nitrogen for nitrogen doping were performed, which can significantly enhance the electron emission and improve the emitter-to-emitter uniformity in performance. Mechanisms responsible for the field emission enhancing effect are proposed. Low voltage (368 V) e-beam exposure was performed by using a ZnO nanoemitter array and a periodical hole pattern (0.72-1.26 μm in diameter) was produced on a thin (25 nm) PMMA. The work demonstrates the feasibility of utilizing single ZnO nano-field emitter arrays for low voltage parallel electron beam lithography.

  3. High Precision and High Yield Fabrication of Dense Nanoparticle Arrays onto DNA Origami at Statistically Independent Binding Sites †

    PubMed Central

    Takabayashi, Sadao; Klein, William P.; Onodera, Craig; Rapp, Blake; Flores-Estrada, Juan; Lindau, Elias; Snowball, Lejmarc; Sam, Joseph Tyler; Padilla, Jennifer E.; Lee, Jeunghoon; Knowlton, William B.; Graugnard, Elton; Yurke, Bernard; Kuang, Wan; Hughes, William L.

    2015-01-01

    High precision, high yield, and high density self-assembly of nanoparticles into arrays is essential for nanophotonics. Spatial deviations as small as a few nanometers can alter the properties of near-field coupled optical nanostructures. Several studies have reported assemblies of few nanoparticle structures with controlled spacing using DNA nanostructures with variable yield. Here, we report multi-tether design strategies and attachment yields for homo- and hetero-nanoparticle arrays templated by DNA origami nanotubes. Nanoparticle attachment yield via DNA hybridization is comparable with streptavidin-biotin binding. Independent of the number of binding sites, >97% site-occupation was achieved with four tethers and 99.2% site-occupation is theoretically possible with five tethers. The interparticle distance was within 2 nm of all design specifications and the nanoparticle spatial deviations decreased with interparticle spacing. Modified geometric, binomial, and trinomial distributions indicate that site-bridging, steric hindrance, and electrostatic repulsion were not dominant barriers to self-assembly and both tethers and binding sites were statistically independent at high particle densities. PMID:25311051

  4. Precisely controlled resorcinol-formaldehyde resin coating for fabricating core-shell, hollow, and yolk-shell carbon nanostructures

    NASA Astrophysics Data System (ADS)

    Fang, Xiaoliang; Liu, Shengjie; Zang, Jun; Xu, Chaofa; Zheng, Ming-Sen; Dong, Quan-Feng; Sun, Daohua; Zheng, Nanfeng

    2013-07-01

    This work provides a facile one-step sol-gel route to synthesize high-quality resorcinol-formaldehyde (RF) resin coated nanocomposites that can be further used to fabricate desired carbon nanostructures. Colloidal particles with different morphologies and sizes can be coated with high-quality RF resin shells by the proposed cationic surfactant assisted RF resin coating strategy. The as-synthesized RF resin coated nanocomposites are ideal candidates for selective synthesis of core-shell, hollow, and yolk-shell carbon nanostructures. Based on the carboxylic functional RF resin coating, graphitic carbon nanostructures can also be synthesized by employing the graphitization catalyst. The as-synthesized carbon nanostructures show the advantageous performances in several applications. Hollow carbon spheres are potential electrode materials for lithium-sulfur batteries. Hollow graphitic spheres are promising catalyst supports for oxygen reduction reaction. And yolk-shell structured Au@HCS nanoreactors with ultrathin shells exhibit high catalytic activity and recyclability in confined catalysis.This work provides a facile one-step sol-gel route to synthesize high-quality resorcinol-formaldehyde (RF) resin coated nanocomposites that can be further used to fabricate desired carbon nanostructures. Colloidal particles with different morphologies and sizes can be coated with high-quality RF resin shells by the proposed cationic surfactant assisted RF resin coating strategy. The as-synthesized RF resin coated nanocomposites are ideal candidates for selective synthesis of core-shell, hollow, and yolk-shell carbon nanostructures. Based on the carboxylic functional RF resin coating, graphitic carbon nanostructures can also be synthesized by employing the graphitization catalyst. The as-synthesized carbon nanostructures show the advantageous performances in several applications. Hollow carbon spheres are potential electrode materials for lithium-sulfur batteries. Hollow graphitic

  5. Investigating extremely low resistance ohmic contacts to silicon carbide using a novel test structure

    NASA Astrophysics Data System (ADS)

    Pan, Yue; Collins, Aaron M.; Algahtani, Fahid; Leech, Patrick W.; Reeves, Geoffrey K.; Tanner, Philip; Holland, Anthony S.

    2013-12-01

    Low resistance contracts to highly doped silicon carbide (SiC) are investigated. Using a novel test structure that is easy to fabricate and easy to use, this paper demonstrates how it is used to reliably determine relatively low specific contact resistivities which vary with heat treatment. The test structure requires no error correction and is not affected by parasitic resistances. Using the test structure, small changes in specific contact resistivity are determined for small temperature changes. Results will be presented and discussed on the application of this novel test structure for nickel to highly doped SiC.

  6. Injection photodiodes based on low-resistivity ZnS single crystals

    SciTech Connect

    Losev, V. V.

    2009-12-15

    Results of an experimental study of Ni-n-n{sup +}-In photodiode structures fabricated from a low-resistivity ZnS:Al crystal (n{sup +}-region) are reported. The high-resistivity compensated n-type layer is produced by thermal diffusion of silver. The photodiodes exhibit an injection amplification of the photocurrent under a forward bias of 1-10 V. The dependence of the currents through the diodes on the thickness of the n-type layer in the dark and under UV irradiation is determined. The photosensitivity is at a maximum in the fundamental absorption range in a narrow spectral band.

  7. Theoretical and experimental research on error analysis and optimization of tool path in fabricating aspheric compound eyes by precision micro milling

    NASA Astrophysics Data System (ADS)

    Chen, Mingjun; Xiao, Yong; Tian, Wenlan; Wu, Chunya; Chu, Xin

    2014-05-01

    Structure design and fabricating methods of three-dimensional (3D) artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial compound eyes. However, spherical optical compound eyes are less at optical performance than the eyes of insects, and it is difficult to further improve the imaging quality of compound eyes by means of micro-nano optical manufacturing. In this research, nonhomogeneous aspheric compound eyes (ACEs) are designed and fabricated. The nonhomogeneous aspheric structure is applied to calibrate the spherical aberration. Micro milling with advantages in processing three-dimensional micro structures is adopted to manufacture ACEs. In order to obtain ACEs with high imaging quality, the tool paths are optimized by analyzing the influence factors consisting of interpolation allowable error, scallop height and tool path pattern. In the experiments, two kinds of ACEs are manufactured by micro-milling with different too path patterns and cutting parameter on the miniature precision five-axis milling machine tool. The experimental results indicate that the ACEs of high surface quality can be achieved by circularly milling small micro-lens individually with changeable cutting depth. A prototype of the aspheric compound eye (ACE) with surface roughness ( R a) below 0.12 μm is obtained with good imaging performance. This research ameliorates the imaging quality of 3D artificial compound eyes, and the proposed method of micro-milling can improve surface processing quality of compound eyes.

  8. Advanced Fabrication Techniques for Precisely Controlled Micro and Nano Scale Environments for Complex Tissue Regeneration and Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Holmes, Benjamin

    As modern medicine advances, it is still very challenging to cure joint defects due to their poor inherent regenerative capacity, complex stratified architecture, and disparate biomechanical properties. The current clinical standard for catastrophic or late stage joint degradation is a total joint implant, where the damaged joint is completely excised and replaced with a metallic or artificial joint. However, these procedures still only lasts for 10-15 years, and there are hosts of recovery complications which can occur. Thus, these studies have sought to employ advanced biomaterials and scaffold fabricated techniques to effectively regrow joint tissue, instead of merely replacing it with artificial materials. We can hypothesize here that the inclusion of biomimetic and bioactive nanomaterials with highly functional electrospun and 3D printed scaffold can improve physical characteristics (mechanical strength, surface interactions and nanotexture) enhance cellular growth and direct stem cell differentiation for bone, cartilage and vascular growth as well as cancer metastasis modeling. Nanomaterial inclusion and controlled 3D printed features effectively increased nano surface roughness, Young's Modulus and provided effective flow paths for simulated arterial blood. All of the approaches explored proved highly effective for increasing cell growth, as a result of increasing micro-complexity and nanomaterial incorporation. Additionally, chondrogenic and osteogenic differentiation, cell migration, cell to cell interaction and vascular formation were enhanced. Finally, growth-factor(gf)-loaded polymer nanospheres greatly improved vascular cell behavior, and provided a highly bioactive scaffold for mesenchymal stem cell (MSC) and human umbilical vein endothelial cell (HUVEC) co-culture and bone formation. In conclusion, electrospinning and 3D printing when combined effectively with biomimetic and bioactive nanomaterials (i.e. carbon nanomaterials, collagen, nHA, polymer

  9. Accuracy and precision of polyurethane dental arch models fabricated using a three-dimensional subtractive rapid prototyping method with an intraoral scanning technique

    PubMed Central

    Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Kim, Ji-Hwan

    2014-01-01

    Objective This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Methods Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of inter-examiner and inter-method variability. Results The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. Conclusions The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models. PMID:24696823

  10. Successful fabrication of a convex platform PMMA cell-counting slide using a high-precision perpendicular dual-spindle CNC machine tool

    NASA Astrophysics Data System (ADS)

    Chen, Shun-Tong; Chang, Chih-Hsien

    2013-12-01

    This study presents a novel approach to the fabrication of a biomedical-mold for producing convex platform PMMA (poly-methyl-meth-acrylate) slides for counting cells. These slides allow for the microscopic examination of urine sediment cells. Manufacturing of such slides incorporates three important procedures: (1) the development of a tabletop high-precision dual-spindle CNC (computerized numerical control) machine tool; (2) the formation of a boron-doped polycrystalline composite diamond (BD-PCD) wheel-tool on the machine tool developed in procedure (1); and (3) the cutting of a multi-groove-biomedical-mold array using the formed diamond wheel-tool in situ on the developed machine. The machine incorporates a hybrid working platform providing wheel-tool thinning using spark erosion to cut, polish, and deburr microgrooves on NAK80 steel directly. With consideration given for the electrical conductive properties of BD-PCD, the diamond wheel-tool is thinned to a thickness of 5 µm by rotary wire electrical discharge machining. The thinned wheel-tool can grind microgrooves 10 µm wide. An embedded design, which inserts a close fitting precision core into the biomedical-mold to create step-difference (concave inward) of 50 µm in height between the core and the mold, is also proposed and realized. The perpendicular dual-spindles and precision rotary stage are features that allow for biomedical-mold machining without the necessity of uploading and repositioning materials until all tasks are completed. A PMMA biomedical-slide with a plurality of juxtaposed counting chambers is formed and its usefulness verified.

  11. Electrical and microstructure analysis of nickel-based low-resistance ohmic contacts to n-GaSb

    SciTech Connect

    Rahimi, Nassim Aragon, Andrew A.; Romero, Orlando S.; Shima, Darryl M.; Rotter, Thomas J.; Mukherjee, Sayan D.; Balakrishnan, Ganesh; Lester, Luke F.

    2013-12-01

    Ultra low resistance ohmic contacts are fabricated on n-GaSb grown by molecular beam epitaxy. Different doping concentrations and n-GaSb thicknesses are studied to understand the tunneling transport mechanism between the metal contacts and the semiconductor. Different contact metallization and anneal process windows are investigated to achieve optimal penetration depth of Au in GaSb for low resistances. The fabrication, electrical characterization, and microstructure analysis of the metal-semiconductor interfaces created during ohmic contact formation are discussed. The characterization techniques include cross-sectional transmission electron microscopy and energy dispersive spectroscopy. Specific transfer resistances down to 0.1 Ω mm and specific contact resistances of 1 × 10{sup −6} Ω cm{sup 2} are observed.

  12. Superconducting cable-in-conduit low resistance splice

    DOEpatents

    Artman, Thomas A.

    2003-06-24

    A low resistance splice connects two cable-in-conduit superconductors to each other. Dividing collars for arranging sub-cable units from each conduit are provided, along with clamping collars for mating each sub-cable wire assembly to form mated assemblies. The mated assemblies ideally can be accomplished by way of splicing collar. The mated assemblies are cooled by way of a flow of coolant, preferably helium. A method for implementing such a splicing is also described.

  13. Asymmetric spin absorption across a low-resistance oxide barrier

    SciTech Connect

    Chen, Shuhan; Qin, Chuan; Ji, Yi

    2015-07-21

    An unconventional method of nonlocal spin detection is demonstrated in mesoscopic lateral spin valves at room temperature. Clear nonlocal spin signals are detected between the two ends of an extended ferromagnetic spin detector. This is different from the conventional method in which the nonlocal voltage is measured between the spin detector and the nonmagnetic channel. The results can be understood as spatially non-uniform absorption of a pure spin current into the spin detector across a low-resistance oxide interface.

  14. Low resistivity contact to iron-pnictide superconductors

    DOEpatents

    Tanatar, Makariy; Prozorov, Ruslan; Ni, Ni; Bud& #x27; ko, Sergey; Canfield, Paul

    2013-05-28

    Method of making a low resistivity electrical connection between an electrical conductor and an iron pnictide superconductor involves connecting the electrical conductor and superconductor using a tin or tin-based material therebetween, such as using a tin or tin-based solder. The superconductor can be based on doped AFe.sub.2As.sub.2, where A can be Ca, Sr, Ba, Eu or combinations thereof for purposes of illustration only.

  15. New formation technology for a plasma display panel barrier-rib structure using a precise metal mold fabricated by the UV-LIGA process

    NASA Astrophysics Data System (ADS)

    Son, Seung-Hyun; Park, Yong-Suk; Choi, Sie-Young

    2002-01-01

    We present a new formation technology for a plasma display panel (PDP) barrier-rib structure by which we can obtain a barrier-rib with a high aspect ratio and reduce the manufacturing cost. Firstly, a precise metal mould is manufactured for massively replicating the PDP barrier-rib construction using the UV-LIGA process with a thick negative photoresist (SU-8 50: Microchem Corp). The proposed sequence includes several processes: amorphous silicon as an adhesion layer; dipping into xylene and n-butyl acetate after the development of SU-8; two step removal of the SU-8 layer; rip-off process, etc. The proposed processes produce a copper mould with a high aspect ratio, good surface roughness and a uniform thickness. Secondly, a PDP barrier-rib structure is formed using the roll-pressing method with a reusable metal mould fabricated by the proposed UV-LIGA process. This is a very simple and inexpensive method consisting of printing the barrier-rib paste, drying, roll-pressing and firing. Consequently, by combining the UV-LIGA and roll-pressing processes, the desired barrier-rib shapes can be made with a high aspect ratio and various dimensions. The combination of the UV-LIGA and roll-pressing processes also demonstrates the possibility of achieving two major goals in the barrier-rib processes; i.e., developing a barrier-rib structure with a high aspect ratio that can be applied to high-definition televisions, and reducing the manufacturing cost.

  16. Low-resistivity photon-transparent window attached to photo-sensitive silicon detector

    DOEpatents

    Holland, Stephen Edward

    2000-02-15

    The invention comprises a combination of a low resistivity, or electrically conducting, silicon layer that is transparent to long or short wavelength photons and is attached to the backside of a photon-sensitive layer of silicon, such as a silicon wafer or chip. The window is applied to photon sensitive silicon devices such as photodiodes, charge-coupled devices, active pixel sensors, low-energy x-ray sensors and other radiation detectors. The silicon window is applied to the back side of a photosensitive silicon wafer or chip so that photons can illuminate the device from the backside without interference from the circuit printed on the frontside. A voltage sufficient to fully deplete the high-resistivity photosensitive silicon volume of charge carriers is applied between the low-resistivity back window and the front, patterned, side of the device. This allows photon-induced charge created at the backside to reach the front side of the device and to be processed by any circuitry attached to the front side. Using the inventive combination, the photon sensitive silicon layer does not need to be thinned beyond standard fabrication methods in order to achieve full charge-depletion in the silicon volume. In one embodiment, the inventive backside window is applied to high resistivity silicon to allow backside illumination while maintaining charge isolation in CCD pixels.

  17. Voltage controlling mechanisms in low resistivity silicon solar cells: A unified approach

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Swartz, C. K.; Hart, R. E.; Godlewski, M. P.

    1984-01-01

    An experimental technique capable of resolving the dark saturation current into its base and emitter components is used as the basis of an analysis in which the voltage limiting mechanisms were determined for a variety of high voltage, low resistivity silicon solar cells. The cells studied include the University of Florida hi-low emitter cell, the NASA and the COMSAT multi-step diffused cells, the Spire Corporation ion-implanted emitter cell, and the University of New South Wales MINMIS and MINP cells. The results proved to be, in general, at variance with prior expectations. Most surprising was the finding that the MINP and the MINMIS voltage improvements are due, to a considerable extent, to a previously unrecognized optimization of the base component of the saturation current. This result is substantiated by an independent analysis of the material used to fabricate these devices.

  18. Voltage controlling mechanisms in low resistivity silicon solar cells - A unified approach

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Swartz, C. K.; Hart, R. E.; Godlewski, M. P.

    1984-01-01

    An experimental technique capable of resolving the dark saturation current into its base and emitter components is used as the basis of an analysis in which the voltage limiting mechanisms were determined for a variety of high voltage, low resistivity silicon solar cells. The cells studied include the University of Florida hi-low emitter cell, the NASA and the COMSAT multi-step diffused cells, the Spire Corporation ion-implanted emitter cell, and the University of New South Wales MINMIS and MINP cells. The results proved to be, in general, at variance with prior expectations. Most surprising was the finding that the MINP and the MINMIS voltage improvements are due, to a considerable extent, to a previously unrecognized optimization of the base component of the saturation current. This result is substantiated by an independent analysis of the material used to fabricate these devices.

  19. Formation of extremely low resistance Ti/Pt/Au ohmic contacts to p-GaAs

    NASA Astrophysics Data System (ADS)

    Stareev, G.

    1993-05-01

    Nonalloyed Ti/Pt/Au contacts to heavily doped p-GaAs have been fabricated using effective cleaning of the semiconductor surface by bombardment with low energy Ar+ ions (60 eV) prior to the metal deposition. Short-time annealing cycles for 1 and 20 s were employed in order to restore the primary properties of the subsurface layer disordered during ion bombardment. Annealing at temperatures ranging from 420 to 530 °C provides formation of contacts with an extremely low resistivity of 2.8×10-8 Ω cm2. A definite correlation between electrical properties and structural modifications of the contact interface was found. Measurements of the contact resistivity at different ambient temperatures yielded a good quantitative agreement with the theoretically predicted values using the field-emission model. The results indicate that the metal-semiconductor junctions formed under optimal conditions are intimate and that tunneling is the dominant mechanism of the current flow.

  20. Low-Resistance Ohmic Contacts to p-GaAs

    NASA Astrophysics Data System (ADS)

    Hirano, Makoto; Yanagawa, Fumihiko

    1986-08-01

    A new metal structure consisting of AuZnNi/Ti/Au has been proposed for forming low-resistance ohmic contacts to p-GaAs with a fine-pattern definition. The dependency of the contact resistance on the Ti-layer thickness indicated that an optimum amount of Ti is requred for reducing the contact resistance. A minimun contact resistance (0.3 Ω\\cdotmm) was obtained with 150-nm thick Ti attached to Be-implanted p-GaAs at a dose of 6× 1013 cm-3.

  1. Precision Fit of Screw-Retained Implant-Supported Fixed Dental Prostheses Fabricated by CAD/CAM, Copy-Milling, and Conventional Methods.

    PubMed

    de França, Danilo Gonzaga; Morais, Maria Helena; das Neves, Flávio D; Carreiro, Adriana Fonte; Barbosa, Gustavo As

    The aim of this study was to evaluate the effectiveness of fabrication methods (computer-aided design/computer-aided manufacture [CAD/CAM], copy-milling, and conventional casting) in the fit accuracy of three-unit, screw-retained fixed dental prostheses. Sixteen three-unit implant-supported screw-retained frameworks were fabricated to fit an in vitro model. Eight frameworks were fabricated using the CAD/CAM system, four in zirconia and four in cobalt-chromium. Four zirconia frameworks were fabricated using the copy-milled system, and four were cast in cobalt-chromium using conventional casting with premachined abutments. The vertical and horizontal misfit at the implant-framework interface was measured using scanning electron microscopy at ×250. The results for vertical misfit were analyzed using Kruskal-Wallis and Mann-Whitney tests. The horizontal misfits were categorized as underextended, equally extended, or overextended. Statistical analysis established differences between groups according to the chi-square test (α = .05). The mean vertical misfit was 5.9 ± 3.6 μm for CAD/CAM-fabricated zirconia, 1.2 ± 2.2 μm for CAD/CAM-fabricated cobalt-chromium frameworks, 7.6 ± 9.2 μm for copy-milling-fabricated zirconia frameworks, and 11.8 (9.8) μm for conventionally fabricated frameworks. The Mann-Whitney test revealed significant differences between all but the zirconia-fabricated frameworks. A significant association was observed between the horizontal misfits and the fabrication method. The percentage of horizontal misfits that were underextended and overextended was higher in milled zirconia (83.3%), CAD/CAM cobaltchromium (66.7%), cast cobalt-chromium (58.3%), and CAD/CAM zirconia (33.3%) frameworks. CAD/CAM-fabricated frameworks exhibit better vertical misfit and low variability compared with copy-milled and conventionally fabricated frameworks. The percentage of interfaces equally extended was higher when CAD/CAM and zirconia were used.

  2. Electron and proton damage coefficients in low-resistivity silicon

    NASA Technical Reports Server (NTRS)

    Srour, J. R.; Othmer, S.; Chiu, K. Y.

    1975-01-01

    The electron and proton damage coefficients for low resistivity p-type boron-doped silicon were determined from minority-carrier lifetime measurements on bulk material and diffusion length measurements on solar cells. The bulk samples were irradiated with electrons at three energy levels (0.5, 1.5, and 2.5 MeV) using a Dynamitron. Lifetime measurements were made with a steady-state photoconductivity apparatus, and comparison measurements of diffusion length were obtained using the steady-state surface photovoltage method (Goodman, 1961). The diffusion-length damage coefficients increased with decreasing resistivity for boron-doped silicon; this dependence can be qualitatively accounted for using a two-level Hall-Shockley-Read model. The damage coefficients for solar cells were larger than for their bulk-material counterparts. The damage coefficient was apparently independent of the dislocation density in the 0.1 ohm-cm bulk samples and solar cells investigated.

  3. Full-band error control and crack-free surface fabrication techniques for ultra-precision fly cutting of large-aperture KDP crystals

    NASA Astrophysics Data System (ADS)

    Zhang, F. H.; Wang, S. F.; An, C. H.; Wang, J.; Xu, Q.

    2017-06-01

    Large-aperture potassium dihydrogen phosphate (KDP) crystals are widely used in the laser path of inertial confinement fusion (ICF) systems. The most common method of manufacturing half-meter KDP crystals is ultra-precision fly cutting. When processing KDP crystals by ultra-precision fly cutting, the dynamic characteristics of the fly cutting machine and fluctuations in the fly cutting environment are translated into surface errors at different spatial frequency bands. These machining errors should be suppressed effectively to guarantee that KDP crystals meet the full-band machining accuracy specified in the evaluation index. In this study, the anisotropic machinability of KDP crystals and the causes of typical surface errors in ultra-precision fly cutting of the material are investigated. The structures of the fly cutting machine and existing processing parameters are optimized to improve the machined surface quality. The findings are theoretically and practically important in the development of high-energy laser systems in China.

  4. Low resistance tunnel junctions with remote plasma underoxidized thick barriers

    SciTech Connect

    Ferreira, R.; Freitas, P.P.; MacKenzie, M.; Chapman, J.N.

    2005-05-15

    Low resistance tunnel junctions suitable for >200 Gb/inch{sup 2} read heads require RxA<1 {omega}{mu}m{sup 2} and TMR>10%, usually achieved by natural oxidation with tAl<0.7 nm barriers. This paper shows that as-deposited junctions with competitive electrical and magnetic properties can be produced starting from 0.9 nm Al barriers and remote plasma oxidation in ion beam-deposited stacks using Co{sub 73.8}Fe{sub 16.2}B{sub 10} electrodes. TMR{approx}20% for RxA{approx}2-15 {omega}{mu}m{sup 2} is obtained, while in the RxA{approx}40-140 {omega}{mu}m{sup 2} range TMR can reach 40%-45%, in as-deposited samples. A limited number of junctions exhibits considerably lower RxA values with respect to the average while keeping similar MR (down to 0.44 {omega}{mu}m{sup 2} with 20% and down to 2.2 {omega}{mu}m{sup 2} with 51%)

  5. Split gate SOI trench LDMOS with low-resistance channel

    NASA Astrophysics Data System (ADS)

    Ying-Wang; Wang, Yi-fan; Liu, Yan-juan; Yang-Wang

    2017-02-01

    A split gate SOI trench LDMOSFET (SGT-LDMOS) structure is proposed and the low-resistance channel is introduced to further reduces the specific on-state resistance (Ron,sp). The split gate SOI trench LDMOS with low on-resistance channel (SGTL-LDMOS) structure shows a reduction in specific on-state resistance (Ron,sp) compared to that of a conventional SOI trench LDMOS (CT-LDMOS) and SGT-LDMOS structures. This is due to the increased N-type concentration in the drift region and the lower channel resistance. In addition, the split-gate floating structure in the SGTL-LDMOS also reduces the specific gate-charge (Qg,sp) and increases the breakdown voltage as compared to the CT-LDMOS. As a result, the breakdown voltage (BV) of the SGTL-LDMOS increases from 183 V of the CT-LDMOS to 227 V, the Ron,sp decreases from 43.4 mΩ cm2 to 9.3 mΩ cm2, and the Qg,sp decreases from 78.4 nC/cm2 to 50.0 nC/cm2.

  6. Low resistance splices for HTS devices and applications

    NASA Astrophysics Data System (ADS)

    Lalitha, S. L.

    2017-09-01

    This paper discusses the preparation methodology and performance evaluation of low resistance splices made of the second generation (2G) high-temperature superconductor (HTS). These splices are required in a broad spectrum of HTS devices including a large aperture, high-field solenoid built in the laboratory to demonstrate a superconducting magnetic energy storage (SMES) device. Several pancake coils are assembled in the form of a nested solenoid, and each coil requires a hundred meters or more of 2G (RE)BCO tape. However, commercial availability of this superconductor with a very uniform physical properties is currently limited to shorter piece lengths. This necessitates us having splices to inter-connect the tape pieces within a pancake coil, between adjacent pancake coils, and to attach HTS current leads to the magnet assembly. As a part of the optimization and qualification of splicing process, a systematic study was undertaken to analyze the electrical performance of splices in two different configurations suitable for this magnet assembly: lap joint and spiral joint. The electrical performance is quantified in terms of the resistance of splices estimated from the current-voltage characteristics. It has been demonstrated that a careful application of this splicing technique can generate lap joints with resistance less than 1 nΩ at 77 K.

  7. A study of efficiency in low resistivity silicon solar cells

    NASA Technical Reports Server (NTRS)

    Dunbar, P. M.; Hauser, J. R.

    1976-01-01

    A general device-analysis program has been utilized to study the efficiency of silicon solar cells. The analysis is applied to specific geometries of both n(+)-p and n(+)-p-p(+) solar cells, and involves a numerical solution of the basic transport and continuity equations. This approach allows solutions that are free of typical limiting assumptions involved in solving the device equations as well as solutions relating to lifetime, mobility variations, and diffused-region profiles. The analysis includes available empirical information on diffusion length, mobility, and lifetime as a function of doping, as well as a Gaussian profile for the diffused region. Results are presented which illustrate the limitations of efficiency as a function of doping. It is found that the maximum efficiencies for both types of cell converge at lower resistivities to around 16% with air-mass-zero radiation and a single-layer absorbing-SiO antireflecting film. It is also found that the minority-carrier lifetime, both in the n(+) surface and p-type bulk regions, presents serious limitations to conversion efficiency, particularly in the low-resistivity cells.

  8. A study of efficiency in low resistivity silicon solar cells

    NASA Technical Reports Server (NTRS)

    Dunbar, P. M.; Hauser, J. R.

    1976-01-01

    A general device-analysis program has been utilized to study the efficiency of silicon solar cells. The analysis is applied to specific geometries of both n(+)-p and n(+)-p-p(+) solar cells, and involves a numerical solution of the basic transport and continuity equations. This approach allows solutions that are free of typical limiting assumptions involved in solving the device equations as well as solutions relating to lifetime, mobility variations, and diffused-region profiles. The analysis includes available empirical information on diffusion length, mobility, and lifetime as a function of doping, as well as a Gaussian profile for the diffused region. Results are presented which illustrate the limitations of efficiency as a function of doping. It is found that the maximum efficiencies for both types of cell converge at lower resistivities to around 16% with air-mass-zero radiation and a single-layer absorbing-SiO antireflecting film. It is also found that the minority-carrier lifetime, both in the n(+) surface and p-type bulk regions, presents serious limitations to conversion efficiency, particularly in the low-resistivity cells.

  9. Ultra-precision fabrication of 500 mm long and laterally graded Ru/C multilayer mirrors for X-ray light sources

    SciTech Connect

    Störmer, M. Gabrisch, H.; Horstmann, C.; Heidorn, U.; Hertlein, F.; Wiesmann, J.; Siewert, F.; Rack, A.

    2016-05-15

    X-ray mirrors are needed for beam shaping and monochromatization at advanced research light sources, for instance, free-electron lasers and synchrotron sources. Such mirrors consist of a substrate and a coating. The shape accuracy of the substrate and the layer precision of the coating are the crucial parameters that determine the beam properties required for various applications. In principal, the selection of the layer materials determines the mirror reflectivity. A single layer mirror offers high reflectivity in the range of total external reflection, whereas the reflectivity is reduced considerably above the critical angle. A periodic multilayer can enhance the reflectivity at higher angles due to Bragg reflection. Here, the selection of a suitable combination of layer materials is essential to achieve a high flux at distinct photon energies, which is often required for applications such as microtomography, diffraction, or protein crystallography. This contribution presents the current development of a Ru/C multilayer mirror prepared by magnetron sputtering with a sputtering facility that was designed in-house at the Helmholtz-Zentrum Geesthacht. The deposition conditions were optimized in order to achieve ultra-high precision and high flux in future mirrors. Input for the improved deposition parameters came from investigations by transmission electron microscopy. The X-ray optical properties were investigated by means of X-ray reflectometry using Cu- and Mo-radiation. The change of the multilayer d-spacing over the mirror dimensions and the variation of the Bragg angles were determined. The results demonstrate the ability to precisely control the variation in thickness over the whole mirror length of 500 mm thus achieving picometer-precision in the meter-range.

  10. Ultra-precision fabrication of 500 mm long and laterally graded Ru/C multilayer mirrors for X-ray light sources.

    PubMed

    Störmer, M; Gabrisch, H; Horstmann, C; Heidorn, U; Hertlein, F; Wiesmann, J; Siewert, F; Rack, A

    2016-05-01

    X-ray mirrors are needed for beam shaping and monochromatization at advanced research light sources, for instance, free-electron lasers and synchrotron sources. Such mirrors consist of a substrate and a coating. The shape accuracy of the substrate and the layer precision of the coating are the crucial parameters that determine the beam properties required for various applications. In principal, the selection of the layer materials determines the mirror reflectivity. A single layer mirror offers high reflectivity in the range of total external reflection, whereas the reflectivity is reduced considerably above the critical angle. A periodic multilayer can enhance the reflectivity at higher angles due to Bragg reflection. Here, the selection of a suitable combination of layer materials is essential to achieve a high flux at distinct photon energies, which is often required for applications such as microtomography, diffraction, or protein crystallography. This contribution presents the current development of a Ru/C multilayer mirror prepared by magnetron sputtering with a sputtering facility that was designed in-house at the Helmholtz-Zentrum Geesthacht. The deposition conditions were optimized in order to achieve ultra-high precision and high flux in future mirrors. Input for the improved deposition parameters came from investigations by transmission electron microscopy. The X-ray optical properties were investigated by means of X-ray reflectometry using Cu- and Mo-radiation. The change of the multilayer d-spacing over the mirror dimensions and the variation of the Bragg angles were determined. The results demonstrate the ability to precisely control the variation in thickness over the whole mirror length of 500 mm thus achieving picometer-precision in the meter-range.

  11. Development and fabrication of a hyperspectral, mirror based IR-telescope with ultra-precise manufacturing and mounting techniques for a snap-together system assembly

    NASA Astrophysics Data System (ADS)

    Risse, S.; Scheiding, S.; Gebhardt, A.; Damm, C.; Holota, W.; Eberhardt, R.; Tünnermann, A.

    2011-11-01

    We report on an ultra-precise manufacturing method of a hyperspectral, mirror based IR-Telescope for applications in the Mid-wavelength infrared (MWIR). The proposed method simplifies the otherwise time consuming system alignment by the use of a snap-together assembly technique, that can be used for rotationally symmetric designs such as Korsch or Three Mirror Anastigmatic (TMA) telescope designs. The proposed technology is based on diamond machining of at least two mirror surfaces on one common substrate in one and the same machine setup. A novel hybrid manufacturing approach, which is a combination of diamond turning and diamond milling is used to manufacture fiducials and mounting planes that reduce the adjustment expenditure significantly. Reference elements and interfaces on the substrates are the basis for a precise metrology of the shape and the position of the optical surfaces as well as for the final assembly of the optical bench. The system integration into a hexapod framework is also based on precisely diamond machined stop surfaces to define the air distance and tilt between the mirrors. The presented method is a novel manufacturing and mounting technology for IR-telescope assemblies with diffraction limited optical performance in the MWIR.

  12. Ni2Si nanowires of extraordinarily low resistivity

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Lu, J.; Hellström, P.-E.; Östling, M.; Zhang, S.-L.

    2006-05-01

    Ultralong, polycrystalline Ni2Si nanowires are fabricated by combining sidewall transfer lithography with self-aligned silicidation. Upon formation at 500°C, the nanowires that are 400μm long with a rectangular cross section of 37.5 by 25.3nm are characterized by a resistivity of 25±1μΩcm which is similar to the value for Ni2Si thin films. Further annealing at 800°C results in an extraordinarily low wire resistivity of 10μΩcm. Such a drastic decrease in resistivity is attributed to a significant grain growth and a low density of defects in the nanowires.

  13. Thermally stable, low resistance contact systems for use with shallow junction p(+) nn(+) and n(+)pp(+) InP solar cells

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Fatemi, N. S.; Hoffman, R. W.

    1995-01-01

    Two contact systems for use on shallow junction InP solar cells are described. The feature shared by these two contact systems is the absence of the metallurgical intermixing that normally takes place between the semiconductor and the contact metallization during the sintering process. The n(+)pp(+) cell contact system, consisting of a combination of Au and Ge, not only exhibits very low resistance in the as-fabricated state, but also yields post-sinter resistivity values of 1(exp -7) ohms-sq cm, with effectively no metal-InP interdiffusion. The n(+)pp(+)cell contact system, consisting of a combination of Ag and Zn, permits low resistance ohmic contact to be made directly to a shallow junction p/n InP device without harming the device itself during the contacting process.

  14. Laser Doppler imaging of cutaneous blood flow through transparent face masks: a necessary preamble to computer-controlled rapid prototyping fabrication with submillimeter precision.

    PubMed

    Allely, Rebekah R; Van-Buendia, Lan B; Jeng, James C; White, Patricia; Wu, Jingshu; Niszczak, Jonathan; Jordan, Marion H

    2008-01-01

    A paradigm shift in management of postburn facial scarring is lurking "just beneath the waves" with the widespread availability of two recent technologies: precise three-dimensional scanning/digitizing of complex surfaces and computer-controlled rapid prototyping three-dimensional "printers". Laser Doppler imaging may be the sensible method to track the scar hyperemia that should form the basis of assessing progress and directing incremental changes in the digitized topographical face mask "prescription". The purpose of this study was to establish feasibility of detecting perfusion through transparent face masks using the Laser Doppler Imaging scanner. Laser Doppler images of perfusion were obtained at multiple facial regions on five uninjured staff members. Images were obtained without a mask, followed by images with a loose fitting mask with and without a silicone liner, and then with a tight fitting mask with and without a silicone liner. Right and left oblique images, in addition to the frontal images, were used to overcome unobtainable measurements at the extremes of face mask curvature. General linear model, mixed model, and t tests were used for data analysis. Three hundred seventy-five measurements were used for analysis, with a mean perfusion unit of 299 and pixel validity of 97%. The effect of face mask pressure with and without the silicone liner was readily quantified with significant changes in mean cutaneous blood flow (P < .5). High valid pixel rate laser Doppler imager flow data can be obtained through transparent face masks. Perfusion decreases with the application of pressure and with silicone. Every participant measured differently in perfusion units; however, consistent perfusion patterns in the face were observed.

  15. Integration of microfabricated low resistance and thousand-turn coils for vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Yufeng; Zhao, Lurui; Sok Kim, Eun

    2016-02-01

    This paper presents two microfabrication approaches for multi-layer coils for vibration-energy harvesters. A magnet array is arranged with alternating north- and south-orientation to provide a rapidly changing magnetic field for high electromagnetic energy conversion. Multi-turn spiral coils on silicon wafer are aligned to the magnet array for maximum magnetic flux change. One type of coil is made out of 300 μm-thick copper that is electroplated with silicon mold, and the other is built on 25 μm-thick copper electroplated with photoresist mold. The low resistive coils fabricated by the first approach are integrated in a microfabricated energy harvester of 17  ×  7  ×  1.7 mm3 (=0.2 cm3) weighing 0.8 g, which generates 14.3 μW power output (into 0.7 Ω load) from vibration amplitude of 6 μm at 250 Hz. The latter approach is used to make a 1080-turn coil for a microfabricated electromagnetic energy harvester with magnet array and plastic spring. Though the size and weight of the harvester are only 44  ×  20  ×  6 mm3 (=5.3 cm3) and 12 g, respectively, it generates 1.04 mW power output (into 190 Ω load) when it is vibrated at 75 Hz with vibration amplitude of 220 μm.

  16. Frustrated incomplete donor ionization in ultra-low resistivity germanium films

    SciTech Connect

    Xu, Chi; Menéndez, J.; Senaratne, C. L.; Kouvetakis, J.

    2014-12-08

    The relationship between carrier concentration and donor atomic concentration has been determined in n-type Ge films doped with P. The samples were carefully engineered to minimize non-active dopant incorporation by using specially designed P(SiH{sub 3}){sub 3} and P(GeH{sub 3}){sub 3} hydride precursors. The in situ nature of the doping and the growth at low temperatures, facilitated by the Ge{sub 3}H{sub 8} and Ge{sub 4}H{sub 10} Ge sources, promote the creation of ultra-low resistivity films with flat doping profiles that help reduce the errors in the concentration measurements. The results show that Ge deviates strongly from the incomplete ionization expected when the donor atomic concentration exceeds N{sub d} = 10{sup 17} cm{sup −3}, at which the energy separation between the donor and Fermi levels ceases to be much larger than the thermal energy. Instead, essentially full ionization is seen even at the highest doping levels beyond the solubility limit of P in Ge. The results can be explained using a model developed for silicon by Altermatt and coworkers, provided the relevant model parameter is properly scaled. The findings confirm that donor solubility and/or defect formation, not incomplete ionization, are the major factors limiting the achievement of very high carrier concentrations in n-type Ge. The commercially viable chemistry approach applied here enables fabrication of supersaturated and fully ionized prototypes with potential for broad applications in group-IV semiconductor technologies.

  17. Low Resistance Ohmic Contact for ZnSb Thin Film

    NASA Astrophysics Data System (ADS)

    Yin, Meimei; Zhong, Aihua; Luo, Jingting; Li, Fu; Zheng, Zhuanghao; Fan, Ping

    2017-05-01

    To further improve the performance and power density of thermoelectric devices, the size of the device needs to be scaled down from macroscale to microscale. Different from the macroscale device, the specific contact resistivity ρ c of the metal contact to the microscale device becomes a key point to the device's efficiency. In this study, a P type ZnSb thin film was deposited on glass substrate using a radio frequency magnetron sputtering system, followed by annealing at 325°C in an Ar atmosphere. X-ray diffraction, scanning electron microscopy, and the Hall measurement system were utilized for characterization of the ZnSb. The ohmic contact properties of metallic Co and Mo on the annealed ZnSb thin films were investigated, indicating that metallic Co has a lower specific contact resistivity ρ c to ZnSb. The effect of a diluted HCl-etch prior to Co electrode deposition was also studied. The results show that a HCl-etch is effective for the reduction of the ρ c. The dependence of ρ c on the annealing temperature was also studied. Through HCl-etch and annealing at 200°C, specific contact resistivity ρ c as low as 10-7 Ω cm2 is successfully obtained on the Co electrode, providing a good method to fabricate a highly efficient ZnSb-based micro device.

  18. Fabrication Technology

    SciTech Connect

    Blaedel, K.L.

    1993-03-01

    The mission of the Fabrication Technology thrust area is to have an adequate base of manufacturing technology, not necessarily resident at Lawrence Livermore National Laboratory (LLNL), to conduct the future business of LLNL. The specific goals continue to be to (1) develop an understanding of fundamental fabrication processes; (2) construct general purpose process models that will have wide applicability; (3) document findings and models in journals; (4) transfer technology to LLNL programs, industry, and colleagues; and (5) develop continuing relationships with the industrial and academic communities to advance the collective understanding of fabrication processes. The strategy to ensure success is changing. For technologies in which they are expert and which will continue to be of future importance to LLNL, they can often attract outside resources both to maintain their expertise by applying it to a specific problem and to help fund further development. A popular vehicle to fund such work is the Cooperative Research and Development Agreement with industry. For technologies needing development because of their future critical importance and in which they are not expert, they use internal funding sources. These latter are the topics of the thrust area. Three FY-92 funded projects are discussed in this section. Each project clearly moves the Fabrication Technology thrust area towards the goals outlined above. They have also continued their membership in the North Carolina State University Precision Engineering Center, a multidisciplinary research and graduate program established to provide the new technologies needed by high-technology institutions in the US. As members, they have access to and use of the results of their research projects, many of which parallel the precision engineering efforts at LLNL.

  19. Precision Measurement.

    ERIC Educational Resources Information Center

    Radius, Marcie; And Others

    The manual provides information for precision measurement (counting of movements per minute of a chosen activity) of achievement in special education students. Initial sections give guidelines for the teacher, parent, and student to follow for various methods of charting behavior. It is explained that precision measurement is a way to measure the…

  20. Precision Medicine

    PubMed Central

    Cholerton, Brenna; Larson, Eric B.; Quinn, Joseph F.; Zabetian, Cyrus P.; Mata, Ignacio F.; Keene, C. Dirk; Flanagan, Margaret; Crane, Paul K.; Grabowski, Thomas J.; Montine, Kathleen S.; Montine, Thomas J.

    2017-01-01

    Three key elements to precision medicine are stratification by risk, detection of pathophysiological processes as early as possible (even before clinical presentation), and alignment of mechanism of action of intervention(s) with an individual's molecular driver(s) of disease. Used for decades in the management of some rare diseases and now gaining broad currency in cancer care, a precision medicine approach is beginning to be adapted to cognitive impairment and dementia. This review focuses on the application of precision medicine to address the clinical and biological complexity of two common neurodegenerative causes of dementia: Alzheimer disease and Parkinson disease. PMID:26724389

  1. A very low resistance, non-sintered contact system for use on indium phosphide concentrator/shallow junction solar cells

    NASA Technical Reports Server (NTRS)

    Weizer, Victor G.; Fatemi, Navid S.

    1991-01-01

    An investigation is made into the possibility of providing low resistance contacts to shallow junction InP solar cells which do not require sintering and which do not cause device degradation even when subjected to extended annealing at elevated temperatures. We show that the addition of In to Au contacts in amounts that exceed the solid solubility limit lowers the as-fabricated (unsintered) contact resistivity (R sub c) to the 10(exp -5) ohm cm(exp 2) range. We next consider the contact system Au/Au2P3, which has been shown to exhibit as-fabricated R sub c values in the 10(exp -6) ohm cm(exp 2) range, but which fails quickly when heated. We show that the substitution of a refractory metal (W, Ta) for Au preserves the low R sub c values while preventing the destructive reactions that would normally take place in this system at high temperatures. We show, finally, that R sub c values in the 10(exp -7) ohm cm(exp 2) range can be achieved without sintering by combining the effects of In or Ga additions to Au contacts with the effects of introducing a thin Au2P3 layer at the metal-InP interface.

  2. A very low resistance, non-sintered contact system for use on indium phosphide concentrator/shallow junction solar cells

    NASA Technical Reports Server (NTRS)

    Weizer, Victor G.; Fatemi, Navid S.

    1991-01-01

    An investigation is made into the possibility of providing low resistance contacts to shallow junction InP solar cells which do not require sintering and which do not cause device degradation even when subjected to extended annealing at elevated temperatures. We show that the addition of In to Au contacts in amounts that exceed the solid solubility limit lowers the as-fabricated (unsintered) contact resistivity (R sub c) to the 10(exp -5) ohm cm(exp 2) range. We next consider the contact system Au/Au2P3 which has been shown to exhibit as-fabricated R sub c values in the 10(exp -6) ohm cm(exp 2) range, but which fails quickly when heated. We show that the substitution of a refractory metal (W, Ta) for Au preserves the low R sub c values while preventing the destructive reactions that would normally take place in this system at high temperatures. We show, finally, that R sub c values in the 10(exp -7) ohm cm(exp 2) range can be achieved without sintering by combining the effects of In or Ga additions to Au contacts with the effects of introducing a thin Au2P3 layer at the metal-InP interface.

  3. A very low resistance, non-sintered contact system for use on indium phosphide concentrator/shallow junction solar cells

    NASA Technical Reports Server (NTRS)

    Weizer, Victor G.; Fatemi, Navid S.

    1991-01-01

    An investigation is made into the possibility of providing low resistance contacts to shallow junction InP solar cells which do not require sintering and which do not cause device degradation even when subjected to extended annealing at elevated temperatures. We show that the addition of In to Au contacts in amounts that exceed the solid solubility limit lowers the as-fabricated (unsintered) contact resistivity (R sub c) to the 10(exp -5) ohm cm(exp 2) range. We next consider the contact system Au/Au2P3 which has been shown to exhibit as-fabricated R sub c values in the 10(exp -6) ohm cm(exp 2) range, but which fails quickly when heated. We show that the substitution of a refractory metal (W, Ta) for Au preserves the low R sub c values while preventing the destructive reactions that would normally take place in this system at high temperatures. We show, finally, that R sub c values in the 10(exp -7) ohm cm(exp 2) range can be achieved without sintering by combining the effects of In or Ga additions to Au contacts with the effects of introducing a thin Au2P3 layer at the metal-InP interface.

  4. Two-dimensional low-resistance contacts for high performance WSe2 and MoS2 transistors

    NASA Astrophysics Data System (ADS)

    Chuang, Hsun-Jen

    Two-dimensional layered materials beyond graphene such as transition metal dichalcogenides (TMDs) have attracted a lot of interests due to their superior property in many aspects. In this work, I am focusing on two TMD materials: WSe2 and MoS2. The main objective this work is to develop novel approaches to fabricating low-resistance ohmic contacts to TMDs for low power, high performance electronic applications. First, we used graphene as electrical contacts for WSe2 field-effect transistor with superior performance, including a high ON/OFF ratio of >107 at 170 K, large electron mobility of 330 cm2V-1s -1 and he hole mobility of 270 cm2V-1s -1 at 77 K, and low contact resistance of 2kΩ microm. Second, we developed a novel 2D to 2D contacts strategy2 for a variety of TMDs by van der Waals assembly of substitutionally doped TMDs as drain/source contacts and TMDs with no intentional doping as channel materials. The high intrinsic behavior of the device is revealed, where it exhibits low contact resistances of 0.3 kΩ microm, on/off ratios up to > 109 as well as two-terminal field-effect hole mobility muFE ≈ 2x102 cm2 V-1 s -1 at 300K, which increases to > 6x103 cm 2 V-1 s-1 down to 10K. The 2D/2D low-resistance ohmic contacts presented here represent a new device paradigm that overcomes a significant bottleneck in the performance of TMDs and other 2D materials as the channel materials in post-silicon electronic.

  5. Precision metrology.

    PubMed

    Jiang, X; Whitehouse, D J

    2012-08-28

    This article is a summary of the Satellite Meeting, which followed on from the Discussion Meeting at the Royal Society on 'Ultra-precision engineering: from physics to manufacture', held at the Kavli Royal Society International Centre, Chicheley Hall, Buckinghamshire, UK. The meeting was restricted to 18 invited experts in various aspects of precision metrology from academics from the UK and Sweden, Government Institutes from the UK and Germany and global aerospace industries. It examined and identified metrology problem areas that are, or may be, limiting future developments in precision engineering and, in particular, metrology. The Satellite Meeting was intended to produce a vision that will inspire academia and industry to address the solutions of those open-ended problems identified. The discussion covered three areas, namely the function of engineering parts, their measurement and their manufacture, as well as their interactions.

  6. Voltage-controlling mechanisms in low-resistivity silicon solar cells - A unified approach

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Swartz, C. K.; Hart, R. E.; Godlewski, M. P.

    1986-01-01

    An experimental technique is used to determine the relative values of the base and emitter components of the dark saturation current of six types of high-voltage low-resistivity silicon solar cells. One of the surprising findings is the suggestion that the magnitude of the minority-carrier mobility may be process-dependent.

  7. Precision translator

    DOEpatents

    Reedy, Robert P.; Crawford, Daniel W.

    1984-01-01

    A precision translator for focusing a beam of light on the end of a glass fiber which includes two turning fork-like members rigidly connected to each other. These members have two prongs each with its separation adjusted by a screw, thereby adjusting the orthogonal positioning of a glass fiber attached to one of the members. This translator is made of simple parts with capability to keep adjustment even in condition of rough handling.

  8. Precision translator

    DOEpatents

    Reedy, R.P.; Crawford, D.W.

    1982-03-09

    A precision translator for focusing a beam of light on the end of a glass fiber which includes two turning fork-like members rigidly connected to each other. These members have two prongs each with its separation adjusted by a screw, thereby adjusting the orthogonal positioning of a glass fiber attached to one of the members. This translator is made of simple parts with capability to keep adjustment even in condition of rough handling.

  9. Precision Cosmology

    NASA Astrophysics Data System (ADS)

    Jones, Bernard J. T.

    2017-04-01

    Preface; Notation and conventions; Part I. 100 Years of Cosmology: 1. Emerging cosmology; 2. The cosmic expansion; 3. The cosmic microwave background; 4. Recent cosmology; Part II. Newtonian Cosmology: 5. Newtonian cosmology; 6. Dark energy cosmological models; 7. The early universe; 8. The inhomogeneous universe; 9. The inflationary universe; Part III. Relativistic Cosmology: 10. Minkowski space; 11. The energy momentum tensor; 12. General relativity; 13. Space-time geometry and calculus; 14. The Einstein field equations; 15. Solutions of the Einstein equations; 16. The Robertson–Walker solution; 17. Congruences, curvature and Raychaudhuri; 18. Observing and measuring the universe; Part IV. The Physics of Matter and Radiation: 19. Physics of the CMB radiation; 20. Recombination of the primeval plasma; 21. CMB polarisation; 22. CMB anisotropy; Part V. Precision Tools for Precision Cosmology: 23. Likelihood; 24. Frequentist hypothesis testing; 25. Statistical inference: Bayesian; 26. CMB data processing; 27. Parametrising the universe; 28. Precision cosmology; 29. Epilogue; Appendix A. SI, CGS and Planck units; Appendix B. Magnitudes and distances; Appendix C. Representing vectors and tensors; Appendix D. The electromagnetic field; Appendix E. Statistical distributions; Appendix F. Functions on a sphere; Appendix G. Acknowledgements; References; Index.

  10. Fabricated Elastin.

    PubMed

    Yeo, Giselle C; Aghaei-Ghareh-Bolagh, Behnaz; Brackenreg, Edwin P; Hiob, Matti A; Lee, Pearl; Weiss, Anthony S

    2015-11-18

    The mechanical stability, elasticity, inherent bioactivity, and self-assembly properties of elastin make it a highly attractive candidate for the fabrication of versatile biomaterials. The ability to engineer specific peptide sequences derived from elastin allows the precise control of these physicochemical and organizational characteristics, and further broadens the diversity of elastin-based applications. Elastin and elastin-like peptides can also be modified or blended with other natural or synthetic moieties, including peptides, proteins, polysaccharides, and polymers, to augment existing capabilities or confer additional architectural and biofunctional features to compositionally pure materials. Elastin and elastin-based composites have been subjected to diverse fabrication processes, including heating, electrospinning, wet spinning, solvent casting, freeze-drying, and cross-linking, for the manufacture of particles, fibers, gels, tubes, sheets and films. The resulting materials can be tailored to possess specific strength, elasticity, morphology, topography, porosity, wettability, surface charge, and bioactivity. This extraordinary tunability of elastin-based constructs enables their use in a range of biomedical and tissue engineering applications such as targeted drug delivery, cell encapsulation, vascular repair, nerve regeneration, wound healing, and dermal, cartilage, bone, and dental replacement.

  11. Fabricated elastin

    PubMed Central

    Yeo, Giselle C.; Weiss, Anthony S.

    2015-01-01

    The mechanical stability, elasticity, inherent bioactivity, and self-assembly properties of elastin make it a highly attractive candidate for the fabrication of versatile biomaterials. The ability to engineer specific peptide sequences derived from elastin allows for precise control of these physicochemical and organizational characteristics, and further broadens the diversity of elastin-based applications. Elastin and elastin-like peptides can also be modified or blended with other natural or synthetic moieties, including peptides, proteins, polysaccharides and polymers, to augment existing capabilities or confer additional architectural and biofunctional features to compositionally pure materials. Elastin and elastin-based composites have been subjected to diverse fabrication processes, including heating, electrospinning, wet spinning, solvent casting, freeze-drying, and cross-linking, for the manufacture of particles, fibers, gels, tubes, sheets and films. The resulting materials can be tailored to possess specific strength, elasticity, morphology, topography, porosity, wettability, surface charge and bioactivity. This extraordinary tunability of elastin-based constructs enables their use in a range of biomedical and tissue engineering applications such as targeted drug delivery, cell encapsulation, vascular repair, nerve regeneration, wound healing, and dermal, cartilage, bone and dental replacement. PMID:25771993

  12. Deposition and parametric analysis of RF sputtered ZnO:Al thin films with very low resistivity

    NASA Astrophysics Data System (ADS)

    Jahed, N. M. S.; Mahmoudysepehr, M.; Sivoththaman, S.

    2016-11-01

    RF sputtered, aluminum-doped zinc oxide (ZnO:Al or AZO) is an attractive candidate material as transparent conductive oxides in the fabrication of opto-electronic devices. High electrical conductivity and optical transparency are two key requirements in such applications. This paper reports on the formation of AZO films on glass substrates in an RF-sputtering chamber modified to facilitate in situ heating during deposition. The influence of chamber pressure, RF power, and deposition temperature has been systematically studied and the electrical parameters such as film resistivity, carrier concentration, carrier mobility as well as optical transmission have been analyzed. Film deposition at 250 °C and a low chamber pressure of 0.5 mT resulted in a very low resistivity of 2.94 × 10-4 ohm cm. The structural properties of the films with the lowest resistivity have been further analyzed by x-ray diffraction (XRD) and PL measurements and are compared with the film deposited at room temperature. The XRD results show dominant peaks along (103) orientation for the AZO films with slightly improved crystal quality at higher temperature. Evolution of near band edge and deep level emission photoluminescence peaks also indicate improvement in crystal structure with increased deposition temperature.

  13. Precision Engineering within the National Ignition Campaign

    SciTech Connect

    Taylor, J S; Carlisle, K; Klingmann, J L; Geraghty, P; Saito, T T; Montesanti, R C

    2010-02-17

    In this very brief talk, we'll discuss how precision engineering impacts 4 key areas of NIF: (1) Diamond turning of KDP crystals; (2) Mitigation of laser damage on optics; (3) Alignment of lasers, targets, diagnostics; (4) Target fabrication.

  14. LOW RESISTANCE CONNECTIONS BETWEEN CELLS IN THE DEVELOPING ANTHER OF THE LILY

    PubMed Central

    Spitzer, Nicholas C.

    1970-01-01

    Low resistance junctions were demonstrated between cells in anthers from young buds of Lilium longiflorum Croft by standard electrophysiological techniques. Electrodes containing a dye were used to stain impaled cells for later histological identification. Electrical coupling is widespread; germinal cells are coupled to one another; coupling is also observed between somatic elements, and germinal and somatic cells are similarly interconnected. Cytoplasmic bridges are implicated in the first case; plasmodesmata are probably responsible for the interactions in the other two. Although the physiological role of the low resistance junctions shown here and present in embryonic animal tissues is unknown, the possible function of this form of intercellular communication in the development of the anther is discussed. PMID:4918215

  15. Formation of low resistivity titanium silicide gates in semiconductor integrated circuits

    DOEpatents

    Ishida, Emi

    1999-08-10

    A method of forming a titanium silicide (69) includes the steps of forming a transistor having a source region (58), a drain region (60) and a gate structure (56) and forming a titanium layer (66) over the transistor. A first anneal is performed with a laser anneal at an energy level that causes the titanium layer (66) to react with the gate structure (56) to form a high resistivity titanium silicide phase (68) having substantially small grain sizes. The unreacted portions of the titanium layer (66) are removed and a second anneal is performed, thereby causing the high resistivity titanium silicide phase (68) to convert to a low resistivity titanium silicide phase (69). The small grain sizes obtained by the first anneal allow low resistivity titanium silicide phase (69) to be achieved at device geometries less than about 0.25 micron.

  16. Low resistivity metal silicide nanowires with extraordinarily high aspect ratio for future nanoelectronic devices.

    PubMed

    Chen, Sheng-Yu; Yeh, Ping-Hung; Wu, Wen-Wei; Chen, Uei-Shin; Chueh, Yu-Lun; Yang, Yu-Chen; Gwo, Shangir; Chen, Lih-Juann

    2011-11-22

    One crucial challenge for the integrated circuit devices to go beyond the current technology has been to find the appropriate contact and interconnect materials. NiSi has been commonly used in the 45 nm devices mainly because it possesses the lowest resistivity among all metal silicides. However, for devices of even smaller dimension, its stability at processing temperature is in doubt. In this paper, we show the growth of high-quality nanowires of NiSi(2), which is a thermodynamically stable phase and possesses low resistivity suitable for future generation electronics devices. The origin of low resistivity for the nanowires has been clarified to be due to its defect-free single-crystalline structure instead of surface and size effects. © 2011 American Chemical Society

  17. Plasma-enhanced chemical vapor deposition of low-resistive tungsten thin films

    SciTech Connect

    Kim, Y.T.; Min, S.; Hong, J.S. ); Kim, C.K. )

    1991-02-25

    Controlling the wafer temperatures from 200 to 500 {degree}C at H{sub 2}/WF{sub 6} flow ratio equal to 24, low-resistive (about 11 {mu}{Omega} cm) tungsten thin films are deposited by plasma-enhanced chemical vapor deposition. The as-deposited tungsten films have (110), (200), and (211) oriented bcc structures and Auger depth profile shows that fluorine and oxygen impurities are below the detection limit of Auger electron spectroscopy.

  18. Direct Deposition of Low Resistance Thermally Stable Ohmic Contacts to n-SiC

    DTIC Science & Technology

    2001-06-01

    Direct Deposition of Low Resistance Thermally Stable Ohmic Contacts to n-SiC by M. W. Cole, P. C. Joshi, M. H . Ervin, J. D. Demaree, M...SiC M. W. Cole, P. C. Joshi, J. D. Demaree, C. W. Hubbard, and J. K. Hirvonen Weapons and Materials Research Directorate, ARL M. H . Ervin and...device operation. ii Acknowledgments The authors would like to acknowledge H . Kim, A. Pique, D. B. Chrisey, C. K. Richardson, and M. H . Wisnioski

  19. Low-Resistance 2D/2D Ohmic Contacts: A Universal Approach to High-Performance WSe2, MoS2, and MoSe2 Transistors.

    PubMed

    Chuang, Hsun-Jen; Chamlagain, Bhim; Koehler, Michael; Perera, Meeghage Madusanka; Yan, Jiaqiang; Mandrus, David; Tománek, David; Zhou, Zhixian

    2016-03-09

    We report a new strategy for fabricating 2D/2D low-resistance ohmic contacts for a variety of transition metal dichalcogenides (TMDs) using van der Waals assembly of substitutionally doped TMDs as drain/source contacts and TMDs with no intentional doping as channel materials. We demonstrate that few-layer WSe2 field-effect transistors (FETs) with 2D/2D contacts exhibit low contact resistances of ∼0.3 kΩ μm, high on/off ratios up to >10(9), and high drive currents exceeding 320 μA μm(-1). These favorable characteristics are combined with a two-terminal field-effect hole mobility μFE ≈ 2 × 10(2) cm(2) V(-1) s(-1) at room temperature, which increases to >2 × 10(3) cm(2) V(-1) s(-1) at cryogenic temperatures. We observe a similar performance also in MoS2 and MoSe2 FETs with 2D/2D drain and source contacts. The 2D/2D low-resistance ohmic contacts presented here represent a new device paradigm that overcomes a significant bottleneck in the performance of TMDs and a wide variety of other 2D materials as the channel materials in postsilicon electronics.

  20. Low-resistance 2D/2D ohmic contacts: A universal approach to high-performance WSe2, MoS2, and MoSe2 transistors

    DOE PAGES

    Chuang, Hsun -Jen; Chamlagain, Bhim; Koehler, Michael; ...

    2016-02-04

    Here, we report a new strategy for fabricating 2D/2D low-resistance ohmic contacts for a variety of transition metal dichalcogenides (TMDs) using van der Waals assembly of substitutionally doped TMDs as drain/source contacts and TMDs with no intentional doping as channel materials. We demonstrate that few-layer WSe2 field-effect transistors (FETs) with 2D/2D contacts exhibit low contact resistances of ~0.3 kΩ μm, high on/off ratios up to >109, and high drive currents exceeding 320 μA μm–1. These favorable characteristics are combined with a two-terminal field-effect hole mobility μFE ≈ 2 × 102 cm2 V–1 s–1 at room temperature, which increases to >2more » × 103 cm2 V–1 s–1 at cryogenic temperatures. We observe a similar performance also in MoS2 and MoSe2 FETs with 2D/2D drain and source contacts. The 2D/2D low-resistance ohmic contacts presented here represent a new device paradigm that overcomes a significant bottleneck in the performance of TMDs and a wide variety of other 2D materials as the channel materials in postsilicon electronics.« less

  1. Ultra-precision processes for optics manufacturing

    NASA Astrophysics Data System (ADS)

    Martin, William R.

    1991-12-01

    The Optics MODIL (Manufacturing Operations Development and Integration Laboratory) is developing advanced manufacturing technologies for fabrication of ultra precision optical components, aiming for a ten-fold improvement in precision and a shortening of the scheduled lead time. Current work focuses on diamond single point turning, ductile grinding, ion milling, and in/on process metrology.

  2. Ultra-precision processes for optics manufacturing

    NASA Technical Reports Server (NTRS)

    Martin, William R.

    1991-01-01

    The Optics MODIL (Manufacturing Operations Development and Integration Laboratory) is developing advanced manufacturing technologies for fabrication of ultra precision optical components, aiming for a ten-fold improvement in precision and a shortening of the scheduled lead time. Current work focuses on diamond single point turning, ductile grinding, ion milling, and in/on process metrology.

  3. Low resistivity and permeability in actively deforming shear zones on the San Andreas Fault at SAFOD

    USGS Publications Warehouse

    Morrow, Carolyn A.; Lockner, David A.; Hickman, Stephen H.

    2015-01-01

    The San Andreas Fault Observatory at Depth (SAFOD) scientific drillhole near Parkfield, California crosses the San Andreas Fault at a depth of 2.7 km. Downhole measurements and analysis of core retrieved from Phase 3 drilling reveal two narrow, actively deforming zones of smectite-clay gouge within a roughly 200 m-wide fault damage zone of sandstones, siltstones and mudstones. Here we report electrical resistivity and permeability measurements on core samples from all of these structural units at effective confining pressures up to 120 MPa. Electrical resistivity (~10 ohm-m) and permeability (10-21 to 10-22 m2) in the actively deforming zones were one to two orders of magnitude lower than the surrounding damage zone material, consistent with broader-scale observations from the downhole resistivity and seismic velocity logs. The higher porosity of the clay gouge, 2 to 8 times greater than that in the damage zone rocks, along with surface conduction were the principal factors contributing to the observed low resistivities. The high percentage of fine-grained clay in the deforming zones also greatly reduced permeability to values low enough to create a barrier to fluid flow across the fault. Together, resistivity and permeability data can be used to assess the hydrogeologic characteristics of the fault, key to understanding fault structure and strength. The low resistivities and strength measurements of the SAFOD core are consistent with observations of low resistivity clays that are often found in the principal slip zones of other active faults making resistivity logs a valuable tool for identifying these zones.

  4. Origins of low resistivity in Al ion-implanted ZnO bulk single crystals

    SciTech Connect

    Oga, T.; Izawa, Y.; Kuriyama, K.; Kushida, K.; Kinomura, A.

    2011-06-15

    The origins of low resistivity in Al ion-implanted ZnO bulk single crystals are studied by combining Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA), photoluminescence (PL), and Van der Pauw methods. The Al-ion implantation (peak concentration: 2.6 x 10{sup 20}cm{sup -3}) into ZnO is performed using a multiple-step energy. The resistivity decreases from {approx}10{sup 4{Omega}} cm for un-implanted ZnO to 1.4 x 10{sup -1{Omega}} cm for as-implanted, and reaches 6.0 x 10{sup -4{Omega}} cm for samples annealed at 1000 deg. C. RBS and NRA measurements for as-implanted ZnO suggest the existence of the lattice displacement of Zn (Zn{sub i}) and O (O{sub i}), respectively. After annealing at 1000 deg. C, the Zn{sub i} related defects remain and the O{sub i} related defects disappear. The origin of the low resistivity in the as-implanted sample is attributed to the Zn{sub i} ({approx}30 meV [Look et al., Phys. Rev. Lett. 82, 2552 (1999)]). In contrast, the origin of the low resistivity in the sample annealed at 1000 deg. C is assigned to both of the Zn{sub i} related defects and the electrically activated Al donor. A new PL emission appears at around 3.32 eV after annealing at 1000 deg. C, suggesting electrically activated Al donors.

  5. Microbiopsy/precision cutting devices

    DOEpatents

    Krulevitch, P.A.; Lee, A.P.; Northrup, M.A.; Benett, W.J.

    1999-07-27

    Devices are disclosed for performing tissue biopsy on a small scale (microbiopsy). By reducing the size of the biopsy tool and removing only a small amount of tissue or other material in a minimally invasive manner, the risks, costs, injury and patient discomfort associated with traditional biopsy procedures can be reduced. By using micromachining and precision machining capabilities, it is possible to fabricate small biopsy/cutting devices from silicon. These devices can be used in one of four ways (1) intravascularly, (2) extravascularly, (3) by vessel puncture, and (4) externally. Additionally, the devices may be used in precision surgical cutting. 6 figs.

  6. Microbiopsy/precision cutting devices

    DOEpatents

    Krulevitch, Peter A.; Lee, Abraham P.; Northrup, M. Allen; Benett, William J.

    1999-01-01

    Devices for performing tissue biopsy on a small scale (microbiopsy). By reducing the size of the biopsy tool and removing only a small amount of tissue or other material in a minimally invasive manner, the risks, costs, injury and patient discomfort associated with traditional biopsy procedures can be reduced. By using micromachining and precision machining capabilities, it is possible to fabricate small biopsy/cutting devices from silicon. These devices can be used in one of four ways 1) intravascularly, 2) extravascularly, 3) by vessel puncture, and 4) externally. Additionally, the devices may be used in precision surgical cutting.

  7. Coalescence of magnetic islands in the low-resistivity, Hall-MHD regime.

    PubMed

    Knoll, D A; Chacón, L

    2006-04-07

    The coalescence of magnetic islands in the low-resistivity eta, Hall-MHD regime is studied. The interaction between the ion inertial length d(i) and the dynamically evolving current sheet scale length deltaJ is established. Initially, d(i) < deltaJ. If eta is such that deltaJ dynamically thins down to d(i) prior to the well-known sloshing phenomena, then sloshing is avoided. This results in eta independent peak reconnection rates. However, if d(i) is small enough that deltaJ cannot be thinned down to this scale prior to sloshing, then sloshing proceeds as in the resistive MHD model.

  8. Low resistivity contacts to YBa2Cu3O(7-x) superconductors

    NASA Technical Reports Server (NTRS)

    Hsi, Chi-Shiung; Haertling, Gene H.

    1991-01-01

    Silver, gold, platinum, and palladium metals were investigated as electroding materials for the YBa2Cu3O(7-x) superconductors. Painting, embedding, and melting techniques were used to apply the electrodes. Contact resistivities were determined by: (1) type of electrode; (2) firing conditions; and (3) application method. Electrodes fired for long times exhibited lower contact resistivities than those fired for short times. Low-resistivity contacts were found for silver and gold electrodes. Silver, which made good ohmic contact to the YBa2Cu3O(7-x) superconductor with low contact resistivities was found to be the best electroding material among the materials evaluated in this investigation.

  9. Low-Resistant Band-Passing Noise and Its Dynamical Effects

    NASA Astrophysics Data System (ADS)

    Bai, Zhan-Wu

    2007-07-01

    We propose an n-order noise, which is realized by driving an n-order linear differential equation with a Gaussian white noise. The time-derivative noise is a low-resistant band-passing noise. If the derivative noise is regarded as a thermal one, the system has a vanishing effective friction and it should induce ballistic diffusion of a free particle at long times. The simulation method for the generalized Langevin equation driven by the n-order noise is discussed systematically. The features of three-order derivative noises are presented when they are applied to a ratchet system.

  10. Prompt and Precise Prototyping

    NASA Technical Reports Server (NTRS)

    2003-01-01

    For Sanders Design International, Inc., of Wilton, New Hampshire, every passing second between the concept and realization of a product is essential to succeed in the rapid prototyping industry where amongst heavy competition, faster time-to-market means more business. To separate itself from its rivals, Sanders Design aligned with NASA's Marshall Space Flight Center to develop what it considers to be the most accurate rapid prototyping machine for fabrication of extremely precise tooling prototypes. The company's Rapid ToolMaker System has revolutionized production of high quality, small-to-medium sized prototype patterns and tooling molds with an exactness that surpasses that of computer numerically-controlled (CNC) machining devices. Created with funding and support from Marshall under a Small Business Innovation Research (SBIR) contract, the Rapid ToolMaker is a dual-use technology with applications in both commercial and military aerospace fields. The advanced technology provides cost savings in the design and manufacturing of automotive, electronic, and medical parts, as well as in other areas of consumer interest, such as jewelry and toys. For aerospace applications, the Rapid ToolMaker enables fabrication of high-quality turbine and compressor blades for jet engines on unmanned air vehicles, aircraft, and missiles.

  11. Elastic and Electrical Properties Evaluation of Low Resistivity Pays in Malay Basin Clastics Reservoirs

    NASA Astrophysics Data System (ADS)

    Almanna Lubis, Luluan; Ghosh, Deva P.; Hermana, Maman

    2016-07-01

    The elastic and electrical properties of low resistivity pays clastics reservoirs in Malay Basin are strongly dependent on the complex nature of the clay content, either dispersed or laminated/layered. Estimating the hydrocarbon pore volume from conventional electrical log, i.e. resistivity log, is quite a challenge. The low elastic impedance contrast also found as one of the challenge thus create a problem to map the distribution of the low resistivity reservoirs. In this paper, we evaluate the electrical properties and elastic rock properties to discriminate the pay from the adjacent cap rock or shale. Forward modeling of well log responses including electrical properties are applied to analyze the nature of the possible pays on laminated reservoir rocks. In the implementation of rock properties analysis, several conventional elastic properties are comparatively analyzed for the sensitivity and feasibility analysis on each elastic parameters. Finally, we discussed the advantages of each elastic parameters in detail. In addition, cross-plots of elastic and electrical properties attributes help us in the clear separation of anomalous zone and lithologic properties of sand and shale facies over conventional elastic parameter crossplots attributes. The possible relationship on electrical and elastic properties are discussed for further studies.

  12. An integrated workflow to characterize and evaluate low resistivity pay and its phenomenon in a sandstone reservoir

    NASA Astrophysics Data System (ADS)

    Pratama, Edo; Suhaili Ismail, Mohd; Ridha, Syahrir

    2017-06-01

    The identification, characterization and evaluation of low resistivity pay is very challenging and important for the development of oil and gas fields. Proper identification and characterization of these reservoirs is essential for recovering their reserves. There are many reasons for low resistivity pay zones. It is crucial to identify the origin of this phenomenon. This paper deals with the identification, characterization and evaluation of low resistivity hydrocarbon-bearing sand reservoirs in order to understand the low resistivity phenomenon in a sandstone reservoir, the characterization of the rock types and how to conduct petrophysical analysis to accurately obtain petrophysical properties. An integrated workflow based on petrographical, rock typing and petrophysical methods is conducted and applied. From the integrated analysis that was performed, the presence of illite and a mixed layer of illite-smectite clay minerals in sandstone formation and pyrite-siderite conductive minerals was identified as one of the main reasons for low resistivity occurence in sandstone reservoirs. These clay minerals are distributed as a laminated-dispersed shale distribution model in sandstone reservoirs. The dual water method is recommended to calculate water saturation in low resistivity hydrocarbon-bearing sand reservoirs as this method is more accurate and does not result in an over estimation in water saturation calculation.

  13. Polyimide/graphene nanocomposite materials to construct a low resistive RPC

    NASA Astrophysics Data System (ADS)

    Han, R.; Yan, J. Y.; Tian, G. F.; shen, Z. C.; Liao, B.; Liu, Q.

    2016-11-01

    The development of low resistivity material to increase the rate capability of Resistive Plate Chambers (RPCs) has been attracting more and more attention recently. This paper presents a new type of such a material. The new material is based on polyimide doped with carbon. The electrical volume resistivity of this material could be controlled using different percentages of the doping carbon. The standard thickness of polyimide carbon films is around 40 μm which does not allow to use it as such to build the RPC electrodes. To overcome this, we developed a new stress method to make the gap between two polyimide carbon films. In this paper we will introduce the new detector material, the new type of RPC and the cosmic bench test results. In the future, if the polyimide is widely used in RPCs, the electrical properties changed by high energy particles should be well-studied.

  14. TEM measurement in a low resistivity overburden performed by using low temperature SQUID

    NASA Astrophysics Data System (ADS)

    Ji, Yanju; Du, Shangyu; Xie, Lijun; Chang, Kai; Liu, Yang; Zhang, Yi; Xie, Xiaoming; Wang, Yuan; Lin, Jun; Rong, Liangliang

    2016-12-01

    Exploration of areas with thick low resistivity overburden is still a challenge for time domain transient electromagnetic method (TEM). We report modeling of a sandwich-layered earth by simulating the B field response with different conductive target layer thicknesses, thus obtaining a relationship between the resolution of the B field and the exploration depth. A low temperature Superconducting Quantum Interference Device (SQUID) is an ideal sensor for measuring the secondary magnetic field B in TEM measurements, because its sensitivity of several fT/√Hz is independent of frequency. In our TEM experiments, we utilized two different coils as receivers, a simple SQUID system, and a large transmitter loop of 200 × 200 m2 to compare the detected decay curves. At some measurement points, a decay signal of more than 300 ms duration was obtained by using the SQUID. Apparent resistivity profiles of about 9 km length are presented.

  15. Analysis of the Superconducting Cable Transposition in Low Resistance CICC Joint

    NASA Astrophysics Data System (ADS)

    Zhu, You-hua

    2000-08-01

    In an integrated structure low resistance CICC joint, current is conducted by outer cable strands coming into touch with the conductive Cu sole. So it is an important condition for satisfying joint performance that each strand of the cable inside the joint is able to come to the outermost by transposition. This paper presents analysis, calculation and figures for the strand transposition. According to the twist procedures of the superconducting cable, the author computed the actual pitch of each stage cable, consecutively computed the projection of each stage cable on the axis of the cable (z axis) and the corresponding twist angle as the z coordinate changes, which is then drawn by AutoCAD. From the results shown in the figures, the minimal cable length, which enables each strand to transpose almost equally to the outermost of the cable in such a length, can be determined as the optimal joint length.

  16. Parametric oscillator based on nonlinear vortex dynamics in low-resistance magnetic tunnel junctions

    NASA Astrophysics Data System (ADS)

    Martin, S. Y.; de Mestier, N.; Thirion, C.; Hoarau, C.; Conraux, Y.; Baraduc, C.; Diény, B.

    2011-10-01

    Radiofrequency vortex spin-transfer oscillators based on magnetic tunnel junctions with very low-resistance area product were investigated. A high power of excitations has been obtained characterized by a power spectral density containing a very sharp peak at the fundamental frequency and a series of harmonics. The observed behavior is ascribed to the combined effect of spin-transfer torque and Oersted-Ampère field generated by the large applied dc current. We furthermore show that the synchronization of a vortex oscillation by applying an ac bias current is mostly efficient when the external frequency is twice the oscillator fundamental frequency. This result is interpreted in terms of a parametric oscillator.

  17. Ultralong single-crystal metallic Ni2Si nanowires with low resistivity.

    PubMed

    Song, Yipu; Schmitt, Andrew L; Jin, Song

    2007-04-01

    Ultralong, single-crystal Ni2Si nanowires sheathed with amorphous silicon oxide were synthesized on a large scale by a chemical vapor transport (CVT) method, using iodine as the transport reagent and Ni2Si powder as the source material. Structural characterization using powder X-ray diffraction, electron microscopy, and energy-dispersive spectroscopy shows that the nanowires have Ni2Si-SiOx core-shell structure with single-crystal Ni2Si core and amorphous silicon oxide shell. The oxide shell is electrically insulating and can be removed by HF etching. Four-terminal electrical measurements show that the single-crystal nanowire has extremely low resistivity of 21 muOmega.cm and is capable of supporting remarkably high failure current density >108 A/cm2. These unique Ni2Si nanowires are very attractive nanoscale building blocks for interconnects and fully silicided (FUSI) gate applications in nanoelectronics.

  18. Low-resistance noble metal contacts to high-temperature superconductors

    NASA Technical Reports Server (NTRS)

    Selim, R.; Caton, R.; Buoncristiani, A. M.; Byvik, C. E.; Edahl, R. A., Jr.

    1990-01-01

    Low-resistance contacts were made to both YBa2Cu3O(7-x) and Bi2BaSr2Cu2O8, and to related superconducting compounds by melting gold or silver pads onto the samples before the final oxygen treatment. Scanning electron microscope studies show that both gold and silver do not diffuse far from the contact area. The surface contact resistivity of the best contacts made by the melting technique has an upper limit value in the 10 to the -8th ohm sq cm range at 77 K. This contact resistivity shows no significant change in its value over a period of 17 months. Furthermore, an electron radiation dose of 5.7 x 10 to the 17th electron/sq cm only doubled the contact resistivity.

  19. Low resistivity WxV1-xO2-based multilayer structure with high temperature coefficient of resistance for microbolometer applications

    NASA Astrophysics Data System (ADS)

    Émond, Nicolas; Hendaoui, Ali; Chaker, Mohamed

    2015-10-01

    Materials that exhibit semiconductor-to-metal phase transition (SMT) are commonly used as sensing layers for the fabrication of uncooled microbolometers. The development of highly responsive microbolometers would benefit from using a sensing material that possesses a large thermal coefficient of resistance (TCR) close to room temperature and a resistivity low enough to compromise between noise reduction and high TCR, while it should also satisfies the requirements of current CMOS technology. Moreover, a TCR that remains constant when the IR camera surrounding temperature varies would contribute to achieve reliable temperature measurements without additional corrections steps for TCR temperature dependence. In this paper, the characteristics of the SMT occurring in undoped and tungsten-doped vanadium dioxide thin films deposited on LaAlO3 (100) substrates are investigated. They are further exploited to fabricate a WxV1-xO2 (0 ≤ x ≤ 2.5) multilayer structure exhibiting a bottom-up gradient of tungsten content. This MLS displays a combination of properties that is promising for application to uncooled microbolometer, such as a large TCR of -10.4%/ °C and low resistivity values ranging from 0.012 to 0.10 Ω-cm over the temperature range 22 °C-42 °C.

  20. Low resistivity W{sub x}V{sub 1−x}O{sub 2}-based multilayer structure with high temperature coefficient of resistance for microbolometer applications

    SciTech Connect

    Émond, Nicolas; Hendaoui, Ali; Chaker, Mohamed

    2015-10-05

    Materials that exhibit semiconductor-to-metal phase transition (SMT) are commonly used as sensing layers for the fabrication of uncooled microbolometers. The development of highly responsive microbolometers would benefit from using a sensing material that possesses a large thermal coefficient of resistance (TCR) close to room temperature and a resistivity low enough to compromise between noise reduction and high TCR, while it should also satisfies the requirements of current CMOS technology. Moreover, a TCR that remains constant when the IR camera surrounding temperature varies would contribute to achieve reliable temperature measurements without additional corrections steps for TCR temperature dependence. In this paper, the characteristics of the SMT occurring in undoped and tungsten-doped vanadium dioxide thin films deposited on LaAlO{sub 3} (100) substrates are investigated. They are further exploited to fabricate a W{sub x}V{sub 1−x}O{sub 2} (0 ≤ x ≤ 2.5) multilayer structure exhibiting a bottom-up gradient of tungsten content. This MLS displays a combination of properties that is promising for application to uncooled microbolometer, such as a large TCR of −10.4%/ °C and low resistivity values ranging from 0.012 to 0.10 Ω-cm over the temperature range 22 °C–42 °C.

  1. Precision powder feeder

    DOEpatents

    Schlienger, M. Eric; Schmale, David T.; Oliver, Michael S.

    2001-07-10

    A new class of precision powder feeders is disclosed. These feeders provide a precision flow of a wide range of powdered materials, while remaining robust against jamming or damage. These feeders can be precisely controlled by feedback mechanisms.

  2. Fabric fastenings

    NASA Technical Reports Server (NTRS)

    Walen, E D; Fisher, R T

    1920-01-01

    The study of aeronautical fabrics has led to a consideration of the best methods of attaching and fastening together such materials. This report presents the results of an investigation upon the proper methods of attaching fabrics to airplane wings. The methods recommended in this report have been adopted by the military services.

  3. Laminated fabric as top electrode for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Steim, R.; Chabrecek, P.; Sonderegger, U.; Kindle-Hasse, B.; Siefert, W.; Kroyer, T.; Reinecke, P.; Lanz, T.; Geiger, T.; Hany, R.; Nüesch, F.

    2015-05-01

    A simple lamination technique for conductive and semitransparent fabrics on top of organic photovoltaic cells is presented. Conductive fabrics consisted of metal wires woven in a fabric with polymeric fibers. The lamination of this conductive fabric with help of a high conductive poly(3,4-ethylenedioxythiophene) polystyrene sulfonate formulation results in well aligned low resistive metal wires as top electrode. Semitransparent flexible organic photovoltaic cells were processed with laminated fabrics as top electrode and sputtered layers of aluminum doped zinc oxide and Ag as bottom electrode. The organic photovoltaic cells showed similar performance when illuminated through the bottom or top electrode. Optical simulations were performed to investigate light scattering effects of the fabric. Results are very promising for photovoltaic and lightning devices as well as for all kinds of devices where semitransparent, highly conductive, and non-vacuum processed electrode materials are needed.

  4. A controllable mechanism of forming extremely low-resistance nonalloyed ohmic contacts to group III-V compound semiconductors

    NASA Astrophysics Data System (ADS)

    Stareev, G.; Künzel, H.; Dortmann, G.

    1993-12-01

    This work refers basically to the detailed understanding of the natural phenomena in real tunneling metal-semiconductor contacts. A mechanism of forming extremely low-resistance nonalloyed Ti/Pt/Au ohmic contacts to a variety of III-V compound semiconductors, e.g., InGaAs, InAs, and GaAs, is presented. Epitaxial layers of either type with different doping levels ranging from 1×1019 to 2×1020 cm-3 were employed in order to determine electrical parameters that guarantee pure tunneling behavior of the contacts. Ti/Pt/Au contacts formed on p-InGaAs Zn doped to 1×1020 cm-3 and on n-InGaAs Si doped to 5×1019 cm-3 yielded a specific contact resistance of 4.8×10-8 and 4.3×10-8 Ω cm2, respectively. The same metallization scheme applied to 4×1019 cm-3 Si-doped n-InAs gave a specific contact resistance of 1.7×10-8 Ω cm2 for the as-deposited and annealed samples. An extremely low value of 2.8×10-8 Ω cm2 was evaluated for contacts on p-GaAs doped with Be to 2×1020 cm-3. The contact properties are discussed in relation to the effect of ion-beam cleaning and postdeposition annealing. Of particular concern was the cleaning of the semiconductor surface with low-energy (60 eV) Ar+ ions for 40 s prior to the metallization process. This opens also the possibility to investigate ion damage defects and trap-assisted increase of the depletion depth. The contact design was based on the concept that the detrimental influence of the ion beam on the semiconductor properties can be neutralized with a proper annealing. It has been demonstrated that even very rapid thermal processing for 1 s at elevated temperatures was sufficient to restore the stoichiometry in the As-depleted subsurface layer arising as a result of ion damage. The fabrication sequences used provide formation of intimate contacts without interfacial films and carrier compensation effects. Optimal processing conditions have been empirically established that stimulate substantially the ohmic behavior of the contacts

  5. Tungsten Contact and Line Resistance Reduction with Advanced Pulsed Nucleation Layer and Low Resistivity Tungsten Treatment

    NASA Astrophysics Data System (ADS)

    Chandrashekar, Anand; Chen, Feng; Lin, Jasmine; Humayun, Raashina; Wongsenakhum, Panya; Chang, Sean; Danek, Michal; Itou, Takamasa; Nakayama, Tomoo; Kariya, Atsushi; Kawaguchi, Masazumi; Hizume, Shunichi

    2010-09-01

    This paper describes electrical testing results of new tungsten chemical vapor deposition (CVD-W) process concepts that were developed to address the W contact and bitline scaling issues on 55 nm node devices. Contact resistance (Rc) measurements in complementary metal oxide semiconductor (CMOS) devices indicate that the new CVD-W process for sub-32 nm and beyond - consisting of an advanced pulsed nucleation layer (PNL) combined with low resistivity tungsten (LRW) initiation - produces a 20-30% drop in Rc for diffused NiSi contacts. From cross-sectional bright field and dark field transmission electron microscopy (TEM) analysis, such Rc improvement can be attributed to improved plugfill and larger in-feature W grain size with the advanced PNL+LRW process. More experiments that measured contact resistance for different feature sizes point to favorable Rc scaling with the advanced PNL+LRW process. Finally, 40% improvement in line resistance was observed with this process as tested on 55 nm embedded dynamic random access memory (DRAM) devices, confirming that the advanced PNL+LRW process can be an effective metallization solution for sub-32 nm devices.

  6. Research on Magnetic Model of Low Resistance Permanent Magnet Pipe Belt Conveyor

    NASA Astrophysics Data System (ADS)

    Wang, Shuang; Li, De-yong; Guo, Yong-cun

    2016-09-01

    In view of the feasibility of a new type of low resistance permanent magnet pipe belt conveyor, the magnetic properties of the permanent magnet magnetic pipe conveyor belt system are studied. Based on the molecular current hypothesis, the mathematical model of the three dimensional radial magnetic force of permanent magnet pipe conveyor belt was established. The mathematical model of the radial magnetic force was derived, and the influence factors of the radial magnetic force were derived. The finite element simulation of permanent magnet-magnetic pipe conveyor belt magnetic model was carried out, then the magnetic flux density distribution chart under the conditions of different remanence intensity of different permanent magnet and different lengths of the permanent magnets (along the transport direction) were obtained. The simulation results are consistent with the calculation results, which shows that the permanent magnet pipe belt conveyor is feasible. Under certain conditions, the radial magnetic force has nonlinear increase relations with residual magnetism of permanent magnet and the length of the permanent magnet (along the transport direction).

  7. Radiation Effects of n-type, Low Resistivity, Spiral Silicon Drift Detector Hybrid Systems

    SciTech Connect

    Chen W.; De Geronimo G.; Carini, G.A.; Gaskin, J.A.; Keister, J.W.; Li, S.; Li, Z.; Ramsey, B.D.; Siddons, D.P.; Smith, G.C.; Verbitskaya, E.

    2011-11-15

    We have developed a new thin-window, n-type, low-resistivity, spiral silicon drift detector (SDD) array - to be used as an extraterrestrial X-ray spectrometer (in varying environments) for NASA. To achieve low-energy response, a thin SDD entrance window was produced using a previously developed method. These thin-window devices were also produced on lower resistivity, thinner, n-type, silicon material, effectively ensuring their radiation hardness in anticipation of operation in potentially harsh radiation environments (such as found around the Jupiter system). Using the Indiana University Cyclotron Facility beam line RERS1, we irradiated a set of suitable diodes up to 5 Mrad and the latest iteration of our ASICs up to 12 Mrad. Then we irradiated two hybrid detectors consisting of newly, such-produced in-house (BNL) SDD chips bonded with ASICs with doses of 0.25 Mrad and 1 Mrad. Also we irradiated another hybrid detector consisting of previously produced (by KETEK) on n-type, high-resistivity SDD chip bonded with BNL's ASICs with a dose of 1 Mrad. The measurement results of radiated diodes (up to 5 Mrad), ASICs (up to 12 Mrad) and hybrid detectors (up to 1 Mrad) are presented here.

  8. Position-sensitive proportional counter with low-resistance metal-wire anode

    DOEpatents

    Kopp, Manfred K.

    1980-01-01

    A position-sensitive proportional counter circuit is provided which allows the use of a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counter. A pair of specially designed active-capacitance preamplifiers are used to terminate the anode ends wherein the anode is treated as an RC line. The preamplifiers act as stabilized active capacitance loads and each is composed of a series-feedback, low-noise amplifier, a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at the anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction and handling of the anodes, and stabilizes the anode resistivity at high count rates (>10.sup.6 counts/sec).

  9. Uncovering secrets behind low-resistance planing craft hull forms through optimization

    NASA Astrophysics Data System (ADS)

    Mohamad Ayob, Ahmad F.; Ray, Tapabrata; Smith, Warren F.

    2011-11-01

    There has always been significant interest within the naval architectural research community to identify ship hull forms with low resistance. While numerous design optimization frameworks have been proposed over the years to support the activity, very little attention has been paid towards the process of gaining an understanding of 'what makes a good ship design superior?'. Furthermore, there have been limited attempts to identify computationally cheap indicators that can be used to distinguish between good and poor designs. A recent technique named discovery of innovative design principles, which is aimed at understanding the relationship between the design variables, is incorporated in this work. In this article, optimal high-speed planing craft hull forms with minimum calm-water resistance are identified through the use of three state-of-the-art optimization algorithms. Collections of such designs are then used to uncover insights into the underlying relationships between the variables. The importance of such relationships is further analysed to identify computationally cheap performance indicators that can be used in lieu of detailed calm-water resistance calculations. Such indicators are useful at the concept and preliminary design stages, where one needs to sieve efficiently through a number of candidate designs to identify the better ones for further analysis.

  10. Low resistivity, low contrast pays: Part I - concepts and methodology for identification and evaluation

    SciTech Connect

    Sneider, R.M. ); Kulha, J.T. )

    1994-07-01

    Major hydrocarbon accumulations have been found and produced in low resistivity, low contrast (LRLC) sands in the Gulf of Mexico Basin (GOM). In the past in the GOM, LRLC reservoirs were commonly considered wet, tight, misidentified as a shale, or overlooked. Examples of many offshore GOM producing wells are documented now in a joint publication of the Houston and New Orleans geological societies. These examples provide models for identification and evaluation of wells with similar geologic-petrophysical occurrence in the world, including southeast Asia. LRLC pays in the GOM are caused by one or more of the following: (1) thin beds or laminae of clean sands alternating with shales, silts, or shaly sands, (2) clay-coated sands, (3) glauconite-rich sands, (4) sands with interstitial dispersed clay, (5) sands with disseminated pyrite or other conductive minerals, (6) clay-lined burrows, (7) clay clasts in clean sand, (8) altered volcanic/feldspathic framework grains, and (9) very fine-grained sand with very saline water. Similar types of LRLC pay and potential pay sands are being recognized in Indonesia, Malaysia, Australia, Philippines, and Korea. Common depositional systems containing LRLC production in the GOM are (1) deep-water fans, including levee-channel complexes, (2) delta front and toe deposits, (3) shingle turbidites, and (4) alluvial and deltaic channel fills. Similar depositional systems are found in southeast Asia.

  11. Ageing tests on the low-resistivity RPC for the ALICE dimuon arm

    NASA Astrophysics Data System (ADS)

    Arnaldi, R.; Baldit, A.; Barret, V.; Bastid, N.; Blanchard, G.; Chiavassa, E.; Cortese, P.; Crochet, Ph.; Dellacasa, G.; De Marco, N.; Drancourt, C.; Dupieux, P.; Espagnon, B.; Ferretti, A.; Forestier, B.; Gallio, M.; Genoux-Lubain, A.; Insa, C.; Jouve, F.; Lamoine, L.; Lefevre, F.; Manso, F.; Mereu, P.; Musso, A.; Oppedisano, C.; Piccotti, A.; Poggio, F.; Royer, L.; Rosnet, Ph.; Saturnini, P.; Scalas, E.; Scomparin, E.; Sigaudo, F.; Travaglia, G.; Vercellin, E.; Alice Collaboration

    2003-08-01

    The trigger for the Dimuon Forward Spectrometer of the forthcoming ALICE experiment at CERN LHC will be provided by low-resistivity, single gap Resistive Plate Chambers working in streamer mode. Different ageing test were performed to measure and improve the life-time of the detector. Dummy chambers have been built to understand the effects of continuous gas flow upon the Bakelite resistivity: the results concerning our standard gas mixture (49% Ar, 40% forane, 7% isobutane and 4% SF 6) are reported, and compared with the same mixture in which ˜1% of water vapor is added. Moreover, two ageing test of 1 month each have been carried out at the Gamma Irradiation Facility at CERN during 2001. The efficiency for cosmic rays under γ irradiation of RPCs coated with different thicknesses of linseed oil was measured. After protracted operation, the detectors have shown an increase of the current and of the background rate. The increase is slower in the chamber with a thicker oil coating.

  12. Radiation effects of n-type, low resistivity, spiral silicon drift detector hybrid systems

    SciTech Connect

    Chen, W.; Carini, G. A.; De Geronimo, G.; Gaskin, J. A.; Keister, J. W.; Li, S.; Li, Z.; Ramsey, B. D.; Siddons, D. P.; Smith, G. C.; Verbitskaya, E.

    2011-10-01

    We have developed a new thin-window, n-type, low-resistivity, spiral silicon drift detector (SDD) array - to be used as an extraterrestrial X-ray spectrometer (in varying environments) for NASA. To achieve low-energy response, a thin SDD entrance window was produced using a previously developed method. These thin-window devices were also produced on lower resistivity, thinner, n-type, silicon material, effectively ensuring their radiation hardness in anticipation of operation in potentially harsh radiation environments (such as found around the Jupiter system). Using the Indiana University Cyclotron Facility beam line RERS1, we irradiated a set of suitable diodes up to 5 Mrad and the latest iteration of our ASICs up to 12 Mrad. Then we irradiated two hybrid detectors consisting of newly, such-produced in-house (BNL) SDD chips bonded with ASICs with doses of 0.25 Mrad and 1 Mrad. Also we irradiated another hybrid detector consisting of previously produced (by KETEK) on n-type, high-resistivity SDD chip bonded with BNL's ASICs with a dose of 1 Mrad. The measurement results of radiated diodes (up to 5 Mrad), ASICs (up to 12 Mrad) and hybrid detectors (up to 1 Mrad) are presented here.

  13. Tailored emitter, low-resistivity, ion-implanted silicon solar cells

    NASA Technical Reports Server (NTRS)

    Minnucci, J. A.; Kirkpatrick, A. R.; Matthei, K. W.

    1980-01-01

    Open-circuit voltages as high as 0.645 V (AM0, 25 C) have been obtained by a new process developed for low-resistivity silicon. The process utilizes high-dose phosphorus implantation followed by furnace annealing and simultaneous oxide growth. The effect of the thermally grown oxide is a reduction of surface recombination velocity; the oxide also acts as a moderately efficient antireflection (AR) coating. Boron-doped, float-zone silicon with resistivities from 0.1 to 1.0 (omega)(cm) has been processed according to this sequence; results show that the highest open-circuit voltage is obtained with 0.1(omega)(cm) starting material. The effects of Auger recombination and bandgap narrowing caused by high doping concentrations in the n(+)junction region have been investigated by implanting phosphorus over a wide range of dose levels. The effects of emitter-phosphorus concentrations tailored to optimize electric fields in the emitter have also been investigated.

  14. Application of nuclear magnetic resonance logs for evaluating low-resistivity reservoirs: a case study from the Cambay basin, India

    NASA Astrophysics Data System (ADS)

    Chatterjee, Rima; Datta Gupta, Saurabh; Farooqui, M. Y.

    2012-10-01

    Low-resistivity pay sands have been identified in four wells, namely: AM-7, AM-8, TA-1 and TA-5, which penetrate the Eocene pay-IV (EP-IV) sand unit of the Kalol formation in the Cambay basin. These wells are located near the Dholka and Kanwara oilfields in the Cambay basin. The main objective of this paper is to evaluate nuclear magnetic resonance (NMR) logs of the low-resistivity reservoirs from these four wells and to determine the petrophysical properties more accurately than conventional logs have done. The thickness of low-resistivity sand varies from 5 to 17 m in the wells under the study area. The formation has been characterized by a high surface area; thus irreducible water saturation (Swi) is high. The resistivity of these pay zones varies from 1 to 8 Ωm and the total NMR porosity ranges from 15% to 50%. The free fluid porosity ranges from 2% to 5% in wells TA-1 and TA-5 and 12-20% in wells AM-7 and AM-8. The Timur-Coates/SDR model derived that the permeability of the low-resistivity reservoir ranges from 0.8 to 1.5 md in wells TA-1 and TA-5 and 10-110 md in wells AM-7 and AM-8.

  15. Photovoltaic fabrics

    DTIC Science & Technology

    2015-04-22

    during wire fabrication. Weaving was demonstrated for both military-type nylon -cotton blend (NYCO) warp fibers and cotton-polyester warp fibers. A...Lowell, MA 01852 14. ABSTRACT This report describes a project to improve photovoltaic fabrics. It had four objectives: 1) Efficiency – make PV wires on...a continuous basis that exhibit 7% efficiency; 2) Automated Welding – demonstrate an automated means of interconnecting the electrodes of one wire

  16. Low resistivity ZnO-GO electron transport layer based CH{sub 3}NH{sub 3}PbI{sub 3} solar cells

    SciTech Connect

    Ahmed, Muhammad Imran E-mail: amirhabib@scme.nust.edu.pk; Hussain, Zakir; Mujahid, Mohammad; Khan, Ahmed Nawaz; Javaid, Syed Saad; Habib, Amir E-mail: amirhabib@scme.nust.edu.pk

    2016-06-15

    Perovskite based solar cells have demonstrated impressive performances. Controlled environment synthesis and expensive hole transport material impede their potential commercialization. We report ambient air synthesis of hole transport layer free devices using ZnO-GO as electron selective contacts. Solar cells fabricated with hole transport layer free architecture under ambient air conditions with ZnO as electron selective contact achieved an efficiency of 3.02%. We have demonstrated that by incorporating GO in ZnO matrix, low resistivity electron selective contacts, critical to improve the performance, can be achieved. We could achieve max efficiency of 4.52% with our completed devices for ZnO: GO composite. Impedance spectroscopy confirmed the decrease in series resistance and an increase in recombination resistance with inclusion of GO in ZnO matrix. Effect of temperature on completed devices was investigated by recording impedance spectra at 40 and 60 {sup o}C, providing indirect evidence of the performance of solar cells at elevated temperatures.

  17. Manufacturing Precise, Lightweight Paraboloidal Mirrors

    NASA Technical Reports Server (NTRS)

    Hermann, Frederick Thomas

    2006-01-01

    A process for fabricating a precise, diffraction- limited, ultra-lightweight, composite- material (matrix/fiber) paraboloidal telescope mirror has been devised. Unlike the traditional process of fabrication of heavier glass-based mirrors, this process involves a minimum of manual steps and subjective judgment. Instead, this process involves objectively controllable, repeatable steps; hence, this process is better suited for mass production. Other processes that have been investigated for fabrication of precise composite-material lightweight mirrors have resulted in print-through of fiber patterns onto reflecting surfaces, and have not provided adequate structural support for maintenance of stable, diffraction-limited surface figures. In contrast, this process does not result in print-through of the fiber pattern onto the reflecting surface and does provide a lightweight, rigid structure capable of maintaining a diffraction-limited surface figure in the face of changing temperature, humidity, and air pressure. The process consists mainly of the following steps: 1. A precise glass mandrel is fabricated by conventional optical grinding and polishing. 2. The mandrel is coated with a release agent and covered with layers of a carbon- fiber composite material. 3. The outer surface of the outer layer of the carbon-fiber composite material is coated with a surfactant chosen to provide for the proper flow of an epoxy resin to be applied subsequently. 4. The mandrel as thus covered is mounted on a temperature-controlled spin table. 5. The table is heated to a suitable temperature and spun at a suitable speed as the epoxy resin is poured onto the coated carbon-fiber composite material. 6. The surface figure of the optic is monitored and adjusted by use of traditional Ronchi, Focault, and interferometric optical measurement techniques while the speed of rotation and the temperature are adjusted to obtain the desired figure. The proper selection of surfactant, speed or rotation

  18. Development of superconducting YBa2Cu3O(x) wires with low resistance electrical contacts

    NASA Astrophysics Data System (ADS)

    Buoncristiani, A. M.; Byvik, C. E.; Caton, R.; Selim, R.; Lee, B. I.; Modi, V.; Sherrill, M.; Leigh, H. D.; Fain, C. C.; Lewis, G.

    Materials exhibiting superconductivity above liquid nitrogen temperatures (77 K) will enable new applications of this phenomena. One of the first commercial applications of this technology will be superconducting magnets for medical imaging. However, a large number of aerospace applications of the high temperature superconducting materials have also been identified. These include magnetic suspension and balance of models in wind tunnels and resistanceless leads to anemometers. The development of superconducting wires fabricated from the ceramic materials is critical for these applications. The progress in application of a patented fiber process developed by Clemson University for the fabrication of superconducting wires is reviewed. The effect of particle size and heat treatment on the quality of materials is discussed. Recent advances made at Christopher Newport College in the development of micro-ohm resistance electrical contacts which are capable of carrying the highest reported direct current to this material is presented.

  19. Development of superconducting YBa2Cu3O(x) wires with low resistance electrical contacts

    NASA Technical Reports Server (NTRS)

    Buoncristiani, A. M.; Byvik, C. E.; Caton, R.; Selim, R.; Lee, B. I.; Modi, V.; Sherrill, M.; Leigh, H. D.; Fain, C. C.; Lewis, G.

    1993-01-01

    Materials exhibiting superconductivity above liquid nitrogen temperatures (77 K) will enable new applications of this phenomena. One of the first commercial applications of this technology will be superconducting magnets for medical imaging. However, a large number of aerospace applications of the high temperature superconducting materials have also been identified. These include magnetic suspension and balance of models in wind tunnels and resistanceless leads to anemometers. The development of superconducting wires fabricated from the ceramic materials is critical for these applications. The progress in application of a patented fiber process developed by Clemson University for the fabrication of superconducting wires is reviewed. The effect of particle size and heat treatment on the quality of materials is discussed. Recent advances made at Christopher Newport College in the development of micro-ohm resistance electrical contacts which are capable of carrying the highest reported direct current to this material is presented.

  20. Polycrystalline silicon germanium for fabrication, release, and packaging of microelectromechanical systems

    NASA Astrophysics Data System (ADS)

    Heck, John Mccaslin

    Polycrystalline silicon germanium has recently proven to be a compelling alternative to polysilicon for micromachining. Low temperature fabrication of micromechanical structures is possible, which enables their modular integration with conventional electronics. The deposition and crystallization temperatures are significantly lower than for polysilicon, and low-stress, low-resistivity structural films can be achieved with little or no annealing. Poly-Ge can be used as a hydrogen peroxide-soluble sacrificial layer, so a wide variety of microfabrication materials can withstand the release etch. Several aspects of our research on poly-SiGe micromachining are presented in this dissertation. First, a "handbook" of poly-SiGe processing for MEMS is given, along with an overview of the advantages of this material system. An extensive study of the etching of poly-Ge sacrificial layers by heated hydrogen peroxide is presented. The dissolution of poly-Ge is limited by the dissolution of a GeO2 surface layer, and the activation energy was determined to be 9.3 kcal/mol. The etch rate was determined to be roughly 0.5 mum/min at 90°C, which is 4--6 orders of magnitude faster than structural films containing 20--60% Ge. The reaction was determined to be limited partly by the reaction rate and partly by diffusion, and diffusion limits on the order of 1 mm were observed. The fabrication of robust, high-aspect-ratio poly-SiGe structures by a thin film micromolding process (hexsil) is presented. Due to the excellent conformality of poly-Ge compared to SiO2 sacrificial layers, precise replication of the mold wafer was achieved. A gimbal/microactuator fabricated in this process enabled a critical dimension to be reduced from 7 to 4.5 mum when compared to a device made in a conventional process. Poly-SiGe hexsil was also used to fabricate micromachined caps for a precision MEMS packaging technology. In this process, the hexsil caps were fabricated on a mold wafer and transferred to a

  1. Precise Countersinking Tool

    NASA Technical Reports Server (NTRS)

    Jenkins, Eric S.; Smith, William N.

    1992-01-01

    Tool countersinks holes precisely with only portable drill; does not require costly machine tool. Replaceable pilot stub aligns axis of tool with centerline of hole. Ensures precise cut even with imprecise drill. Designed for relatively low cutting speeds.

  2. Precision agricultural systems

    USDA-ARS?s Scientific Manuscript database

    Precision agriculture is a new farming practice that has been developing since late 1980s. It has been variously referred to as precision farming, prescription farming, site-specific crop management, to name but a few. There are numerous definitions for precision agriculture, but the central concept...

  3. Extended precision software packages

    NASA Technical Reports Server (NTRS)

    Phillips, E. J.

    1972-01-01

    A description of three extended precision packages is presented along with three small conversion subroutines which can be used in conjunction with the extended precision packages. These extended packages represent software packages written in FORTRAN 4. They contain normalized or unnormalized floating point arithmetic with symmetric rounding and arbitrary mantissa lengths, and normalized floating point interval arithmetic with appropriate rounding. The purpose of an extended precision package is to enable the user to use and manipulate numbers with large decimal places as well as those with small decimal places where precision beyond double precision is required.

  4. Minority-carrier mobility anomalies in low-resistivity silicon solar cells

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Delombard, R.

    1986-01-01

    Measurement of the minority-carrier mobility in the base region of a high-voltage metal-insulator-N-P solar cell (Green et al., 1984), as well as in other 0.1-ohm cm cells, provides direct proof that the high voltages measured for that cell are due not only to improved emitter characteristics but to an improved base region as well. The base characteristics are shown to be quite sensitive to the effects of diffusion-induced lattice stress originating in the emitter. The implications of these findings for the fabrication of high-efficiency cells are discussed.

  5. Precision performance lamp technology

    NASA Astrophysics Data System (ADS)

    Bell, Dean A.; Kiesa, James E.; Dean, Raymond A.

    1997-09-01

    A principal function of a lamp is to produce light output with designated spectra, intensity, and/or geometric radiation patterns. The function of a precision performance lamp is to go beyond these parameters and into the precision repeatability of performance. All lamps are not equal. There are a variety of incandescent lamps, from the vacuum incandescent indictor lamp to the precision lamp of a blood analyzer. In the past the definition of a precision lamp was described in terms of wattage, light center length (LCL), filament position, and/or spot alignment. This paper presents a new view of precision lamps through the discussion of a new segment of lamp design, which we term precision performance lamps. The definition of precision performance lamps will include (must include) the factors of a precision lamp. But what makes a precision lamp a precision performance lamp is the manner in which the design factors of amperage, mscp (mean spherical candlepower), efficacy (lumens/watt), life, not considered individually but rather considered collectively. There is a statistical bias in a precision performance lamp for each of these factors; taken individually and as a whole. When properly considered the results can be dramatic to the system design engineer, system production manage and the system end-user. It can be shown that for the lamp user, the use of precision performance lamps can translate to: (1) ease of system design, (2) simplification of electronics, (3) superior signal to noise ratios, (4) higher manufacturing yields, (5) lower system costs, (6) better product performance. The factors mentioned above are described along with their interdependent relationships. It is statistically shown how the benefits listed above are achievable. Examples are provided to illustrate how proper attention to precision performance lamp characteristics actually aid in system product design and manufacturing to build and market more, market acceptable product products in the

  6. Advanced irrigation engineering: Precision and Precise

    USDA-ARS?s Scientific Manuscript database

    Irrigation advances in precision irrigation (PI) or site-specific irrigation (SSI) have been considerable in research; however commercialization lags. A primary necessity for it is variability in soil texture that affects soil water holding capacity and crop yield. Basically, SSI/PI uses variable ra...

  7. Turning an organic semiconductor into a low-resistance material by ion implantation.

    PubMed

    Fraboni, Beatrice; Scidà, Alessandra; Cosseddu, Piero; Wang, Yongqiang; Nastasi, Michael; Milita, Silvia; Bonfiglio, Annalisa

    2015-12-01

    We report on the effects of low energy ion implantation on thin films of pentacene, carried out to investigate the efficacy of this process in the fabrication of organic electronic devices. Two different ions, Ne and N, have been implanted and compared, to assess the effects of different reactivity within the hydrocarbon matrix. Strong modification of the electrical conductivity, stable in time, is observed following ion implantation. This effect is significantly larger for N implants (up to six orders of magnitude), which are shown to introduce stable charged species within the hydrocarbon matrix, not only damage as is the case for Ne implants. Fully operational pentacene thin film transistors have also been implanted and we show how a controlled N ion implantation process can induce stable modifications in the threshold voltage, without affecting the device performance.

  8. Turning an organic semiconductor into a low-resistance material by ion implantation

    PubMed Central

    Fraboni, Beatrice; Scidà, Alessandra; Cosseddu, Piero; Wang, Yongqiang; Nastasi, Michael; Milita, Silvia; Bonfiglio, Annalisa

    2015-01-01

    We report on the effects of low energy ion implantation on thin films of pentacene, carried out to investigate the efficacy of this process in the fabrication of organic electronic devices. Two different ions, Ne and N, have been implanted and compared, to assess the effects of different reactivity within the hydrocarbon matrix. Strong modification of the electrical conductivity, stable in time, is observed following ion implantation. This effect is significantly larger for N implants (up to six orders of magnitude), which are shown to introduce stable charged species within the hydrocarbon matrix, not only damage as is the case for Ne implants. Fully operational pentacene thin film transistors have also been implanted and we show how a controlled N ion implantation process can induce stable modifications in the threshold voltage, without affecting the device performance. PMID:27877850

  9. Precision Attachments for Aesthetics and Function: A Case Report

    PubMed Central

    Shetty, Nitin Bhaskar; Shetty, Sanyuktha; E, Nagaraj; Shetty, Omkar; D’souza, Raina

    2014-01-01

    Successful restoration of the dentition requires plenty of contemporary and conventional treatment techniques and planning and attachment retained partial dentures are one such kind of treatment modality in prosthodontics. Limited space for extracoronal attachments is a serious gap in the design and the fabrication of a precision attachment Removable Partial Denture (RPD). A custom semi-precision attachment with a partial denture offers strength and improved aesthetics in cases with minimal space. This article presents a method of fabrication of semi-precision attachment to eliminate metal display and enhance aestheticity. PMID:24596792

  10. [Precision and personalized medicine].

    PubMed

    Sipka, Sándor

    2016-10-01

    The author describes the concept of "personalized medicine" and the newly introduced "precision medicine". "Precision medicine" applies the terms of "phenotype", "endotype" and "biomarker" in order to characterize more precisely the various diseases. Using "biomarkers" the homogeneous type of a disease (a "phenotype") can be divided into subgroups called "endotypes" requiring different forms of treatment and financing. The good results of "precision medicine" have become especially apparent in relation with allergic and autoimmune diseases. The application of this new way of thinking is going to be necessary in Hungary, too, in the near future for participants, controllers and financing boards of healthcare. Orv. Hetil., 2016, 157(44), 1739-1741.

  11. Precision positioning device

    SciTech Connect

    McInroy, John E.

    2005-01-18

    A precision positioning device is provided. The precision positioning device comprises a precision measuring/vibration isolation mechanism. A first plate is provided with the precision measuring mean secured to the first plate. A second plate is secured to the first plate. A third plate is secured to the second plate with the first plate being positioned between the second plate and the third plate. A fourth plate is secured to the third plate with the second plate being positioned between the third plate and the fourth plate. An adjusting mechanism for adjusting the position of the first plate, the second plate, the third plate, and the fourth plate relative to each other.

  12. Atomically Precise Surface Engineering for Producing Imagers

    NASA Technical Reports Server (NTRS)

    Greer, Frank (Inventor); Jones, Todd J. (Inventor); Nikzad, Shouleh (Inventor); Hoenk, Michael E. (Inventor)

    2015-01-01

    High-quality surface coatings, and techniques combining the atomic precision of molecular beam epitaxy and atomic layer deposition, to fabricate such high-quality surface coatings are provided. The coatings made in accordance with the techniques set forth by the invention are shown to be capable of forming silicon CCD detectors that demonstrate world record detector quantum efficiency (>50%) in the near and far ultraviolet (155 nm-300 nm). The surface engineering approaches used demonstrate the robustness of detector performance that is obtained by achieving atomic level precision at all steps in the coating fabrication process. As proof of concept, the characterization, materials, and exemplary devices produced are presented along with a comparison to other approaches.

  13. Advanced composite materials for precision segmented reflectors

    NASA Technical Reports Server (NTRS)

    Stein, Bland A.; Bowles, David E.

    1988-01-01

    The objective in the NASA Precision Segmented Reflector (PSR) project is to develop new composite material concepts for highly stable and durable reflectors with precision surfaces. The project focuses on alternate material concepts such as the development of new low coefficient of thermal expansion resins as matrices for graphite fiber reinforced composites, quartz fiber reinforced epoxies, and graphite reinforced glass. Low residual stress fabrication methods will be developed. When coupon specimens of these new material concepts have demonstrated the required surface accuracies and resistance to thermal distortion and microcracking, reflector panels will be fabricated and tested in simulated space environments. An important part of the program is the analytical modeling of environmental stability of these new composite materials concepts through constitutive equation development, modeling of microdamage in the composite matrix, and prediction of long term stability (including viscoelasticity). These analyses include both closed form and finite element solutions at the micro and macro levels.

  14. Precision antenna reflector structures

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1985-01-01

    The assembly of the Large Precise Reflector Infrared Telescope is detailed. Also given are the specifications for the Aft Cargo Carrier and the Large Precision Reflector structure. Packaging concepts and options, stowage depth and support truss geometry are also considered. An example of a construction scenario is given.

  15. Precision Optics Curriculum.

    ERIC Educational Resources Information Center

    Reid, Robert L.; And Others

    This guide outlines the competency-based, two-year precision optics curriculum that the American Precision Optics Manufacturers Association has proposed to fill the void that it suggests will soon exist as many of the master opticians currently employed retire. The model, which closely resembles the old European apprenticeship model, calls for 300…

  16. Precision Optics Curriculum.

    ERIC Educational Resources Information Center

    Reid, Robert L.; And Others

    This guide outlines the competency-based, two-year precision optics curriculum that the American Precision Optics Manufacturers Association has proposed to fill the void that it suggests will soon exist as many of the master opticians currently employed retire. The model, which closely resembles the old European apprenticeship model, calls for 300…

  17. Fabrication of precision glass shells by joining glass rods

    DOEpatents

    Gac, Frank D.; Blake, Rodger D.; Day, Delbert E.; Haggerty, John S.

    1988-01-01

    A method for making uniform spherical shells. The present invention allows niform hollow spheres to be made by first making a void in a body of material. The material is heated so that the viscosity is sufficiently low so that the surface tension will transform the void into a bubble. The bubble is allowed to rise in the body until it is spherical. The excess material is removed from around the void to form a spherical shell with a uniform outside diameter.

  18. The structure of a magnetic-field front propagating non-diffusively in low-resistivity multi-species plasma

    NASA Astrophysics Data System (ADS)

    Rubinstein, B.; Doron, R.; Maron, Y.; Fruchtman, A.; Mehlhorn, T. A.

    2016-04-01

    We report on the first experimental verification of the traveling-wave-like picture of a magnetic-field and an associated electric potential hill propagating non-diffusively in low resistivity plasma. High spatial resolution spectroscopic method, developed here, allowed for obtaining the detailed shape of the propagating magnetic-field front. The measurements demonstrated that the ion separation, previously claimed, results from the reflection of the higher charge-to-mass ratio ions from the propagating potential hill and from climbing the hill by the lower charge-to-mass ratio ions. This ion dynamics is found to be consistent with the observed electron density evolution.

  19. The structure of a magnetic-field front propagating non-diffusively in low-resistivity multi-species plasma

    SciTech Connect

    Rubinstein, B.; Doron, R. Maron, Y.; Fruchtman, A.; Mehlhorn, T. A.

    2016-04-15

    We report on the first experimental verification of the traveling-wave-like picture of a magnetic-field and an associated electric potential hill propagating non-diffusively in low resistivity plasma. High spatial resolution spectroscopic method, developed here, allowed for obtaining the detailed shape of the propagating magnetic-field front. The measurements demonstrated that the ion separation, previously claimed, results from the reflection of the higher charge-to-mass ratio ions from the propagating potential hill and from climbing the hill by the lower charge-to-mass ratio ions. This ion dynamics is found to be consistent with the observed electron density evolution.

  20. Room temperature gas-solid reaction of titanium on glass surfaces forming a very low resistivity layer

    NASA Astrophysics Data System (ADS)

    Solís, Hugo; Clark, Neville; Azofeifa, Daniel; Avendano, E.

    2016-09-01

    Titanium films were deposited on quartz, glass, polyamide and PET substrates in a high vacuum system at room temperature and their electrical resistance monitored in vacuo as a function of thickness. These measurements indicate that a low electrical resistance layer is formed in a gas-solid reaction during the condensation of the initial layers of Ti on glass and quartz substrates. Layers begin to show relative low electrical resistance at around 21 nm for glass and 9nm for quartz. Samples deposited on polyamide and PET do not show this low resistance feature.

  1. Triaxial Fabrics

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Gentax Corporation's triaxal fabrics are woven from three separate yarn sets whose intersections form equilateral triangles. This type of weave, derived from space shuttle pressure suits, assures practically equal strength in every direction; has essentially no bias, or weak dimension offering greater resistance to tear and shear along with significant weight reduction. Applications of the Triax line include inflatable equipment, life vests, aircraft evacuation slides, helicopter flotation devices, tension structures, safety clothing and sailcloth for boats. Ability to accept compound curvatures with no distortion of the weave configuration makes it useful in manufacturing molded composites.

  2. Evaluation of Cross-Hole Seismic Tomography for Imaging Low Resistance Intervals and Associated Carbonate Sediments in Coastal Plain Sequences on the Savannah River Site, South Carolina

    SciTech Connect

    Cumbest, R. J.

    1999-01-05

    The objectives of the pilot study were to investigate the limitations of the technique for imaging the presence, extent, and boundaries of the low-resistance intervals and associated carbonate sediments.

  3. Precision volume measurement system.

    SciTech Connect

    Fischer, Erin E.; Shugard, Andrew D.

    2004-11-01

    A new precision volume measurement system based on a Kansas City Plant (KCP) design was built to support the volume measurement needs of the Gas Transfer Systems (GTS) department at Sandia National Labs (SNL) in California. An engineering study was undertaken to verify or refute KCP's claims of 0.5% accuracy. The study assesses the accuracy and precision of the system. The system uses the ideal gas law and precise pressure measurements (of low-pressure helium) in a temperature and computer controlled environment to ratio a known volume to an unknown volume.

  4. Dispensing of high concentration Ag nano-particles ink for ultra-low resistivity paper-based writing electronics

    NASA Astrophysics Data System (ADS)

    Wang, Fuliang; Mao, Peng; He, Hu

    2016-02-01

    Paper-based writing electronics has received a lot of interest recently due to its potential applications in flexible electronics. To obtain ultra-low resistivity paper-based writing electronics, we developed a kind of ink with high concentration of Ag Nano-particles (up to 80 wt%), as well as a related dispensing writing system consisting an air compressor machine and a dispenser. Additionally, we also demonstrated the writability and practical application of our proposed ink and writing system. Based on the study on the effect of sintering time and pressure, we found the optimal sintering time and pressure to obtain high quality Ag NPs wires. The electrical conductivity of nano-silver paper-based electronics has been tested using the calculated resistivity. After hot-pressure sintering at 120 °C, 25 MPa pressure for 20 minutes, the resistivity of silver NPs conductive tracks was 3.92 × 10-8 (Ωm), only 2.45 times of bulk silver. The mechanical flexibility of nano-silver paper-based electronics also has been tested. After 1000 bending cycles, the resistivity slightly increased from the initial 4.01 × 10-8 to 5.08 × 10-8 (Ωm). With this proposed ink preparation and writing system, a kind of paper-based writing electronics with ultra-low resistivity and good mechanical flexibility was achieved.

  5. Dispensing of high concentration Ag nano-particles ink for ultra-low resistivity paper-based writing electronics.

    PubMed

    Wang, Fuliang; Mao, Peng; He, Hu

    2016-02-17

    Paper-based writing electronics has received a lot of interest recently due to its potential applications in flexible electronics. To obtain ultra-low resistivity paper-based writing electronics, we developed a kind of ink with high concentration of Ag Nano-particles (up to 80 wt%), as well as a related dispensing writing system consisting an air compressor machine and a dispenser. Additionally, we also demonstrated the writability and practical application of our proposed ink and writing system. Based on the study on the effect of sintering time and pressure, we found the optimal sintering time and pressure to obtain high quality Ag NPs wires. The electrical conductivity of nano-silver paper-based electronics has been tested using the calculated resistivity. After hot-pressure sintering at 120 °C, 25 MPa pressure for 20 minutes, the resistivity of silver NPs conductive tracks was 3.92 × 10(-8) (Ωm), only 2.45 times of bulk silver. The mechanical flexibility of nano-silver paper-based electronics also has been tested. After 1000 bending cycles, the resistivity slightly increased from the initial 4.01 × 10(-8) to 5.08 × 10(-8) (Ωm). With this proposed ink preparation and writing system, a kind of paper-based writing electronics with ultra-low resistivity and good mechanical flexibility was achieved.

  6. Low-Resistance Dual-Purpose Air Filter Releasing Negative Ions and Effectively Capturing PM2.5.

    PubMed

    Zhao, Xinglei; Li, Yuyao; Hua, Ting; Jiang, Pan; Yin, Xia; Yu, Jianyong; Ding, Bin

    2017-04-05

    The fatal danger of pollution due to particulate matter (PM) calls for both high-efficiency and low-resistance air purification materials, which also provide healthcare. This is however still a challenge. Herein, a low-resistance air filter capable of releasing negative ions (NIs) and efficiently capturing PM2.5 was prepared by electrospinning polyvinylidene fluoride (PVDF) fibers doped with negative ions powder (NIPs). The air-resistance of fibrous membranes decreased from 9.5 to 6 Pa (decrease of 36%) on decreasing the average fiber diameter from 1.16 to 0.41 μm. Moreover, the lower rising rate of air-resistance with reduction in pore size, for fibrous membranes with thinner fiber diameter was verified. In addition, a single PVDF/NIPs fiber was provided with strong surface potentials, due to high fluorine electronegativity, and tested using atomic force microscopy. This strong surface potential resulted in higher releasing amounts of NIs (RANIs). Interestingly, reduction of fiber diameter favored the alleviation of the shielding effects on electric field around fibers and promoted the RANIs from 798 to 1711 ions cc(-1). Moreover, by regulating the doping contents of NIPs, the RANIs increased from 1711 to 2818 ions cc(-1). The resultant fibrous membranes showed low air resistance of 40.5 Pa. Field-tests conducted in Shanghai showed stable PM2.5 purification efficiency of 99.99% at high RANIs, in the event of haze.

  7. Nanoimprint lithography for nanodevice fabrication

    NASA Astrophysics Data System (ADS)

    Barcelo, Steven; Li, Zhiyong

    2016-09-01

    Nanoimprint lithography (NIL) is a compelling technique for low cost nanoscale device fabrication. The precise and repeatable replication of nanoscale patterns from a single high resolution patterning step makes the NIL technique much more versatile than other expensive techniques such as e-beam or even helium ion beam lithography. Furthermore, the use of mechanical deformation during the NIL process enables grayscale lithography with only a single patterning step, not achievable with any other conventional lithography techniques. These strengths enable the fabrication of unique nanoscale devices by NIL for a variety of applications including optics, plasmonics and even biotechnology. Recent advances in throughput and yield in NIL processes demonstrate the potential of being adopted for mainstream semiconductor device fabrication as well.

  8. Nanoimprint lithography for nanodevice fabrication.

    PubMed

    Barcelo, Steven; Li, Zhiyong

    2016-01-01

    Nanoimprint lithography (NIL) is a compelling technique for low cost nanoscale device fabrication. The precise and repeatable replication of nanoscale patterns from a single high resolution patterning step makes the NIL technique much more versatile than other expensive techniques such as e-beam or even helium ion beam lithography. Furthermore, the use of mechanical deformation during the NIL process enables grayscale lithography with only a single patterning step, not achievable with any other conventional lithography techniques. These strengths enable the fabrication of unique nanoscale devices by NIL for a variety of applications including optics, plasmonics and even biotechnology. Recent advances in throughput and yield in NIL processes demonstrate the potential of being adopted for mainstream semiconductor device fabrication as well.

  9. Precision Measurement in Biology

    NASA Astrophysics Data System (ADS)

    Quake, Stephen

    Is biology a quantitative science like physics? I will discuss the role of precision measurement in both physics and biology, and argue that in fact both fields can be tied together by the use and consequences of precision measurement. The elementary quanta of biology are twofold: the macromolecule and the cell. Cells are the fundamental unit of life, and macromolecules are the fundamental elements of the cell. I will describe how precision measurements have been used to explore the basic properties of these quanta, and more generally how the quest for higher precision almost inevitably leads to the development of new technologies, which in turn catalyze further scientific discovery. In the 21st century, there are no remaining experimental barriers to biology becoming a truly quantitative and mathematical science.

  10. Precision liquid level sensor

    DOEpatents

    Field, M.E.; Sullivan, W.H.

    A precision liquid level sensor utilizes a balanced bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge.

  11. Optimetrics for Precise Navigation

    NASA Technical Reports Server (NTRS)

    Yang, Guangning; Heckler, Gregory; Gramling, Cheryl

    2017-01-01

    Optimetrics for Precise Navigation will be implemented on existing optical communication links. The ranging and Doppler measurements are conducted over communication data frame and clock. The measurement accuracy is two orders of magnitude better than TDRSS. It also has other advantages of: The high optical carrier frequency enables: (1) Immunity from ionosphere and interplanetary Plasma noise floor, which is a performance limitation for RF tracking; and (2) High antenna gain reduces terminal size and volume, enables high precision tracking in Cubesat, and in deep space smallsat. High Optical Pointing Precision provides: (a) spacecraft orientation, (b) Minimal additional hardware to implement Precise Optimetrics over optical comm link; and (c) Continuous optical carrier phase measurement will enable the system presented here to accept future optical frequency standard with much higher clock accuracy.

  12. Precision digital control systems

    NASA Astrophysics Data System (ADS)

    Vyskub, V. G.; Rozov, B. S.; Savelev, V. I.

    This book is concerned with the characteristics of digital control systems of great accuracy. A classification of such systems is considered along with aspects of stabilization, programmable control applications, digital tracking systems and servomechanisms, and precision systems for the control of a scanning laser beam. Other topics explored are related to systems of proportional control, linear devices and methods for increasing precision, approaches for further decreasing the response time in the case of high-speed operation, possibilities for the implementation of a logical control law, and methods for the study of precision digital control systems. A description is presented of precision automatic control systems which make use of electronic computers, taking into account the existing possibilities for an employment of computers in automatic control systems, approaches and studies required for including a computer in such control systems, and an analysis of the structure of automatic control systems with computers. Attention is also given to functional blocks in the considered systems.

  13. Precision displacement reference system

    DOEpatents

    Bieg, Lothar F.; Dubois, Robert R.; Strother, Jerry D.

    2000-02-22

    A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

  14. Precision medicine in cardiology.

    PubMed

    Antman, Elliott M; Loscalzo, Joseph

    2016-10-01

    The cardiovascular research and clinical communities are ideally positioned to address the epidemic of noncommunicable causes of death, as well as advance our understanding of human health and disease, through the development and implementation of precision medicine. New tools will be needed for describing the cardiovascular health status of individuals and populations, including 'omic' data, exposome and social determinants of health, the microbiome, behaviours and motivations, patient-generated data, and the array of data in electronic medical records. Cardiovascular specialists can build on their experience and use precision medicine to facilitate discovery science and improve the efficiency of clinical research, with the goal of providing more precise information to improve the health of individuals and populations. Overcoming the barriers to implementing precision medicine will require addressing a range of technical and sociopolitical issues. Health care under precision medicine will become a more integrated, dynamic system, in which patients are no longer a passive entity on whom measurements are made, but instead are central stakeholders who contribute data and participate actively in shared decision-making. Many traditionally defined diseases have common mechanisms; therefore, elimination of a siloed approach to medicine will ultimately pave the path to the creation of a universal precision medicine environment.

  15. Estimating sparse precision matrices

    NASA Astrophysics Data System (ADS)

    Padmanabhan, Nikhil; White, Martin; Zhou, Harrison H.; O'Connell, Ross

    2016-08-01

    We apply a method recently introduced to the statistical literature to directly estimate the precision matrix from an ensemble of samples drawn from a corresponding Gaussian distribution. Motivated by the observation that cosmological precision matrices are often approximately sparse, the method allows one to exploit this sparsity of the precision matrix to more quickly converge to an asymptotic 1/sqrt{N_sim} rate while simultaneously providing an error model for all of the terms. Such an estimate can be used as the starting point for further regularization efforts which can improve upon the 1/sqrt{N_sim} limit above, and incorporating such additional steps is straightforward within this framework. We demonstrate the technique with toy models and with an example motivated by large-scale structure two-point analysis, showing significant improvements in the rate of convergence. For the large-scale structure example, we find errors on the precision matrix which are factors of 5 smaller than for the sample precision matrix for thousands of simulations or, alternatively, convergence to the same error level with more than an order of magnitude fewer simulations.

  16. Low resistance nonalloyed Ni/Au Ohmic contacts to p-GaN irradiated by KrF excimer laser

    SciTech Connect

    Oh, Min-Suk; Hwang, Dae-Kue; Lim, Jae-Hong; Kang, Chang-Goo; Park, Seong-Ju

    2006-07-24

    A specific contact resistance of 8.9x10{sup -5} {omega} cm{sup 2} was obtained for a Ni/Au Ohmic layer on the KrF laser-irradiated p-GaN. It was found that laser irradiation increases the hole concentration from 4.1x10{sup 17} to 9.7x10{sup 17} cm{sup -3} by removing hydrogen atoms from p-GaN layer. The native oxide was also removed as evidenced by the Ga 2p peak shift and the decrease in the intensity of O 1s peak in the x-ray photoelectron spectra. The formation of a low resistance is attributed to the increase in the hole concentration and the removal of native oxide from p-GaN by laser irradiation.

  17. Origins of low resistivity and Ge donor level in Ge ion-implanted ZnO bulk single crystals

    SciTech Connect

    Kamioka, K.; Oga, T.; Izawa, Y.; Kuriyama, K.; Kushida, K.

    2013-12-04

    The energy level of Ge in Ge-ion implanted ZnO single crystals is studied by Hall-effect and photoluminescence (PL) methods. The variations in resistivity from ∼10{sup 3} Ωcm for un-implanted samples to ∼10{sup −2} Ωcm for as-implanted ones are observed. The resistivity is further decreased to ∼10{sup −3} Ωcm by annealing. The origins of the low resistivity are attributed to both the zinc interstitial (Zn{sub i}) related defects and the electrical activated Ge donor. An activation energy of Ge donors estimated from the temperature dependence of carrier concentration is 102 meV. In PL studies, the new peak at 372 nm (3.33 eV) related to the Ge donor is observed in 1000 °C annealed samples.

  18. Micro-structural characterization of low resistive metallic Ni germanide growth on annealing of Ni-Ge multilayer

    SciTech Connect

    Swain, Mitali Singh, Surendra Bhattacharya, Debarati; Basu, Saibal; Singh, Ajay; Prajapat, C. L.; Tokas, R.B.

    2015-07-15

    Nickel-Germanides are an important class of metal semiconductor alloys because of their suitability in microelectronics applications. Here we report successful formation and detailed characterization of NiGe metallic alloy phase at the interfaces of a Ni-Ge multilayer on controlled annealing at relatively low temperature ∼ 250 °C. Using x-ray and polarized neutron reflectometry, we could estimate the width of the interfacial alloys formed with nanometer resolution and found the alloy stoichiometry to be equiatomic NiGe, a desirable low-resistance interconnect. We found significant drop in resistance (∼ 50%) on annealing the Ni-Ge multilayer suggesting metallic nature of alloy phase at the interfaces. Further we estimated the resistivity of the alloy phase to be ∼ 59μΩ cm.

  19. Study program to improve the open-circuit voltage of low resistivity single crystal silicon solar cells

    NASA Technical Reports Server (NTRS)

    Minnucci, J. A.; Matthei, K. W.

    1980-01-01

    The results of a 14 month program to improve the open circuit voltage of low resistivity silicon solar cells are described. The approach was based on ion implantation in 0.1- to 10.0-ohm-cm float-zone silicon. As a result of the contract effort, open circuit voltages as high as 645 mV (AMO 25 C) were attained by high dose phosphorus implantation followed by furnace annealing and simultaneous SiO2 growth. One key element was to investigate the effects of bandgap narrowing caused by high doping concentrations in the junction layer. Considerable effort was applied to optimization of implant parameters, selection of furnace annealing techniques, and utilization of pulsed electron beam annealing to minimize thermal process-induced defects in the completed solar cells.

  20. Solar cells on low-resistivity boron-doped Czochralski-grown silicon with stabilized efficiencies of 20%

    NASA Astrophysics Data System (ADS)

    Lim, Bianca; Hermann, Sonja; Bothe, Karsten; Schmidt, Jan; Brendel, Rolf

    2008-10-01

    Recently, it was shown that the boron-oxygen complex responsible for the light-induced lifetime degradation in oxygen-rich boron-doped silicon can be permanently deactivated by illumination at elevated temperatures. Since the degradation is particularly harmful in low-resistivity Czochralski silicon (Cz-Si), we apply the deactivation procedure to a high-efficiency rear interdigitated single evaporation emitter wrap-through solar cell made on 1.4Ωcm B-doped Cz-Si. The energy conversion efficiency is thereby increased by more than 1% absolute compared to the degraded state to 20.3% on a designated area of 92cm2 and is furthermore shown to be stable under illumination at room temperature.

  1. On the luminescence of freshly introduced a-screw dislocations in low-resistance GaN

    SciTech Connect

    Medvedev, O. S. Vyvenko, O. F.; Bondarenko, A. S.

    2015-09-15

    Using scanning electron microscopy in the cathodoluminescence mode, it is shown that straight segments of a-screw dislocations introduced by plastic deformation at room temperature into unintentionally doped low-resistance gallium nitride luminesce in the spectral range 3.1–3.2 eV at 70 K. The spectral composition of dislocation luminescence shows a fine doublet structure with a component width of ∼15 meV and splitting of ∼30 meV, accompanied by LO-phonon replicas. Luminescent screw dislocations move upon exposure to an electron beam and at low temperatures, but retain immobility for a long time without external excitation. Optical transitions involving the quantum-well states of a stacking fault in a split-dislocation core are considered to be the most probable mechanism of the observed phenomenon.

  2. Low resistivity, low contrast pays: Part II-comparison of examples from Southeast Asia and the Gulf of Mexico

    SciTech Connect

    Kulha, J.T.; Sneider, R.M.

    1994-07-01

    The Gulf of Mexico Basin (GOM) is the world's leading oil and gas producer from low resistivity, low contrast (LRLC) clastic intervals. Many GOM fields have had production from LRLC pays for more than 15 years and some for over 40 yrs. LRLC pay zones are being recognized more frequently now in other basins in the world, including southeast Asia. LRLC pays in southeast Asia have many similarities and some differences with the LRLC producing zones in the Gulf of Mexico Basin. The depositional environments containing LRLC pays in southeast Asia are (1) major regional and local marine transgressive sands, (2) deep-water sands, including levee-channel complexes, (3) deltaic channel and bar-front sands, and (4) shingled turbidites. LRLC pays in marine transgressive sands are more abundant in southeast Asia.

  3. Precision gap particle separator

    DOEpatents

    Benett, William J.; Miles, Robin; Jones, II., Leslie M.; Stockton, Cheryl

    2004-06-08

    A system for separating particles entrained in a fluid includes a base with a first channel and a second channel. A precision gap connects the first channel and the second channel. The precision gap is of a size that allows small particles to pass from the first channel into the second channel and prevents large particles from the first channel into the second channel. A cover is positioned over the base unit, the first channel, the precision gap, and the second channel. An port directs the fluid containing the entrained particles into the first channel. An output port directs the large particles out of the first channel. A port connected to the second channel directs the small particles out of the second channel.

  4. Precision Muonium Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jungmann, Klaus P.

    2016-09-01

    The muonium atom is the purely leptonic bound state of a positive muon and an electron. It has a lifetime of 2.2 µs. The absence of any known internal structure provides for precision experiments to test fundamental physics theories and to determine accurate values of fundamental constants. In particular ground state hyperfine structure transitions can be measured by microwave spectroscopy to deliver the muon magnetic moment. The frequency of the 1s-2s transition in the hydrogen-like atom can be determined with laser spectroscopy to obtain the muon mass. With such measurements fundamental physical interactions, in particular quantum electrodynamics, can also be tested at highest precision. The results are important input parameters for experiments on the muon magnetic anomaly. The simplicity of the atom enables further precise experiments, such as a search for muonium-antimuonium conversion for testing charged lepton number conservation and searches for possible antigravity of muons and dark matter.

  5. Developing Precision Stroke Imaging

    PubMed Central

    Feldmann, Edward; Liebeskind, David S.

    2014-01-01

    Stroke experts stand at the cusp of a unique opportunity to advance the care of patients with cerebrovascular disorders across the globe through improved imaging approaches. NIH initiatives including the Stroke Progress Review Group promotion of imaging in stroke research and the newly established NINDS Stroke Trials network converge with the rapidly evolving concept of precision medicine. Precision stroke imaging portends the coming shift to individualized approaches to cerebrovascular disorders where big data may be leveraged to identify and manage stroke risk with specific treatments utilizing an improved neuroimaging infrastructure, data collection, and analysis. We outline key aspects of the stroke imaging field where precision medicine may rapidly transform the care of stroke patients in the next few years. PMID:24715885

  6. How Physics Got Precise

    SciTech Connect

    Kleppner, Daniel

    2005-01-19

    Although the ancients knew the length of the year to about ten parts per million, it was not until the end of the 19th century that precision measurements came to play a defining role in physics. Eventually such measurements made it possible to replace human-made artifacts for the standards of length and time with natural standards. For a new generation of atomic clocks, time keeping could be so precise that the effects of the local gravitational potentials on the clock rates would be important. This would force us to re-introduce an artifact into the definition of the second - the location of the primary clock. I will describe some of the events in the history of precision measurements that have led us to this pleasing conundrum, and some of the unexpected uses of atomic clocks today.

  7. Vernier scales and other early devices for precise measurement

    NASA Astrophysics Data System (ADS)

    Kwan, Alistair

    2011-04-01

    Vernier scales have been extensively used since the 17th century. They replaced the Nonius scale, a unpopular device due to difficulty in its fabrication and use, and they coexisted alongside other types of scales that increased measurement precision and accuracy in complementary ways. I suggest that the success of Vernier and diagonal scales is due not only to simplicity of fabrication, but also to their exploitation of visual hyperacuities.

  8. Dispensing of high concentration Ag nano-particles ink for ultra-low resistivity paper-based writing electronics

    PubMed Central

    Wang, Fuliang; Mao, Peng; He, Hu

    2016-01-01

    Paper-based writing electronics has received a lot of interest recently due to its potential applications in flexible electronics. To obtain ultra-low resistivity paper-based writing electronics, we developed a kind of ink with high concentration of Ag Nano-particles (up to 80 wt%), as well as a related dispensing writing system consisting an air compressor machine and a dispenser. Additionally, we also demonstrated the writability and practical application of our proposed ink and writing system. Based on the study on the effect of sintering time and pressure, we found the optimal sintering time and pressure to obtain high quality Ag NPs wires. The electrical conductivity of nano-silver paper-based electronics has been tested using the calculated resistivity. After hot-pressure sintering at 120 °C, 25 MPa pressure for 20 minutes, the resistivity of silver NPs conductive tracks was 3.92 × 10−8 (Ωm), only 2.45 times of bulk silver. The mechanical flexibility of nano-silver paper-based electronics also has been tested. After 1000 bending cycles, the resistivity slightly increased from the initial 4.01 × 10−8 to 5.08 × 10−8 (Ωm). With this proposed ink preparation and writing system, a kind of paper-based writing electronics with ultra-low resistivity and good mechanical flexibility was achieved. PMID:26883558

  9. Low-resistivity bulk silicon prepared by hot-pressing boron- and phosphorus-hyperdoped silicon nanocrystals

    SciTech Connect

    Luan, Qingbin; Ni, Zhenyi; Zhu, Tiejun; Yang, Deren; Pi, Xiaodong; Koura, Setsuko

    2014-12-15

    Technologically important low-resistivity bulk Si has been usually produced by the traditional Czochralski growth method. We now explore a novel method to obtain low-resistivity bulk Si by hot-pressing B- and P-hyperdoped Si nanocrystals (NCs). In this work bulk Si with the resistivity as low as ∼ 0.8 (40) mΩ•cm has been produced by hot pressing P (B)-hyperdoped Si NCs. The dopant type is found to make a difference for the sintering of Si NCs during the hot pressing. Bulk Si hot-pressed from P-hyperdoped Si NCs is more compact than that hot-pressed from B-hyperdoped Si NCs when the hot-pressing temperature is the same. This leads to the fact that P is more effectively activated to produce free carriers than B in the hot-pressed bulk Si. Compared with the dopant concentration, the hot-pressing temperature more significantly affects the structural and electrical properties of hot-pressed bulk Si. With the increase of the hot-pressing temperature the density of hot-pressed bulk Si increases. The highest carrier concentration (lowest resistivity) of bulk Si hot-pressed from B- or P-hyperdoped Si NCs is obtained at the highest hot-pressing temperature of 1050 °C. The mobility of carriers in the hot-pressed bulk Si is low (≤  ∼ 30 cm{sup -2}V{sup -1}s{sup -1}) mainly due to the scattering of carriers induced by structural defects such as pores.

  10. Precision manometer gauge

    DOEpatents

    McPherson, M.J.; Bellman, R.A.

    1982-09-27

    A precision manometer gauge which locates a zero height and a measured height of liquid using an open tube in communication with a reservoir adapted to receive the pressure to be measured. The open tube has a reference section carried on a positioning plate which is moved vertically with machine tool precision. Double scales are provided to read the height of the positioning plate accurately, the reference section being inclined for accurate meniscus adjustment, and means being provided to accurately locate a zero or reference position.

  11. Precision manometer gauge

    DOEpatents

    McPherson, Malcolm J.; Bellman, Robert A.

    1984-01-01

    A precision manometer gauge which locates a zero height and a measured height of liquid using an open tube in communication with a reservoir adapted to receive the pressure to be measured. The open tube has a reference section carried on a positioning plate which is moved vertically with machine tool precision. Double scales are provided to read the height of the positioning plate accurately, the reference section being inclined for accurate meniscus adjustment, and means being provided to accurately locate a zero or reference position.

  12. Precision electron polarimetry

    SciTech Connect

    Chudakov, Eugene A.

    2013-11-01

    A new generation of precise Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. M{\\o}ller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for precision polarimetry at ~300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100\\%-polarized electron target for M{\\o}ller polarimetry.

  13. Precision electron polarimetry

    NASA Astrophysics Data System (ADS)

    Chudakov, E.

    2013-11-01

    A new generation of precise Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. Mo/ller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for precision polarimetry at 300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100%-polarized electron target for Mo/ller polarimetry.

  14. Precision electron polarimetry

    SciTech Connect

    Chudakov, E.

    2013-11-07

    A new generation of precise Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. Mo/ller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for precision polarimetry at 300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100%-polarized electron target for Mo/ller polarimetry.

  15. Precision Heating Process

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A heat sealing process was developed by SEBRA based on technology that originated in work with NASA's Jet Propulsion Laboratory. The project involved connecting and transferring blood and fluids between sterile plastic containers while maintaining a closed system. SEBRA markets the PIRF Process to manufacturers of medical catheters. It is a precisely controlled method of heating thermoplastic materials in a mold to form or weld catheters and other products. The process offers advantages in fast, precise welding or shape forming of catheters as well as applications in a variety of other industries.

  16. Low-resistance 2D/2D ohmic contacts: A universal approach to high-performance WSe2, MoS2, and MoSe2 transistors

    SciTech Connect

    Chuang, Hsun -Jen; Chamlagain, Bhim; Koehler, Michael; Perera, Meeghage Madusanka; Yan, Jiaqiang; Mandrus, David; Tomanek, David; Zhou, Zhixian

    2016-02-04

    Here, we report a new strategy for fabricating 2D/2D low-resistance ohmic contacts for a variety of transition metal dichalcogenides (TMDs) using van der Waals assembly of substitutionally doped TMDs as drain/source contacts and TMDs with no intentional doping as channel materials. We demonstrate that few-layer WSe2 field-effect transistors (FETs) with 2D/2D contacts exhibit low contact resistances of ~0.3 kΩ μm, high on/off ratios up to >109, and high drive currents exceeding 320 μA μm–1. These favorable characteristics are combined with a two-terminal field-effect hole mobility μFE ≈ 2 × 102 cm2 V–1 s–1 at room temperature, which increases to >2 × 103 cm2 V–1 s–1 at cryogenic temperatures. We observe a similar performance also in MoS2 and MoSe2 FETs with 2D/2D drain and source contacts. The 2D/2D low-resistance ohmic contacts presented here represent a new device paradigm that overcomes a significant bottleneck in the performance of TMDs and a wide variety of other 2D materials as the channel materials in postsilicon electronics.

  17. High Precision GPS Measurements

    DTIC Science & Technology

    2010-02-28

    GNSS Service (IGS) database, and magnetic field vectors from the International Geomagnetic Reference Field (IGRF) model [9]. These combined...Additonal correlations between the higher order range error and geomagnetic activity and seasonal variations are also obtained. Fig. 4 shows...clear correlation between the geomagnetic activity and enhanced higher order error at both sites. High Precision GPS Final Report Page 5 Fig.3

  18. Precision liquid level sensor

    DOEpatents

    Field, Michael E.; Sullivan, William H.

    1985-01-01

    A precision liquid level sensor utilizes a balanced R. F. bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge.

  19. Precision liquid level sensor

    DOEpatents

    Field, M.E.; Sullivan, W.H.

    1985-01-29

    A precision liquid level sensor utilizes a balanced R. F. bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge. 2 figs.

  20. Teaching with Precision.

    ERIC Educational Resources Information Center

    Raybould, Ted; Solity, Jonathan

    1982-01-01

    Use of precision teaching principles with learning problem students involves five steps: specifying performance, recording daily behavior, charting daily behavior, recording the teaching approach, and analyzing data. The approach has been successfully implemented through consultation of school psychologists in Walsall, England. (CL)

  1. The Precision Medicine Nation.

    PubMed

    Sabatello, Maya; Appelbaum, Paul S

    2017-07-01

    The United States' ambitious Precision Medicine Initiative proposes to accelerate exponentially the adoption of precision medicine, an approach to health care that tailors disease diagnosis, treatment, and prevention to individual variability in genes, environment, and lifestyle. It aims to achieve this by creating a cohort of volunteers for precision medicine research, accelerating biomedical research innovation, and adopting policies geared toward patients' empowerment. As strategies to implement the PMI are formulated, critical consideration of the initiative's ethical and sociopolitical dimensions is needed. Drawing on scholarship of nationalism and democracy, we discuss the PMI's construction of what we term "genomic citizenship"; the possible normative obligations arising therefrom; and the ethical, legal, and social challenges that will ensue. Although the PMI is a work in progress, discussion of the existing and emerging issues can facilitate the development of policies, structures, and procedures that can maximize the initiative's ability to produce equitable and socially sensitive outcomes. Our analysis can also be applied to other population-based, precision medicine research programs. © 2017 The Hastings Center.

  2. Precision bolometer bridge

    NASA Technical Reports Server (NTRS)

    White, D. R.

    1968-01-01

    Prototype precision bolometer calibration bridge is manually balanced device for indicating dc bias and balance with either dc or ac power. An external galvanometer is used with the bridge for null indication, and the circuitry monitors voltage and current simultaneously without adapters in testing 100 and 200 ohm thin film bolometers.

  3. Precision in Stereochemical Terminology

    ERIC Educational Resources Information Center

    Wade, Leroy G., Jr.

    2006-01-01

    An analysis of relatively new terminology that has given multiple definitions often resulting in students learning principles that are actually false is presented with an example of the new term stereogenic atom introduced by Mislow and Siegel. The Mislow terminology would be useful in some cases if it were used precisely and correctly, but it is…

  4. Precision Antenna Alignment Procedure.

    DTIC Science & Technology

    Precise azimuthal alignment of troposcatter system antennas is achieved by centering on the great circle, the combined pattern of intercepting beams...from two troposcatter antennas. The combined antenna pattern is determined to be centered on and symmetric about the great circle when the Doppler

  5. Targets for Precision Measurements

    NASA Astrophysics Data System (ADS)

    Loveland, W.; Yao, L.; Asner, D. M.; Baker, R. G.; Bundgaard, J.; Burgett, E.; Cunningham, M.; Deaven, J.; Duke, D. L.; Greife, U.; Grimes, S.; Heffner, M.; Hill, T.; Isenhower, D.; Klay, J. L.; Kleinrath, V.; Kornilov, N.; Laptev, A. B.; Massey, T. N.; Meharchand, R.; Qu, H.; Ruz, J.; Sangiorgio, S.; Selhan, B.; Snyder, L.; Stave, S.; Tatishvili, G.; Thornton, R. T.; Tovesson, F.; Towell, D.; Towell, R. S.; Watson, S.; Wendt, B.; Wood, L.

    2014-05-01

    The general properties needed in targets (sources) for high precision, high accuracy measurements are reviewed. The application of these principles to the problem of developing targets for the Fission TPC is described. Longer term issues, such as the availability of actinide materials, improved knowledge of energy losses and straggling and the stability of targets during irradiation are also discussed.

  6. Fabrication of recyclable superhydrophobic cotton fabrics

    NASA Astrophysics Data System (ADS)

    Han, Sang Wook; Park, Eun Ji; Jeong, Myung-Geun; Kim, Il Hee; Seo, Hyun Ook; Kim, Ju Hwan; Kim, Kwang-Dae; Kim, Young Dok

    2017-04-01

    Commercial cotton fabric was coated with SiO2 nanoparticles wrapped with a polydimethylsiloxane (PDMS) layer, and the resulting material surface showed a water contact angle greater than 160°. The superhydrophobic fabric showed resistance to water-soluble contaminants and maintained its original superhydrophobic properties with almost no alteration even after many times of absorption-washing cycles of oil. Moreover, superhydrophobic fabric can be used as a filter to separate oil from water. We demonstrated a simple method of fabrication of superhydrophobic fabric with potential interest for use in a variety of applications.

  7. A passion for precision

    ScienceCinema

    None

    2016-07-12

    For more than three decades, the quest for ever higher precision in laser spectroscopy of the simple hydrogen atom has inspired many advances in laser, optical, and spectroscopic techniques, culminating in femtosecond laser optical frequency combs  as perhaps the most precise measuring tools known to man. Applications range from optical atomic clocks and tests of QED and relativity to searches for time variations of fundamental constants. Recent experiments are extending frequency comb techniques into the extreme ultraviolet. Laser frequency combs can also control the electric field of ultrashort light pulses, creating powerful new tools for the emerging field of attosecond science.Organiser(s): L. Alvarez-Gaume / PH-THNote: * Tea & coffee will be served at 16:00.

  8. A passion for precision

    SciTech Connect

    2010-05-19

    For more than three decades, the quest for ever higher precision in laser spectroscopy of the simple hydrogen atom has inspired many advances in laser, optical, and spectroscopic techniques, culminating in femtosecond laser optical frequency combs  as perhaps the most precise measuring tools known to man. Applications range from optical atomic clocks and tests of QED and relativity to searches for time variations of fundamental constants. Recent experiments are extending frequency comb techniques into the extreme ultraviolet. Laser frequency combs can also control the electric field of ultrashort light pulses, creating powerful new tools for the emerging field of attosecond science.Organiser(s): L. Alvarez-Gaume / PH-THNote: * Tea & coffee will be served at 16:00.

  9. Stirling Microregenerators Fabricated and Tested

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.

    2004-01-01

    A mesoscale Stirling refrigerator patented by the NASA Glenn Research Center is currently under development. This refrigerator has a predicted efficiency of 30 percent of Carnot and potential uses in electronics, sensors, optical and radiofrequency systems, microarrays, and microsystems. The mesoscale Stirling refrigerator is most suited to volume-limited applications that require cooling below the ambient or sink temperature. Primary components of the planar device include two diaphragm actuators that replace the pistons found in traditional-scale Stirling machines and a microregenerator that stores and releases thermal energy to the working gas during the Stirling cycle. Diaphragms are used to eliminate frictional losses and bypass leakage concerns associated with pistons, while permitting reversal of the hot and cold sides of the device during operation to allow precise temperature control. Three candidate microregenerators were fabricated under NASA grants for initial evaluation: two constructed of porous ceramic, which were fabricated by Johns Hopkins Applied Physics Laboratory, and one made of multiple layers of nickel and photoresist, which was fabricated by Polar Thermal Technologies. The candidate regenerators are being tested by Johns Hopkins Applied Physics in a custom piezoelectric-actuated test apparatus designed to produce the Stirling refrigeration cycle. In parallel with the regenerator testing, Johns Hopkins is using deep reactive ion etching to fabricate electrostatically driven, comb-drive diaphragm actuators. These actuators will drive the Stirling cycle in the prototype device. The top photograph shows the porous ceramic microregenerators. Two microregenerators were fabricated with coarse pores and two with fine pores. The bottom photograph shows the test apparatus parts for evaluating the microregenerators, including the layered nickel-and-photoresist regenerator fabricated using LIGA techniques.

  10. Fabrication of Submillimeter Axisymmetric Optical Components

    NASA Technical Reports Server (NTRS)

    Grudinin, Ivan; Savchenkov, Anatoliy; Strekalov, Dmitry

    2007-01-01

    It is now possible to fashion transparent crystalline materials into axisymmetric optical components having diameters ranging from hundreds down to tens of micrometers, whereas previously, the smallest attainable diameter was 500 m. A major step in the fabrication process that makes this possible can be characterized as diamond turning or computer numerically controlled machining on an ultrahigh-precision lathe.

  11. Simplified Fabrication of Helical Copper Antennas

    NASA Technical Reports Server (NTRS)

    Petro, Andrew

    2006-01-01

    A simplified technique has been devised for fabricating helical antennas for use in experiments on radio-frequency generation and acceleration of plasmas. These antennas are typically made of copper (for electrical conductivity) and must have a specific helical shape and precise diameter.

  12. Precision laser aiming system

    DOEpatents

    Ahrens, Brandon R.; Todd, Steven N.

    2009-04-28

    A precision laser aiming system comprises a disrupter tool, a reflector, and a laser fixture. The disrupter tool, the reflector and the laser fixture are configurable for iterative alignment and aiming toward an explosive device threat. The invention enables a disrupter to be quickly and accurately set up, aligned, and aimed in order to render safe or to disrupt a target from a standoff position.

  13. Ultra-Precision Optics

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Under a Joint Sponsored Research Agreement with Goddard Space Flight Center, SEMATECH, Inc., the Silicon Valley Group, Inc. and Tinsley Laboratories, known as SVG-Tinsley, developed an Ultra-Precision Optics Manufacturing System for space and microlithographic applications. Continuing improvements in optics manufacture will be able to meet unique NASA requirements and the production needs of the lithography industry for many years to come.

  14. FMS precision machining

    SciTech Connect

    Burnham, M.W.

    1980-01-01

    In evaluating the technical obstacles and accuracy limits to producing a Precision Flexible Manufacturing System, a current system is subjected to an error budget analysis. It is noted that to make complex part geometries with tolerances in the lower thousandths range, machining to tenths is required for process control. Actual parts made to tenths are illustrated, along with a discussion of the requirements for automation and for process control.

  15. Precision Engineering - SRO 154.

    DTIC Science & Technology

    1986-01-01

    supplied with initial parameter guesses and perturbation ranges. Also supplied to the optimization routine is a callable subroutine which uses the...the failure mechanism is a breaking of stable crystal bonds -- a high stress phenomenon. These high stresses result in a continual cycle of wheel...machine tools. Topics Discussed History of Metrology Design of precision machines Methods of magnification Error analysis Surface profilometry Standards of

  16. Precision disablement aiming system

    SciTech Connect

    Monda, Mark J.; Hobart, Clinton G.; Gladwell, Thomas Scott

    2016-02-16

    A disrupter to a target may be precisely aimed by positioning a radiation source to direct radiation towards the target, and a detector is positioned to detect radiation that passes through the target. An aiming device is positioned between the radiation source and the target, wherein a mechanical feature of the aiming device is superimposed on the target in a captured radiographic image. The location of the aiming device in the radiographic image is used to aim a disrupter towards the target.

  17. Precision surface measurement.

    PubMed

    Jiang, X

    2012-08-28

    Surface size, geometry and texture are some of the most influential subjects in the fields of precision and ultra-precision engineering, defining the functional interface through which emerging products operate. Next-generation products demand super-smooth surfaces, freeform geometries or even deterministically introduced microstructures to provide functional performance. Technological progress using these surfaces types is possible only if the associated manufacturing processes are rigorously controlled and the surfaces are measurable. Metrology for advanced surfaces is not established. The current state of the art is challenged in respect to (i) surface characteristics, extremity of size, ultra precision, quality, geometric complexity, or combinations of these aspects, and (ii) measurement technology for the manufacturing environment, in particular, online, non-contact, high speed, ease of use, small footprint and robustness. This study addresses the challenges in this subject area and discusses some fundaments and principles derived from interdisciplinary research. The combination of these aspects is enabling the creation of manufacturing-environment-based measurement technology. This is expected to facilitate advanced surface manufacture over a wide range of sectors, including large science programmes and high-technology engineering.

  18. Low resistance electrode construction

    DOEpatents

    Redey, Laszlo; Karell, Eric J.

    2002-01-01

    An electrochemical cell having a cathode and an anode in contact with an electrolyte. Both electrodes or one of them has an electrically conducting non-metal receptacle defining a chamber with a first metal having a melting point in the range of from about room temperature to about 800.degree. C. inside said receptacle chamber. A second metal with a melting point greater than about 800.degree. C. is in contact with the first metal inside the receptacle chamber and extends outside of the receptacle chamber to form a terminal for the anode. The electrolyte may include the oxides, halides or mixtures thereof of one or more of Li, V, U, Al and the lanthanides. Metal may be produced at the cathode during operation of the cell and oxygen or chlorine at the anode.

  19. Low resistance fuel electrodes

    DOEpatents

    Maskalick, Nichols J.; Folser, George R.

    1989-01-01

    An electrode 6 bonded to a solid, ion conducting electrolyte 5 is made, where the electrode 6 comprises a ceramic metal oxide 18, metal particles 17, and heat stable metal fibers 19, where the metal fibers provide a matrix structure for the electrode. The electrolyte 5 can be bonded to an air electrode cathode 4, to provide an electrochemical cell 2, preferably of tubular design.

  20. R&D 100, 2016: Stress-Induced Fabrication

    ScienceCinema

    Fan, Hongyou; Brennan, Tom; Wise, Jack; Liu, Sheng; Hickman, Randy

    2016-12-09

    Stress-induced fabrication (SIF) uses compressive mechanical stress to create new nanomaterials with lower production costs and enhanced materials performance compared to traditional fabrication routes. Simple, innovative, and with more degrees of freedom than current chemical synthesis methods, SIF uses physical force instead of chemistry applied to form new nanomaterials with precisely controlled structure and tunable properties.

  1. R&D 100, 2016: Stress-Induced Fabrication

    SciTech Connect

    Fan, Hongyou; Brennan, Tom; Wise, Jack; Liu, Sheng; Hickman, Randy

    2016-11-07

    Stress-induced fabrication (SIF) uses compressive mechanical stress to create new nanomaterials with lower production costs and enhanced materials performance compared to traditional fabrication routes. Simple, innovative, and with more degrees of freedom than current chemical synthesis methods, SIF uses physical force instead of chemistry applied to form new nanomaterials with precisely controlled structure and tunable properties.

  2. Polymorphous computing fabric

    DOEpatents

    Wolinski, Christophe Czeslaw [Los Alamos, NM; Gokhale, Maya B [Los Alamos, NM; McCabe, Kevin Peter [Los Alamos, NM

    2011-01-18

    Fabric-based computing systems and methods are disclosed. A fabric-based computing system can include a polymorphous computing fabric that can be customized on a per application basis and a host processor in communication with said polymorphous computing fabric. The polymorphous computing fabric includes a cellular architecture that can be highly parameterized to enable a customized synthesis of fabric instances for a variety of enhanced application performances thereof. A global memory concept can also be included that provides the host processor random access to all variables and instructions associated with the polymorphous computing fabric.

  3. 8. VIEW OF A MOLD FOR PRECISION CASTING. THE MOLD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW OF A MOLD FOR PRECISION CASTING. THE MOLD WAS USED IN FOUNDRY OPERATIONS THAT CAST PLUTONIUM EITHER AS INGOTS SUITABLE FOR ROLLING AND FURTHER WROUGHT PROCESSING OR INTO SHAPES AMENABLE TO DIRECT MACHINING OPERATIONS. (5/6/59) - Rocky Flats Plant, Plutonium Fabrication, Central section of Plant, Golden, Jefferson County, CO

  4. Low-resistance magnetic tunnel junctions prepared by partial remote plasma oxidation of 0.9 nm Al barriers

    SciTech Connect

    Ferreira, Ricardo; Freitas, Paulo P.; MacKenzie, Maureen; Chapman, John N.

    2005-05-09

    Current perpendicular to the plane read-head elements suitable for high-density magnetic storage require low resistance while maintaining a reasonable magnetoresistive (MR) signal (RxA<1 {omega} {mu}m{sup 2} and MR>20% for areal densities >200 Gb/in{sup 2}). This letter shows that competitive low RxA junctions can be produced using underoxidized barriers starting from 0.9 nm thick Al layers. For as-deposited junctions, tunneling magnetoresistance (TMR) {approx}20% for RxA{approx}2-15 {omega} {mu}m{sup 2} is obtained, while in the RxA{approx}60-150 {omega} {mu}m{sup 2} range, TMR values between 40% to 45% are achieved. A limited number of junctions exhibits considerably lower RxA values with respect to the average, while keeping a similar MR (down to 0.44 {omega} {mu}m{sup 2} with TMR of 20% and down to 2.2 {omega} {mu}m{sup 2} with TMR of 52%). Experimental data suggest that current confinement to small regions (barrier defects/hot spots) may explain these results.

  5. Pediatric Artificial Lung: A Low-Resistance Pumpless Artificial Lung Alleviates an Acute Lamb Model of Increased Right Ventricle Afterload.

    PubMed

    Alghanem, Fares; Bryner, Benjamin S; Jahangir, Emilia M; Fernando, Uditha P; Trahanas, John M; Hoffman, Hayley R; Bartlett, Robert H; Rojas-Peña, Alvaro; Hirschl, Ronald B

    Lung disease in children often results in pulmonary hypertension and right heart failure. The availability of a pediatric artificial lung (PAL) would open new approaches to the management of these conditions by bridging to recovery in acute disease or transplantation in chronic disease. This study investigates the efficacy of a novel PAL in alleviating an animal model of pulmonary hypertension and increased right ventricle afterload. Five juvenile lambs (20-30 kg) underwent PAL implantation in a pulmonary artery to left atrium configuration. Induction of disease involved temporary, reversible occlusion of the right main pulmonary artery. Hemodynamics, pulmonary vascular input impedance, and right ventricle efficiency were measured under 1) baseline, 2) disease, and 3) disease + PAL conditions. The disease model altered hemodynamics variables in a manner consistent with pulmonary hypertension. Subsequent PAL attachment improved pulmonary artery pressure (p = 0.018), cardiac output (p = 0.050), pulmonary vascular input impedance (Z.0 p = 0.028; Z.1 p = 0.058), and right ventricle efficiency (p = 0.001). The PAL averaged resistance of 2.3 ± 0.8 mm Hg/L/min and blood flow of 1.3 ± 0.6 L/min. This novel low-resistance PAL can alleviate pulmonary hypertension in an acute animal model and demonstrates potential for use as a bridge to lung recovery or transplantation in pediatric patients with significant pulmonary hypertension refractory to medical therapies.

  6. Low resistance tungsten films on GaAs deposited by means of rapid thermal low pressure chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Katz, A.; Feingold, A.; Nakahara, S.; Pearton, S. J.; Lane, E.

    1992-08-01

    Low resistance tungsten (W) films were deposited onto GaAs substrates by means of rapid thermal low pressure chemical vapor deposition (RT-LPCVD), using tungsten hexafluoride (WF6) gas reduced by hydrogen (H2). Deposition temperatures up to 550 °C for durations of up to 30 s were explored, resulting in deposition of relatively pure W films (containing less than 2% O2 and C). Post-deposition sintering of the layers led to significant reduction of the resistivity to values as low as 50 μΩ cm. The efficiency of the deposition improved upon increasing the H2 flow rate up to 1250 sccm resulting in a deposition rate of about 10 nm/s at a total chamber pressure of 3.5 Torr and temperature of 500 °C. The films appeared to be polycrystalline with a very fine grain structure, regardless of the deposition temperature with good morphology and underwent a limited reaction with the underlying GaAs substrates.

  7. A low resistance microfluidic system for the creation of stable concentration gradients in a defined 3D microenvironment

    PubMed Central

    Amadi, Ovid C.; Steinhauser, Matthew L.; Nishi, Yuichi; Chung, Seok; Kamm, Roger D.; McMahon, Andrew P.

    2011-01-01

    The advent of microfluidic technology allows control and interrogation of cell behavior by defining the local microenvironment with an assortment of biochemical and biophysical stimuli. Many approaches have been developed to create gradients of soluble factors, but the complexity of such systems or their inability to create defined and controllable chemical gradients has limited their widespread implementation. Here we describe a new microfluidic device which employs a parallel arrangement of wells and channels to create stable, linear concentration gradients in a gel region between a source and a sink well. Pressure gradients between the source and sink wells are dissipated through low resistance channels in parallel with the gel channel, thus minimizing the convection of solute in this region. We demonstrate the ability of the new device to quantitate chemotactic responses in a variety of cell types, yielding a complete profile of the migratory response and representing the total number of migrating cells and the distance each cell has migrated. Additionally we show the effect of concentration gradients of the morphogen Sonic hedgehog on the specification of differentiating neural progenitors in a 3-dimensional matrix. PMID:20661647

  8. Precision Pointing System Development

    SciTech Connect

    BUGOS, ROBERT M.

    2003-03-01

    The development of precision pointing systems has been underway in Sandia's Electronic Systems Center for over thirty years. Important areas of emphasis are synthetic aperture radars and optical reconnaissance systems. Most applications are in the aerospace arena, with host vehicles including rockets, satellites, and manned and unmanned aircraft. Systems have been used on defense-related missions throughout the world. Presently in development are pointing systems with accuracy goals in the nanoradian regime. Future activity will include efforts to dramatically reduce system size and weight through measures such as the incorporation of advanced materials and MEMS inertial sensors.

  9. Precision Robotic Assembly Machine

    ScienceCinema

    None

    2016-07-12

    The world's largest laser system is the National Ignition Facility (NIF), located at Lawrence Livermore National Laboratory. NIF's 192 laser beams are amplified to extremely high energy, and then focused onto a tiny target about the size of a BB, containing frozen hydrogen gas. The target must be perfectly machined to incredibly demanding specifications. The Laboratory's scientists and engineers have developed a device called the "Precision Robotic Assembly Machine" for this purpose. Its unique design won a prestigious R&D-100 award from R&D Magazine.

  10. Precise Measurement for Manufacturing

    NASA Technical Reports Server (NTRS)

    2003-01-01

    A metrology instrument known as PhaseCam supports a wide range of applications, from testing large optics to controlling factory production processes. This dynamic interferometer system enables precise measurement of three-dimensional surfaces in the manufacturing industry, delivering speed and high-resolution accuracy in even the most challenging environments.Compact and reliable, PhaseCam enables users to make interferometric measurements right on the factory floor. The system can be configured for many different applications, including mirror phasing, vacuum/cryogenic testing, motion/modal analysis, and flow visualization.

  11. Precision Robotic Assembly Machine

    SciTech Connect

    2009-08-14

    The world's largest laser system is the National Ignition Facility (NIF), located at Lawrence Livermore National Laboratory. NIF's 192 laser beams are amplified to extremely high energy, and then focused onto a tiny target about the size of a BB, containing frozen hydrogen gas. The target must be perfectly machined to incredibly demanding specifications. The Laboratory's scientists and engineers have developed a device called the "Precision Robotic Assembly Machine" for this purpose. Its unique design won a prestigious R&D-100 award from R&D Magazine.

  12. Precision electroweak measurements

    SciTech Connect

    Demarteau, M.

    1996-11-01

    Recent electroweak precision measurements fro {ital e}{sup +}{ital e}{sup -} and {ital p{anti p}} colliders are presented. Some emphasis is placed on the recent developments in the heavy flavor sector. The measurements are compared to predictions from the Standard Model of electroweak interactions. All results are found to be consistent with the Standard Model. The indirect constraint on the top quark mass from all measurements is in excellent agreement with the direct {ital m{sub t}} measurements. Using the world`s electroweak data in conjunction with the current measurement of the top quark mass, the constraints on the Higgs` mass are discussed.

  13. Instrument Attitude Precision Control

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan

    2004-01-01

    A novel approach is presented in this paper to analyze attitude precision and control for an instrument gimbaled to a spacecraft subject to an internal disturbance caused by a moving component inside the instrument. Nonlinear differential equations of motion for some sample cases are derived and solved analytically to gain insight into the influence of the disturbance on the attitude pointing error. A simple control law is developed to eliminate the instrument pointing error caused by the internal disturbance. Several cases are presented to demonstrate and verify the concept presented in this paper.

  14. Precision flyer initiator

    DOEpatents

    Frank, A.M.; Lee, R.S.

    1998-05-26

    A precision flyer initiator forms a substantially spherical detonation wave in a high explosive (HE) pellet. An explosive driver, such as a detonating cord, a wire bridge circuit or a small explosive, is detonated. A flyer material is sandwiched between the explosive driver and an end of a barrel that contains an inner channel. A projectile or ``flyer`` is sheared from the flyer material by the force of the explosive driver and projected through the inner channel. The flyer than strikes the HE pellet, which is supported above a second end of the barrel by a spacer ring. A gap or shock decoupling material delays the shock wave in the barrel from predetonating the HE pellet before the flyer. A spherical detonation wave is formed in the HE pellet. Thus, a shock wave traveling through the barrel fails to reach the HE pellet before the flyer strikes the HE pellet. The precision flyer initiator can be used in mining devices, well-drilling devices and anti-tank devices. 10 figs.

  15. Precision flyer initiator

    DOEpatents

    Frank, Alan M.; Lee, Ronald S.

    1998-01-01

    A precision flyer initiator forms a substantially spherical detonation wave in a high explosive (HE) pellet. An explosive driver, such as a detonating cord, a wire bridge circuit or a small explosive, is detonated. A flyer material is sandwiched between the explosive driver and an end of a barrel that contains an inner channel. A projectile or "flyer" is sheared from the flyer material by the force of the explosive driver and projected through the inner channel. The flyer than strikes the HE pellet, which is supported above a second end of the barrel by a spacer ring. A gap or shock decoupling material delays the shock wave in the barrel from predetonating the HE pellet before the flyer. A spherical detonation wave is formed in the HE pellet. Thus, a shock wave traveling through the barrel fails to reach the HE pellet before the flyer strikes the HE pellet. The precision flyer initiator can be used in mining devices, well-drilling devices and anti-tank devices.

  16. Precision animal breeding.

    PubMed

    Flint, A P F; Woolliams, J A

    2008-02-12

    We accept that we are responsible for the quality of life of animals in our care. We accept that the activities of man affect all the living things with which we share this planet. But we are slow to realize that as a result we have a duty of care for all living things. That duty extends to the breeding of animals for which we are responsible. When animals are bred by man for a purpose, the aim should be to meet certain goals: to improve the precision with which breeding outcomes can be predicted; to avoid the introduction and advance of characteristics deleterious to well-being; and to manage genetic resources and diversity between and within populations as set out in the Convention on Biological Diversity. These goals are summed up in the phrase precision animal breeding. They should apply whether animals are bred as sources of usable products or services for medical or scientific research, for aesthetic or cultural considerations, or as pets. Modern molecular and quantitative genetics and advances in reproductive physiology provide the tools with which these goals can be met.

  17. Micromechanical silicon precision scale

    NASA Astrophysics Data System (ADS)

    Oja, Aarne S.; Sillanpaa, Teuvo; Seppae, H.; Kiihamaki, Jyrki; Seppala, P.; Karttunen, Jani; Riski, Kari

    2000-04-01

    A micro machined capacitive silicon scale has been designed and fabricated. It is intended for weighing masses on the order of 1 g at the resolution of about 1 ppm and below. The device consists of a micro machined SOI chip which is anodically bonded to a glass chip. The flexible electrode is formed in the SOI device layer. The other electrode is metallized on the glass and is divided into three sections. The sections are used for detecting tilting of the top electrode due to a possible off-centering of the mass load. The measuring circuit implements electrostatic force feedback and keeps the top electrode at a constant horizontal position irrespective of its mass loading. First measurements have demonstrated the stability allowing measurement of 1 g masses at an accuracy of 2...3 ppm.

  18. Fabrication of a metal-cored multi-barrelled microiontophoresis assembly.

    PubMed

    Hellier, M; Boers, P; Lambert, G A

    1990-04-01

    A method is described for fabrication of 7-barrelled microiontophoresis electrodes with a center barrel of platinum-coated tungsten. The electrodes require a minimum of expensive apparatus and can be fabricated in an hour or two. The electrodes have low recording impedance (typically 100 k omega and low resistance iontophoresis barrels (typically 20-50 M omega). Compared to electrodes with a micropipette recording barrel, these electrodes are practically noise-free and can pass ionotophoretic currents of up to 200 nA without an appreciable increase in recording noise.

  19. Precision Joining Center

    NASA Technical Reports Server (NTRS)

    Powell, John W.

    1991-01-01

    The establishment of a Precision Joining Center (PJC) is proposed. The PJC will be a cooperatively operated center with participation from U.S. private industry, the Colorado School of Mines, and various government agencies, including the Department of Energy's Nuclear Weapons Complex (NWC). The PJC's primary mission will be as a training center for advanced joining technologies. This will accomplish the following objectives: (1) it will provide an effective mechanism to transfer joining technology from the NWC to private industry; (2) it will provide a center for testing new joining processes for the NWC and private industry; and (3) it will provide highly trained personnel to support advance joining processes for the NWC and private industry.

  20. Precision Spectroscopy of Tellurium

    NASA Astrophysics Data System (ADS)

    Coker, James; Furneaux, John; Dept. of Physics and Astronomy Team

    2013-05-01

    Tellurium (Te2) is widely used as a frequency reference, and although a standard atlas encompassing over 5200 cm-1 already exists, Doppler broadening present in that work buries a significant portion of the features. More recent but less complete studies of Te2 exist which do not exhibit Doppler broadening, and this work adds to that knowledge a few hundred transitions in the vicinity of 444 nm. Using a Fabry Perot cavity in a shock-absorbing, temperature and pressure regulated chamber, locked to a Zeeman stabilized HeNe laser, we measure changes in frequency of our diode laser to ~1 MHz precision. This diode laser is scanned over 1000 GHz for use in a saturated-absorption spectroscopy cell filled with Te2 vapor. This data allows for new studies of the excited states of Te2.

  1. Precision spectroscopy of Helium

    SciTech Connect

    Cancio, P.; Giusfredi, G.; Mazzotti, D.; De Natale, P.; De Mauro, C.; Krachmalnicoff, V.; Inguscio, M.

    2005-05-05

    Accurate Quantum-Electrodynamics (QED) tests of the simplest bound three body atomic system are performed by precise laser spectroscopic measurements in atomic Helium. In this paper, we present a review of measurements between triplet states at 1083 nm (23S-23P) and at 389 nm (23S-33P). In 4He, such data have been used to measure the fine structure of the triplet P levels and, then, to determine the fine structure constant when compared with equally accurate theoretical calculations. Moreover, the absolute frequencies of the optical transitions have been used for Lamb-shift determinations of the levels involved with unprecedented accuracy. Finally, determination of the He isotopes nuclear structure and, in particular, a measurement of the nuclear charge radius, are performed by using hyperfine structure and isotope-shift measurements.

  2. Precision Medicine in Cancer Treatment

    Cancer.gov

    Precision medicine helps doctors select cancer treatments that are most likely to help patients based on a genetic understanding of their disease. Learn about the promise of precision medicine and the role it plays in cancer treatment.

  3. Precision Spectroscopy of Tellurium

    NASA Astrophysics Data System (ADS)

    Coker, J.; Furneaux, J. E.

    2013-06-01

    Tellurium (Te_2) is widely used as a frequency reference, largely due to the fact that it has an optical transition roughly every 2-3 GHz throughout a large portion of the visible spectrum. Although a standard atlas encompassing over 5200 cm^{-1} already exists [1], Doppler broadening present in that work buries a significant portion of the features [2]. More recent studies of Te_2 exist which do not exhibit Doppler broadening, such as Refs. [3-5], and each covers different parts of the spectrum. This work adds to that knowledge a few hundred transitions in the vicinity of 444 nm, measured with high precision in order to improve measurement of the spectroscopic constants of Te_2's excited states. Using a Fabry Perot cavity in a shock-absorbing, temperature and pressure regulated chamber, locked to a Zeeman stabilized HeNe laser, we measure changes in frequency of our diode laser to ˜1 MHz precision. This diode laser is scanned over 1000 GHz for use in a saturated-absorption spectroscopy cell filled with Te_2 vapor. Details of the cavity and its short and long-term stability are discussed, as well as spectroscopic properties of Te_2. References: J. Cariou, and P. Luc, Atlas du spectre d'absorption de la molecule de tellure, Laboratoire Aime-Cotton (1980). J. Coker et al., J. Opt. Soc. Am. B {28}, 2934 (2011). J. Verges et al., Physica Scripta {25}, 338 (1982). Ph. Courteille et al., Appl. Phys. B {59}, 187 (1994) T.J. Scholl et al., J. Opt. Soc. Am. B {22}, 1128 (2005).

  4. Fabrication of photovoltaic laser energy converterby MBE

    NASA Technical Reports Server (NTRS)

    Lu, Hamilton; Wang, Scott; Chan, W. S.

    1993-01-01

    A laser-energy converter, fabricated by molecular beam epitaxy (MBE), was developed. This converter is a stack of vertical p-n junctions connected in series by low-resistivity, lattice matched CoSi2 layers to achieve a high conversion efficiency. Special high-temperature electron-beam (e-beam) sources were developed especially for the MBE growth of the junctions and CoSi2 layers. Making use of the small (greater than 1.2 percent) lattice mismatch between CoSi2 and Si layers, high-quality and pinhole-free epilayers were achieved, providing a capability of fabricating all the junctions and connecting layers as a single growth process with one pumpdown. Well-defined multiple p-n junctions connected by CoSi2 layers were accomplished by employing a low growth temperature (greater than 700 C) and a low growth rate (less than 0.5 microns/hour). Producing negligible interdiffusion, the low growth temperature and rate also produced negligible pinholes in the CoSi2 layers. For the first time, a stack of three p-n junctions connected by two 10(exp -5) Ohm-cm CoSi2 layers was achieved, meeting the high conversion efficiency requirement. This process can now be optimized for high growth rate to form a practical converter with 10 p-n junctions in the stack.

  5. Potassium-argon (argon-argon), structural fabrics

    USGS Publications Warehouse

    Cosca, Michael A.; Rink, W. Jack; Thompson, Jereon

    2014-01-01

    Definition: 40Ar/39Ar geochronology of structural fabrics: The application of 40Ar/39Ar methods to date development of structural fabrics in geologic samples. Introduction: Structural fabrics develop during rock deformation at variable pressures (P), temperatures (T), fluid compositions (X), and time (t). Structural fabrics are represented in rocks by features such as foliations and shear zones developed at the mm to km scale. In ideal cases, the P-T-X history of a given structural fabric can be constrained using stable isotope, cation exchange, and/or mineral equilibria thermobarometry (Essene 1989). The timing of structural fabric development can be assessed qualitatively using geologic field observations or quantitatively using isotope-based geochronology. High-precision geochronology of the thermal and fluid flow histories associated with structural fabric development can answer fundamental geologic questions including (1) when hydrothermal fluids transported and deposited ore minerals, ...

  6. Fabrication of micro metallic valve and pump

    NASA Astrophysics Data System (ADS)

    Yang, Ming; Kabasawa, Yasunari; Ito, Kuniyoshi

    2010-03-01

    Fabrication of micro devices by using micro metal forming was proposed by the authors. We developed a desktop servo-press machine with precise tooling system. Precise press forming processes including micro forging and micro joining has been carried out in a progressive die. In this study, micro metallic valve and pump were fabricated by using the precise press forming. The components are made of sheet metals, and assembled in to a unit in the progressive die. A micro check-valve with a diameter of 3mm and a length of 3.2mm was fabricated, and the property of flow resistance was evaluated. The results show that the check valve has high property of leakage proof. Since the valve is a unit parts with dimensions of several millimeters, it has advantage to be adapted to various pump design. Here, two kinds of micro pumps with the check-valves were fabricated. One is diaphragm pump actuated by vibration of the diaphragm, and another is tube-shaped pump actuated by resonation. The flow quantities of the pumps were evaluated and the results show that both of the pumps have high pumping performance.

  7. Fabrication of micro metallic valve and pump

    NASA Astrophysics Data System (ADS)

    Yang, Ming; Kabasawa, Yasunari; Ito, Kuniyoshi

    2009-12-01

    Fabrication of micro devices by using micro metal forming was proposed by the authors. We developed a desktop servo-press machine with precise tooling system. Precise press forming processes including micro forging and micro joining has been carried out in a progressive die. In this study, micro metallic valve and pump were fabricated by using the precise press forming. The components are made of sheet metals, and assembled in to a unit in the progressive die. A micro check-valve with a diameter of 3mm and a length of 3.2mm was fabricated, and the property of flow resistance was evaluated. The results show that the check valve has high property of leakage proof. Since the valve is a unit parts with dimensions of several millimeters, it has advantage to be adapted to various pump design. Here, two kinds of micro pumps with the check-valves were fabricated. One is diaphragm pump actuated by vibration of the diaphragm, and another is tube-shaped pump actuated by resonation. The flow quantities of the pumps were evaluated and the results show that both of the pumps have high pumping performance.

  8. Mathematics for modern precision engineering.

    PubMed

    Scott, Paul J; Forbes, Alistair B

    2012-08-28

    The aim of precision engineering is the accurate control of geometry. For this reason, mathematics has a long association with precision engineering: from the calculation and correction of angular scales used in surveying and astronomical instrumentation to statistical averaging techniques used to increase precision. This study illustrates the enabling role the mathematical sciences are playing in precision engineering: modelling physical processes, instruments and complex geometries, statistical characterization of metrology systems and error compensation.

  9. Fabrication of brittle materials -- current status

    SciTech Connect

    Scattergood, R.O.

    1988-12-01

    The research initiatives in the area of precision fabrication will be continued in the upcoming year. Three students, T. Bifano (PhD), P. Blake (PhD) and E. Smith (MS), finished their research programs in the last year. Sections 13 and 14 will summarize the essential results from the work of the Materials Engineering students Blake and Smith. Further details will be presented in forthcoming publications that are now in preparation. The results from Bifano`s thesis have been published in adequate detail and need not be summarized further. Three new students, S. Blackley (MS), H. Paul (PhD), and S. Smith (PhD) have joined the program and will continue the research efforts in precision fabrication. The programs for these students will be outlined in Sections 15 and 16. Because of the success of the earlier work in establishing new process models and experimental techniques for the study of diamond turning and diamond grinding, the new programs will, in part, build upon the earlier work. This is especially true for investigations concerned with brittle materials. The basic understanding of material response of nominally brittle materials during machining or grinding operations remains as a challenge. The precision fabrication of brittle materials will continue as an area of emphasis for the Precision Engineering Center.

  10. Fabrication of Superhydrophilic Wool Fabrics By Nanotechnology

    NASA Astrophysics Data System (ADS)

    Chen, Dong

    Because of the fatty layer on its surface, wool fiber is hydrophobic, which results in poor water absorption and wicking properties that affect the comfort of wool textiles. The purpose of this research is to improve the wettability and comfort of wool textiles using nanotechnology. To reveal the knowledge gaps and ensure the originality of this study, a critical review of literature was conducted in relevant areas. To achieve the objectives of the research, a simple method for fabricating environmentally stable superhydrophilic wool fabrics was developed. Silica sols with diameters of 27 nm were prepared and then coated on the surface of pristine wool fibers to form an ultrathin layer, increasing both the surface roughness and energy. The morphology and composition of silica-sol-coated wool fabrics were characterized by a combination of SEM, TEM, FTIR, and XPS measurements. After evaluating the wettability and washing durability of the silica-sol-coated wool fabrics, it was found that the durability of these wool fabrics needed to be improved. To achieve superhydrophilic wool fabrics with good washing durability, reactive siloxane was functionalized on wool fiber surface, and an ultrathin silica nanoparticles layer was grafted on the surface by in-situ growth method. To evaluate the wettability change of silica grafted wool fabric, in addition to the contact angle, in-depth characterizations of water absorbing and drying properties of wool fabrics were measured. According to Chinese National Standard (GB/T 21655.1-2008 and GB/T 21655.2-2009), the prepared silica grafted wool fabric has excellent water absorbing and quick drying properties that can be maintained after washing 20 times in a washing machine. The strategy of siloxane bonding and in-situ growth was successfully extended to durable multifunctional wool fabrics combined with superhydrophilic, self-cleaning, and antibacterial properties. To study the relationships between functional properties and nano

  11. Precision cosmological parameter estimation

    NASA Astrophysics Data System (ADS)

    Fendt, William Ashton, Jr.

    2009-09-01

    Experimental efforts of the last few decades have brought. a golden age to mankind's endeavor to understand tine physical properties of the Universe throughout its history. Recent measurements of the cosmic microwave background (CMB) provide strong confirmation of the standard big bang paradigm, as well as introducing new mysteries, to unexplained by current physical models. In the following decades. even more ambitious scientific endeavours will begin to shed light on the new physics by looking at the detailed structure of the Universe both at very early and recent times. Modern data has allowed us to begins to test inflationary models of the early Universe, and the near future will bring higher precision data and much stronger tests. Cracking the codes hidden in these cosmological observables is a difficult and computationally intensive problem. The challenges will continue to increase as future experiments bring larger and more precise data sets. Because of the complexity of the problem, we are forced to use approximate techniques and make simplifying assumptions to ease the computational workload. While this has been reasonably sufficient until now, hints of the limitations of our techniques have begun to come to light. For example, the likelihood approximation used for analysis of CMB data from the Wilkinson Microwave Anistropy Probe (WMAP) satellite was shown to have short falls, leading to pre-emptive conclusions drawn about current cosmological theories. Also it can he shown that an approximate method used by all current analysis codes to describe the recombination history of the Universe will not be sufficiently accurate for future experiments. With a new CMB satellite scheduled for launch in the coming months, it is vital that we develop techniques to improve the analysis of cosmological data. This work develops a novel technique of both avoiding the use of approximate computational codes as well as allowing the application of new, more precise analysis

  12. Space reactor shielding fabrication

    NASA Technical Reports Server (NTRS)

    Welch, F. H.

    1972-01-01

    The fabrication of space reactor neutron shielding by a melting and casting process utilizing lithium hydride is described. The first neutron shield fabricated is a large pancake shape 86 inches in diameter, containing about 1700 pounds of lithium hydride. This shield, fabricated by the unique melting and casting process, is the largest lithium hydride shield ever built.

  13. Precise measurement of planeness.

    PubMed

    Schulz, G; Schwider, J

    1967-06-01

    Interference methods are reviewed-particularly those developed at the German Academy of Sciences in Berlin-with which the deviations of an optically flat surface from the ideal plane can be measured with a high degree of exactness. One aid to achieve this is the relative methods which measure the differences in planeness between two surfaces. These are then used in the absolute methods which determine the absolute planeness of a surface. This absolute determination can be effected in connection with a liquid surface, or (as done by the authors) only by suitable evaluation of relative measurements between unknown plates in various positional combinations. Experimentally, one uses two- or multiple-beam interference fringes of equal thickness(1) or of equal inclination. The fringes are observed visually, scanned, or photographed, and in part several wavelengths or curves of equal density (Aquidensiten) are employed. The survey also brings the following new methods: a relative method, where, with the aid of fringes of superposition, the fringe separation is subdivided equidistantly thus achieving an increase of measuring precision, and an absolute method which determines the deviations of a surface from ideal planeness along arbitrary central sections, without a liquid surface, from four relative interference photographs.

  14. Arrival Metering Precision Study

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Mercer, Joey; Homola, Jeffrey; Hunt, Sarah; Gomez, Ashley; Bienert, Nancy; Omar, Faisal; Kraut, Joshua; Brasil, Connie; Wu, Minghong, G.

    2015-01-01

    This paper describes the background, method and results of the Arrival Metering Precision Study (AMPS) conducted in the Airspace Operations Laboratory at NASA Ames Research Center in May 2014. The simulation study measured delivery accuracy, flight efficiency, controller workload, and acceptability of time-based metering operations to a meter fix at the terminal area boundary for different resolution levels of metering delay times displayed to the air traffic controllers and different levels of airspeed information made available to the Time-Based Flow Management (TBFM) system computing the delay. The results show that the resolution of the delay countdown timer (DCT) on the controllers display has a significant impact on the delivery accuracy at the meter fix. Using the 10 seconds rounded and 1 minute rounded DCT resolutions resulted in more accurate delivery than 1 minute truncated and were preferred by the controllers. Using the speeds the controllers entered into the fourth line of the data tag to update the delay computation in TBFM in high and low altitude sectors increased air traffic control efficiency and reduced fuel burn for arriving aircraft during time based metering.

  15. Precisely Tracking Childhood Death.

    PubMed

    Farag, Tamer H; Koplan, Jeffrey P; Breiman, Robert F; Madhi, Shabir A; Heaton, Penny M; Mundel, Trevor; Ordi, Jaume; Bassat, Quique; Menendez, Clara; Dowell, Scott F

    2017-07-01

    Little is known about the specific causes of neonatal and under-five childhood death in high-mortality geographic regions due to a lack of primary data and dependence on inaccurate tools, such as verbal autopsy. To meet the ambitious new Sustainable Development Goal 3.2 to eliminate preventable child mortality in every country, better approaches are needed to precisely determine specific causes of death so that prevention and treatment interventions can be strengthened and focused. Minimally invasive tissue sampling (MITS) is a technique that uses needle-based postmortem sampling, followed by advanced histopathology and microbiology to definitely determine cause of death. The Bill & Melinda Gates Foundation is supporting a new surveillance system called the Child Health and Mortality Prevention Surveillance network, which will determine cause of death using MITS in combination with other information, and yield cause-specific population-based mortality rates, eventually in up to 12-15 sites in sub-Saharan Africa and south Asia. However, the Gates Foundation funding alone is not enough. We call on governments, other funders, and international stakeholders to expand the use of pathology-based cause of death determination to provide the information needed to end preventable childhood mortality.

  16. Precisely Tracking Childhood Death

    PubMed Central

    Farag, Tamer H.; Koplan, Jeffrey P.; Breiman, Robert F.; Madhi, Shabir A.; Heaton, Penny M.; Mundel, Trevor; Ordi, Jaume; Bassat, Quique; Menendez, Clara; Dowell, Scott F.

    2017-01-01

    Abstract. Little is known about the specific causes of neonatal and under-five childhood death in high-mortality geographic regions due to a lack of primary data and dependence on inaccurate tools, such as verbal autopsy. To meet the ambitious new Sustainable Development Goal 3.2 to eliminate preventable child mortality in every country, better approaches are needed to precisely determine specific causes of death so that prevention and treatment interventions can be strengthened and focused. Minimally invasive tissue sampling (MITS) is a technique that uses needle-based postmortem sampling, followed by advanced histopathology and microbiology to definitely determine cause of death. The Bill & Melinda Gates Foundation is supporting a new surveillance system called the Child Health and Mortality Prevention Surveillance network, which will determine cause of death using MITS in combination with other information, and yield cause-specific population-based mortality rates, eventually in up to 12–15 sites in sub-Saharan Africa and south Asia. However, the Gates Foundation funding alone is not enough. We call on governments, other funders, and international stakeholders to expand the use of pathology-based cause of death determination to provide the information needed to end preventable childhood mortality. PMID:28719334

  17. The effects of high resistance-few repetitions and low resistance-high repetitions resistance training on climbing performance.

    PubMed

    Hermans, Espen; Andersen, Vidar; Saeterbakken, Atle Hole

    2017-05-01

    The aim of the study was to compare the effects of different strength training intensities on climbing performance, climbing-specific tests and a general strength test. Thirty lower grade and intermediate-level climbers participated in a 10-week training programme. The participants were randomized into three groups: high resistance-few repetitions training groups (HR-FR), low resistance-high repetitions training groups (LR-HR) and a control group (CON) which continued climbing/training as usual. Post-testing results demonstrated statistical tendencies for climbing performance improvements in the HR-FR and LR-HR (p = 0.088-0.090, effect size = 0.55-0.73), but no differences were observed between the groups (p = 0.950). For the climbing-specific tests, no differences were observed between the groups (p = 0.507-1.000), but the HR-FR and LR-HR improved their time in both Dead-hang (p = 0.004-0.026) and Bent-arm hang (p < 0.001-0.002). The HR-FR and LR-HR improved their 12RM strength in pull-down (p ≤ 0.001), but not the CON group (p = 0.250). No differences were observed in the CON group in any of the tests (p = 0.190-0.596) with the exception of improvement in Bent-arm Hang (p = 0.018). The training groups reduced their climbing sessions during the intervention compared to the CON group (p = 0.057-0.074). In conclusion, HR-FR and LR-HR training programmes demonstrated an 11% and 12% non-significant improvement in climbing performance despite a 50% reduction in climbing sessions, but improved the results in strength and climbing-specific tests. None of the training intensities was superior compared to the others.

  18. Low resistance, large dimension entrance to the inner cavity of BK channels determined by changing side-chain volume

    PubMed Central

    Niu, Xiaowei

    2011-01-01

    Large-conductance Ca2+- and voltage-activated K+ (BK) channels have the largest conductance (250–300 pS) of all K+-selective channels. Yet, the contributions of the various parts of the ion conduction pathway to the conductance are not known. Here, we examine the contribution of the entrance to the inner cavity to the large conductance. Residues at E321/E324 on each of the four α subunits encircle the entrance to the inner cavity. To determine if 321/324 is accessible from the inner conduction pathway, we measured single-channel current amplitudes before and after exposure and wash of thiol reagents to the intracellular side of E321C and E324C channels. MPA− increased currents and MTSET+ decreased currents, with no difference between positions 321 and 324, indicating that side chains at 321/324 are accessible from the inner conduction pathway and have equivalent effects on conductance. For neutral amino acids, decreasing the size of the entrance to the inner cavity by substituting large side-chain amino acids at 321/324 decreased outward single-channel conductance, whereas increasing the size of the entrance with smaller side-chain substitutions had little effect. Reductions in outward conductance were negated by high [K+]i. Substitutions had little effect on inward conductance. Fitting plots of conductance versus side-chain volume with a model consisting of one variable and one fixed resistor in series indicated an effective diameter and length of the entrance to the inner cavity for wild-type channels of 17.7 and 5.6 Å, respectively, with the resistance of the entrance ∼7% of the total resistance of the conduction pathway. The estimated dimensions are consistent with the structure of MthK, an archaeal homologue to BK channels. Our observations suggest that BK channels have a low resistance, large entrance to the inner cavity, with the entrance being as large as necessary to not limit current, but not much larger. PMID:21576375

  19. Configuring Electronic States in an Atomically Precise Array of Quantum Boxes.

    PubMed

    Nowakowska, Sylwia; Wäckerlin, Aneliia; Piquero-Zulaica, Ignacio; Nowakowski, Jan; Kawai, Shigeki; Wäckerlin, Christian; Matena, Manfred; Nijs, Thomas; Fatayer, Shadi; Popova, Olha; Ahsan, Aisha; Mousavi, S Fatemeh; Ivas, Toni; Meyer, Ernst; Stöhr, Meike; Ortega, J Enrique; Björk, Jonas; Gade, Lutz H; Lobo-Checa, Jorge; Jung, Thomas A

    2016-07-01

    A 2D array of electronically coupled quantum boxes is fabricated by means of on-surface self-assembly assuring ultimate precision of each box. The quantum states embedded in the boxes are configured by adsorbates, whose occupancy is controlled with atomic precision. The electronic interbox coupling can be maintained or significantly reduced by proper arrangement of empty and filled boxes.

  20. A multi-probe micro-fabrication apparatus based on the friction-induced fabrication method

    NASA Astrophysics Data System (ADS)

    Wu, Zhijiang; Song, Chenfei; Guo, Jian; Yu, Bingjun; Qian, Linmao

    2013-12-01

    A novel multi-probe micro-fabrication apparatus was developed based on the friction-induced fabrication method. The main parts of the apparatus include actuating device, loading system, and control system. With a motorized XY linear stage, the maximum fabrication area of 50 mm × 50 mm can be achieved, and the maximum sliding speed of probes can be as high as 10 mm/s. Through locating steel micro balls into indents array, the preparation of multi-probe array can be realized by a simple and low-cost way. The cantilever was designed as a structure of deformable parallelogram with two beams, by which the fabrication force can be precisely controlled. Combining the friction-induced scanning with selective etching in KOH solution, various micro-patterns were fabricated on Si(100) surface without any masks or exposure. As a low-cost and high efficiency fabrication device, the multi-probe micro-fabrication apparatus may encourage the development of friction-induced fabrication method and shed new light on the texture engineering.

  1. Photochemical cutting of fabrics

    DOEpatents

    Piltch, Martin S.

    1994-01-01

    Apparatus for the cutting of garment patterns from one or more layers of fabric. A laser capable of producing laser light at an ultraviolet wavelength is utilized to shine light through a pattern, such as a holographic phase filter, and through a lens onto the one or more layers of fabric. The ultraviolet laser light causes rapid photochemical decomposition of the one or more layers of fabric, but only along the pattern. The balance of the fabric of the one or more layers of fabric is undamaged.

  2. [Precision nutrition in the era of precision medicine].

    PubMed

    Chen, P Z; Wang, H

    2016-12-06

    Precision medicine has been increasingly incorporated into clinical practice and is enabling a new era for disease prevention and treatment. As an important constituent of precision medicine, precision nutrition has also been drawing more attention during physical examinations. The main aim of precision nutrition is to provide safe and efficient intervention methods for disease treatment and management, through fully considering the genetics, lifestyle (dietary, exercise and lifestyle choices), metabolic status, gut microbiota and physiological status (nutrient level and disease status) of individuals. Three major components should be considered in precision nutrition, including individual criteria for sufficient nutritional status, biomarker monitoring or techniques for nutrient detection and the applicable therapeutic or intervention methods. It was suggested that, in clinical practice, many inherited and chronic metabolic diseases might be prevented or managed through precision nutritional intervention. For generally healthy populations, because lifestyles, dietary factors, genetic factors and environmental exposures vary among individuals, precision nutrition is warranted to improve their physical activity and reduce disease risks. In summary, research and practice is leading toward precision nutrition becoming an integral constituent of clinical nutrition and disease prevention in the era of precision medicine.

  3. Precise Truss Assembly Using Commodity Parts and Low Precision Welding

    NASA Technical Reports Server (NTRS)

    Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, W. R.; Correll, Nikolaus

    2014-01-01

    Hardware and software design and system integration for an intelligent precision jigging robot (IPJR), which allows high precision assembly using commodity parts and low-precision bonding, is described. Preliminary 2D experiments that are motivated by the problem of assembling space telescope optical benches and very large manipulators on orbit using inexpensive, stock hardware and low-precision welding are also described. An IPJR is a robot that acts as the precise "jigging", holding parts of a local structure assembly site in place, while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (for this prototype, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. The analysis of the assembly error and the results of building a square structure and a ring structure are discussed. Options for future work, to extend the IPJR paradigm to building in 3D structures at micron precision are also summarized.

  4. Precise Truss Assembly using Commodity Parts and Low Precision Welding

    NASA Technical Reports Server (NTRS)

    Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, William R.; Correll, Nikolaus

    2013-01-01

    We describe an Intelligent Precision Jigging Robot (IPJR), which allows high precision assembly of commodity parts with low-precision bonding. We present preliminary experiments in 2D that are motivated by the problem of assembling a space telescope optical bench on orbit using inexpensive, stock hardware and low-precision welding. An IPJR is a robot that acts as the precise "jigging", holding parts of a local assembly site in place while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (in this case, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. We report the challenges of designing the IPJR hardware and software, analyze the error in assembly, document the test results over several experiments including a large-scale ring structure, and describe future work to implement the IPJR in 3D and with micron precision.

  5. Precision medicine in myasthenia graves: begin from the data precision

    PubMed Central

    Hong, Yu; Xie, Yanchen; Hao, Hong-Jun; Sun, Ren-Cheng

    2016-01-01

    Myasthenia gravis (MG) is a prototypic autoimmune disease with overt clinical and immunological heterogeneity. The data of MG is far from individually precise now, partially due to the rarity and heterogeneity of this disease. In this review, we provide the basic insights of MG data precision, including onset age, presenting symptoms, generalization, thymus status, pathogenic autoantibodies, muscle involvement, severity and response to treatment based on references and our previous studies. Subgroups and quantitative traits of MG are discussed in the sense of data precision. The role of disease registries and scientific bases of precise analysis are also discussed to ensure better collection and analysis of MG data. PMID:27127759

  6. Precise Truss Assembly Using Commodity Parts and Low Precision Welding

    NASA Technical Reports Server (NTRS)

    Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, W. R.; Correll, Nikolaus

    2014-01-01

    Hardware and software design and system integration for an intelligent precision jigging robot (IPJR), which allows high precision assembly using commodity parts and low-precision bonding, is described. Preliminary 2D experiments that are motivated by the problem of assembling space telescope optical benches and very large manipulators on orbit using inexpensive, stock hardware and low-precision welding are also described. An IPJR is a robot that acts as the precise "jigging", holding parts of a local structure assembly site in place, while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (for this prototype, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. The analysis of the assembly error and the results of building a square structure and a ring structure are discussed. Options for future work, to extend the IPJR paradigm to building in 3D structures at micron precision are also summarized.

  7. Precision porcelain jacket crown technique.

    PubMed

    Riley, E J; Sozio, R B; Casthely, F; Wilcko, M T; Sotera, A J

    1975-09-01

    A simple technique for construction of an aluminous porcelain crown has been described. An aluminous core is fabricated without platinum foil on a ceramic refractory die and, when retrieved, serves as a coping on the master cast. The technique and accuracy of fit are illustrated with the fabrication of an aluminous porcelain crown on the Bureau of Standards' full-crown die.

  8. Micro-fabrication Techniques for Target Components

    SciTech Connect

    Miles, R; Hamilton, J; Crawford, J; Ratti, S; Trevino, J; Graff, T; Stockton, C; Harvey, C

    2008-06-10

    Micro-fabrication techniques, derived from the semi-conductor industry, can be used to make a variety of useful mechanical components for targets. A selection of these components including supporting cooling arms for prototype cryogenic inertial confinement fusion targets, stepped and graded density targets for materials dynamics experiments are described. Micro-fabrication enables cost-effective, simultaneous fabrication of multiple high-precision components with complex geometries. Micro-fabrication techniques such as thin-film deposition, photo-lithographic patterning and etch processes normally used in the semi-conductor manufacture industry, can be exploited to make useful mechanical target components. Micro-fabrication processes have in recent years been used to create a number of micro-electro-mechanical systems (MEMS) components such as pressure sensors, accelerometers, ink jet printer heads, microfluidics platforms and the like. These techniques consist primarily of deposition of thin films of material, photo-lithographic patterning and etching processes performed sequentially to produce three dimensional structures using essentially planar processes. While the planar technology can be limiting in terms of the possible geometries of the final product, advantages of using these techniques include the ability to make multiple complex structures simultaneously and cost-effectively. Target components fabricated using these techniques include the supporting cooling arms for cryogenic prototype fusion ignition targets, stepped targets for equation-of-state experiments, and graded density reservoirs for material strength experiments.

  9. Precision Cryogenic Dilatometer

    NASA Technical Reports Server (NTRS)

    Dudik, Matthew; Halverson, Peter; Levine-West, Marie; Marcin, Martin; Peters, Robert D.; Shaklan, Stuart

    2005-01-01

    A dilatometer based on a laser interferometer is being developed to measure mechanical creep and coefficients of thermal expansion (CTEs) of materials at temperatures ranging from ambient down to 15 K. This cryogenic dilatometer has been designed to minimize systematic errors that limit the best previously available dilatometers. At its prototype stage of development, this cryogenic dilatometer yields a strain measurement error of 35 ppb or 1.7 ppb/K CTE measurement error for a 20-K thermal load, for low-expansion materials in the temperature range from 310 down to 30 K. Planned further design refinements that include a provision for stabilization of the laser and addition of a high-precision sample-holding jig are expected to reduce the measurement error to 5-ppb strain error or 0.3-ppb/K CTE error for a 20-K thermal load. The dilatometer (see figure) includes a common-path, differential, heterodyne interferometer; a dual-frequency, stabilized source bench that serves as the light source for the interferometer; a cryogenic chamber in which one places the material sample to be studied; a cryogenic system for cooling the interior of the chamber to the measurement temperature; an ultra-stable alignment stage for positioning the chamber so that the sample is properly positioned with respect to the interferometer; and a data-acquisition and control system. The cryogenic chamber and the interferometer portion of the dilatometer are housed in a vacuum chamber on top of a vibration isolating optical table in a cleanroom. The sample consists of two pieces a pillar on a base both made of the same material. Using reflections of the interferometer beams from the base and the top of the pillar, what is measured is the change in length of the pillar as the temperature in the chamber is changed. In their fundamental optical and electronic principles of operation, the laser light source and the interferometer are similar to those described in Common-Path Heterodyne

  10. Apparatus Makes Precisely Saturated Solutions

    NASA Technical Reports Server (NTRS)

    Pusey, Marc L.

    1989-01-01

    Simple laboratory apparatus establishes equilibrium conditions of temperature and concentration in solutions for use in precise measurements of saturation conditions. With equipment typical measurement of saturation concentration of protein in solution established and measured within about 24 hours. Precisely saturated solution made by passing solvent or solution slowly along column packed with solute at precisely controlled temperature. If necessary, flow stopped for experimentally determined interval to allow equilibrium to be established in column.

  11. Composite materials for precision space reflector panels

    NASA Technical Reports Server (NTRS)

    Tompkins, Stephen S.; Funk, Joan G.; Bowles, David E.; Towell, Timothy W.; Connell, John W.

    1992-01-01

    One of the critical technology needs of large precision reflectors for future astrophysical and optical communications satellites lies in the area of structural materials. Results from a materials research and development program at NASA Langley Research Center to provide materials for these reflector applications are discussed. Advanced materials that meet the reflector panel requirements are identified, and thermal, mechanical and durability properties of candidate materials after exposure to simulated space environments are compared. A parabolic, graphite-phenolic honeycomb composite panel having a surface accuracy of 70.8 microinches rms and an areal weight of 1.17 lbm/sq ft was fabricated with T50/ERL1962 facesheets, a PAEI thermoplastic surface film, and Al and SiO(x) coatings.

  12. Precise mass detector based on carbon nanooscillator

    SciTech Connect

    Lukashenko, S. Golubok, A.; Komissarenko, F.; Veniaminov, A.; Lysak, V.

    2016-06-17

    Precise mass detectors based on an amorphous carbon nanowires, which localized on the top of a tungsten tip were fabricated and investigated. The nanowires were grown in the scanning electron microscope (SEM) chamber using focused electron beam technique. The movement trajectories and amplitude-frequency characteristics of the carbon nanowire oscillators were visualized at low and ambient pressure using SEM and confocal laser scanning microscope (CLSM), respectevely. The SiO{sub 2} and TiO{sub 2} nanospheres were clamped on the top of the carbon nanowires. The manipulations of nanospheres were provided by means of dielectrophoretic force in SEM. The sensitivity of the mass detector based on the carbon nanowire oscillator was estimated.

  13. Fabrication Of Fiber-Optic Waveguide Coupler

    NASA Technical Reports Server (NTRS)

    Goss, Willis; Nelson, Mark D.; Mclauchlan, John M.

    1989-01-01

    Technique for making four-port, single-mode fiber-optic waveguide couplers requires no critically-precise fabrication operations or open-loop processes. Waveguide couplers analogous to beam-splitter prisms. Essential in many applications that require coherent separation or combination of two waves; for example, for interferometric purposes. Components of optical waveguide coupler held by paraffin on microscope slide while remaining cladding of two optical fibers fused together by arc welding.

  14. Centroid precision and orientation precision of planar localization microscopy.

    PubMed

    McGray, C; Copeland, C R; Stavis, S M; Geist, J

    2016-09-01

    The concept of localization precision, which is essential to localization microscopy, is formally extended from optical point sources to microscopic rigid bodies. Measurement functions are presented to calculate the planar pose and motion of microscopic rigid bodies from localization microscopy data. Physical lower bounds on the associated uncertainties - termed centroid precision and orientation precision - are derived analytically in terms of the characteristics of the optical measurement system and validated numerically by Monte Carlo simulations. The practical utility of these expressions is demonstrated experimentally by an analysis of the motion of a microelectromechanical goniometer indicated by a sparse constellation of fluorescent nanoparticles. Centroid precision and orientation precision, as developed here, are useful concepts due to the generality of the expressions and the widespread interest in localization microscopy for super-resolution imaging and particle tracking.

  15. High-precision camera distortion measurements with a ``calibration harp''

    NASA Astrophysics Data System (ADS)

    Tang, Zhongwei; Grompone von Gioi, Rafael; Monasse, Pascal; Morel, Jean-Michel

    2012-10-01

    This paper addresses the high precision measurement of the distortion of a digital camera from photographs. Traditionally, this distortion is measured from photographs of a flat pattern which contains aligned elements. Nevertheless, it is nearly impossible to fabricate a very flat pattern and to validate its flatness. This fact limits the attainable measurable precisions. In contrast, it is much easier to obtain physically very precise straight lines by tightly stretching good quality strings on a frame. Taking literally "plumb-line methods", we built a "calibration harp" instead of the classic flat patterns to obtain a high precision measurement tool, demonstrably reaching 2/100 pixel precisions. The harp is complemented with the algorithms computing automatically from harp photographs two different and complementary lens distortion measurements. The precision of the method is evaluated on images corrected by state-of-the-art distortion correction algorithms, and by popular software. Three applications are shown: first an objective and reliable measurement of the result of any distortion correction. Second, the harp permits to control state-of-the art global camera calibration algorithms: It permits to select the right distortion model, thus avoiding internal compensation errors inherent to these methods. Third, the method replaces manual procedures in other distortion correction methods, makes them fully automatic, and increases their reliability and precision.

  16. Three dimensional fabrication at small size scales

    PubMed Central

    Leong, Timothy G.; Zarafshar, Aasiyeh M.; Gracias, David H.

    2010-01-01

    Despite the fact that we live in a three-dimensional (3D) world and macroscale engineering is 3D, conventional sub-mm scale engineering is inherently two-dimensional (2D). New fabrication and patterning strategies are needed to enable truly three-dimensionally-engineered structures at small size scales. Here, we review strategies that have been developed over the last two decades that seek to enable such millimeter to nanoscale 3D fabrication and patterning. A focus of this review is the strategy of self-assembly, specifically in a biologically inspired, more deterministic form known as self-folding. Self-folding methods can leverage the strengths of lithography to enable the construction of precisely patterned 3D structures and “smart” components. This self-assembling approach is compared with other 3D fabrication paradigms, and its advantages and disadvantages are discussed. PMID:20349446

  17. Dissolvable microneedle fabrication using piezoelectric dispensing technology.

    PubMed

    Allen, Evin A; O'Mahony, Conor; Cronin, Michael; O'Mahony, Thomas; Moore, Anne C; Crean, Abina M

    2016-03-16

    Dissolvable microneedle (DMN) patches are novel dosage forms for the percutaneous delivery of vaccines. DMN are routinely fabricated by dispensing liquid formulations into microneedle-shaped moulds. The liquid formulation within the mould is then dried to create dissolvable vaccine-loaded microneedles. The precision of the dispensing process is critical to the control of formulation volume loaded into each dissolvable microneedle structure. The dispensing process employed must maintain vaccine integrity. Wetting of mould surfaces by the dispensed formulation is also an important consideration for the fabrication of sharp-tipped DMN. Sharp-tipped DMN are essential for ease of percutaneous administration. In this paper, we demonstrate the ability of a piezoelectric dispensing system to dispense picolitre formulation volumes into PDMS moulds enabling the fabrication of bilayer DMN. The influence of formulation components (trehalose and polyvinyl alcohol (PVA) content) and piezoelectric actuation parameters (voltage, frequency and back pressure) on drop formation is described. The biological integrity of a seasonal influenza vaccine following dispensing was investigated and maintained voltage settings of 30 V but undermined at higher settings, 50 and 80 V. The results demonstrate the capability of piezoelectric dispensing technology to precisely fabricate bilayer DMN. They also highlight the importance of identifying formulation and actuation parameters to ensure controlled droplet formulation and vaccine stabilisation.

  18. Low-resistivity Au /Ni Ohmic contacts to Sb-doped p-type ZnO

    NASA Astrophysics Data System (ADS)

    Mandalapu, L. J.; Yang, Z.; Liu, J. L.

    2007-06-01

    Au /Ni contacts were fabricated on Sb-doped p-type ZnO film, which was grown on n-type Si (100) substrate with a thin undoped ZnO buffer layer by molecular beam epitaxy. As-deposited contacts were rectifying while Ohmic behavior was achieved after thermally annealing the contacts in nitrogen environment. Contact resistance was determined by linear transmission line method and it decreased with the increase of annealing temperature. Low specific contact resistivity of 3.0×10-4Ωcm2 was obtained for sample annealed at 800°C for 60s. Secondary ion mass spectroscopy was used to analyze elemental profiles of the contacts before and after annealing. Zn vacancies created by outdiffusion of Zn are believed to couple with activated Sb atoms to increase the surface hole concentration enabling Ohmic contact formation.

  19. Non-destructive, ultra-low resistance, thermally stable contacts for use on shallow junction InP solar cells

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Fatemi, N. S.; Korenyi-Both, A. L.

    1993-01-01

    Contact formation to InP is plagued by violent metal-semiconductor intermixing that takes place during the contact sintering process. Because of this the InP solar cell cannot be sintered after contact deposition. This results in cell contact resistances that are orders of magnitude higher than those that could be achieved if sintering could be performed in a non-destructive manner. We report here on a truly unique contact system involving Au and Ge, which is easily fabricated, which exhibits extremely low values of contact resistivity, and in which there is virtually no metal-semiconductor interdiffusion, even after extended sintering. We present a description of this contact system and suggest possible mechanisms to explain the observed behavior.

  20. Low resistance Ohmic contact to p-type crystalline silicon via nitrogen-doped copper oxide films

    SciTech Connect

    Zhang, Xinyu Wan, Yimao; Bullock, James; Allen, Thomas; Cuevas, Andres

    2016-08-01

    This work explores the application of transparent nitrogen doped copper oxide (CuO{sub x}:N) films deposited by reactive sputtering to create hole-selective contacts for p-type crystalline silicon (c-Si) solar cells. It is found that CuO{sub x}:N sputtered directly onto crystalline silicon is able to form an Ohmic contact. X-ray photoelectron spectroscopy and Raman spectroscopy measurements are used to characterise the structural and physical properties of the CuO{sub x}:N films. Both the oxygen flow rate and the substrate temperature during deposition have a significant impact on the film composition, as well as on the resulting contact resistivity. After optimization, a low contact resistivity of ∼10 mΩ cm{sup 2} has been established. This result offers significant advantages over conventional contact structures in terms of carrier transport and device fabrication.

  1. Fabrics for aeronautic construction

    NASA Technical Reports Server (NTRS)

    Walen, E D

    1918-01-01

    The Bureau of Standards undertook the investigation of airplane fabrics with the view of finding suitable substitutes for the linen fabrics, and it was decided that the fibers to be considered were cotton, ramie, silk, and hemp. Of these, the cotton fiber was the logical one to be given primary consideration. Report presents the suitability, tensibility and stretching properties of cotton fabric obtained by laboratory tests.

  2. Crimp-Imbalanced Fabrics

    DTIC Science & Technology

    2011-03-30

    invention relates to crimped fabrics which are formed by using various textile architecture such as woven, braided, knitted or other known fabric in which...solution that substantially coats the yarn. The removable coating has a thickness that ensures a proper amount of crimp in the yarn. The tensions in...7 depicts a prior art non-woven cross-ply laminate ; [0037] FIG. 8 depicts a prior art example of balanced crimping in plain-woven fabric; 12

  3. More Questions on Precision Teaching.

    ERIC Educational Resources Information Center

    Raybould, E. C.; Solity, J. E.

    1988-01-01

    Precision teaching can accelerate basic skills progress of special needs children. Issues discussed include using probes as performance tests, charting daily progress, using the charted data to modify teaching methods, determining appropriate age levels, assessing the number of students to be precision taught, and carefully allocating time. (JDD)

  4. Optical Fabrication Nightmares

    NASA Astrophysics Data System (ADS)

    Voras, Robert P.

    1980-09-01

    Optical fabrication nightmares come in a variety of forms. They are generally caused by "toos": too thin, too thick, too large, too small, too many, too few, etc. In practice I believe many optical fabrication problems could be eliminated - or at least minimized -if there were more communication between the designer and the process engineer, up front. However, since the purpose of this paper is to describe difficult items to fabricate and possible solutions for their fabrication, I will get off my soap-box and proceed to my assigned task.

  5. Precision medicine for nurses: 101.

    PubMed

    Lemoine, Colleen

    2014-05-01

    To introduce the key concepts and terms associated with precision medicine and support understanding of future developments in the field by providing an overview and history of precision medicine, related ethical considerations, and nursing implications. Current nursing, medical and basic science literature. Rapid progress in understanding the oncogenic drivers associated with cancer is leading to a shift toward precision medicine, where treatment is based on targeting specific genetic and epigenetic alterations associated with a particular cancer. Nurses will need to embrace the paradigm shift to precision medicine, expend the effort necessary to learn the essential terminology, concepts and principles, and work collaboratively with physician colleagues to best position our patients to maximize the potential that precision medicine can offer. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Solution Synthesis of Atomically Precise Graphene Nanoribbons

    NASA Astrophysics Data System (ADS)

    Shekhirev, Mikhail; Sinitskii, Alexander

    2017-05-01

    Bottom-up fabrication of narrow strips of graphene, also known as graphene nanoribbons or GNRs, is an attractive way to open a bandgap in semimetallic graphene. In this chapter, we review recent progress in solution-based synthesis of GNRs with atomically precise structures. We discuss a variety of atomically precise GNRs and highlight theoretical and practical aspects of their structural design and solution synthesis. These GNRs are typically synthesized through a polymerization of rationally designed molecular precursors followed by a planarization through a cyclodehydrogenation reaction. We discuss various synthetic techniques for polymerization and planarization steps, possible approaches for chemical modification of GNRs, and compare the properties of GNRs that could be achieved by different synthetic methods. We also discuss the importance of the rational design of molecular precursors to avoid isomerization during the synthesis and achieve GNRs that have only one possible structure. Significant attention in this chapter is paid to the methods of material characterization of solution-synthesized GNRs. The chapter is concluded with the discussion of the most significant challenges in the field and the future outlook.

  7. Making Precise Resonators for Mesoscale Vibratory Gyroscopes

    NASA Technical Reports Server (NTRS)

    Yang, Eui-Hyeok

    2004-01-01

    An alternative approach to the design and fabrication of vibratory gyroscopes is founded on the use of fabrication techniques that yield best results in the mesoscopic size range, which is characterized by overall device dimensions of the order of a centimeter. This approach stands in contradistinction to prior approaches in (1) the macroscopic size range (the size range of conventional design and fabrication, characterized by overall device dimensions of many centimeters) and (2) the microscopic size range [the size range of microelectromechanical systems (MEMS), characterized by overall device dimensions of the order of a millimeter or less]. The mesoscale approach offers some of the advantage of the MEMS approach (sizes and power demands smaller than those of the macroscale approach) and some of the advantage of the macroscale approach (the possibility of achieving relative dimensional precision greater than that of the MEMS approach). Relative dimensional precision is a major issue in the operation of a vibratory gyroscope. The heart of a vibratory gyroscope is a mechanical resonator that is required to have a specified symmetry in a plane orthogonal to the axis about which rotation is to be measured. If the resonator could be perfectly symmetrical, then in the absence of rotation, a free vibration of the resonator could remain fixed along any orientation relative to its housing; that is, the gyroscope could exhibit zero drift. In practice, manufacturing imprecision gives rise to some asymmetry in mass, flexural stiffness or dissipation, resulting in a slight drift or beating motion of an initial vibration pattern that cannot be distinguished from rotation. In the mesoscale approach, one exploits the following concepts: For a given amount of dimensional error generated in manufacturing, the asymmetry and hence the rate-of-rotation drift of the gyroscope can be reduced by increasing the scale. The decrease in asymmetry also reduces coupling of vibrations to the

  8. Polymer micromold and fabrication process

    DOEpatents

    Lee, A.P.; Northrup, M.A.; Ahre, P.E.; Dupuy, P.C.

    1997-08-19

    A mold assembly is disclosed with micro-sized features in which the hollow portion thereof is fabricated from a sacrificial mandrel which is surface treated and then coated to form an outer shell. The sacrificial mandrel is then selectively etched away leaving the outer shell as the final product. The sacrificial mandrel is fabricated by a precision lathe, for example, so that when removed by etching the inner or hollow area has diameters as small as 10`s of micros ({micro}m). Varying the inside diameter contours of the mold can be accomplished with specified ramping slopes formed on the outer surface of the sacrificial mandrel, with the inside or hollow section being, for example, 275 {micro}m in length up to 150 {micro}m in diameter within a 6 mm outside diameter (o.d.) mold assembly. The mold assembly itself can serve as a micronozzle or microneedle, and plastic parts, such as microballoons for angioplasty, polymer microparts, and microactuators, etc., may be formed within the mold assembly. 6 figs.

  9. Polymer micromold and fabrication process

    DOEpatents

    Lee, Abraham P.; Northrup, M. Allen; Ahre, Paul E.; Dupuy, Peter C.

    1997-01-01

    A mold assembly with micro-sized features in which the hollow portion thereof is fabricated from a sacrificial mandrel which is surface treated and then coated to form an outer shell. The sacrificial mandrel is then selectively etched away leaving the outer shell as the final product. The sacrificial mandrel is fabricated by a precision lathe, for example, so that when removed by etching the inner or hollow area has diameters as small as 10's of micros (.mu.m). Varying the inside diameter contours of the mold can be accomplished with specified ramping slopes formed on the outer surface of the sacrificial mandrel, with the inside or hollow section being, for example, 275 .mu.m in length up to 150 .mu.m in diameter within a 6 mm outside diameter (o.d.) mold assembly. The mold assembly itself can serve as a micronozzle or microneedle, and plastic parts, such as microballoons for angioplasty, polymer microparts, and microactuators, etc., may be formed within the mold assembly.

  10. Investigation and improvement of the dispenser printing of electrical interconnections for smart fabric applications

    NASA Astrophysics Data System (ADS)

    Ahmed, Z.; Torah, R.; Yang, K.; Beeby, S.; Tudor, J.

    2016-10-01

    Electrical interconnections are essential for the integration of electronic functions in a fabric. These interconnects can be dispenser printed on a fabric; however printing directly on a breathable woven fabric surface is challenging due to the high surface variation and porosity defined by the weave. This paper, for the first time, experimentally shows that fabric surface variation leads to inconsistent printed structures which adversely affects the electrical properties of printed conductive tracks. It investigates a solution of overcoming the fabric surface variation in the form of dispenser printing an interface layer between the conductive ink and the fabric surface. Four dielectric inks DuPont 5018, Electra EFV4/4965, Fabinks-UV-IF-1004 and Fabinks-UV-TC0233 are quantitatively evaluated, as interface materials, in terms of surface consistency, thickness consistency, repeatability, flexibility, thermal stability and the electrical characteristics of conductive tracks printed on them. All four of the evaluated interface materials significantly reduced the fabric surface variation by more than 95% and provided a suitable low variation surface for printing subsequent electronic layers. Conductive tracks, dispenser printed on the four interface materials, produced ∼90% lower electrical resistivity compared to tracks printed directly on the fabric and similar resistivity to dispenser printed tracks on Kapton, a traditional printed electronic substrate. An increased focus on low powered electronics especially for wearables requires the electrical interconnections to dissipate minimum power. The innovative interface layer approach allows fabrication of low resistance electrical interconnections on fabric substrates reducing interconnect power dissipation, making this approach highly suitable for smart fabric applications. Reported details of dispenser printing of interface materials can be used for replicating these results on a range of fabric substrates. The

  11. Fabric Fact & Fiction.

    ERIC Educational Resources Information Center

    Cohen, Andrew

    2001-01-01

    Examines the positive and negative attributes of fabric structures in providing affordable shelter for a variety of multipurpose applications, including temporary or seasonal use. Describes the three basic types of fabric structures: air-supported, frame-supported, and mast-supported. This article focuses on smaller structures of the air- and…

  12. Modeling multilayer woven fabrics

    NASA Astrophysics Data System (ADS)

    Åström, J. A.; Mäkinen, J. P.; Timonen, J.

    2001-07-01

    A numerical algorithm for nonlinear elastic relaxation of a multilayer woven fabric is introduced and tested. The equilibrium solutions are compared with real samples. An excellent result is obtained in spite of two simplifications: Bending stiffness of the fibers and friction between the fibers are both neglected. The numerical simulation is very fast and cost efficient in the search for optimal fabrics.

  13. Smart Fabrics Technology Development

    NASA Technical Reports Server (NTRS)

    Simon, Cory; Potter, Elliott; Potter, Elliott; McCabe, Mary; Baggerman, Clint

    2010-01-01

    Advances in Smart Fabrics technology are enabling an exciting array of new applications for NASA exploration missions, the biomedical community, and consumer electronics. This report summarizes the findings of a brief investigation into the state of the art and potential applications of smart fabrics to address challenges in human spaceflight.

  14. Magnetic fabrics in amphibolites

    NASA Astrophysics Data System (ADS)

    Biedermann, Andrea Regina; Hirt, Ann M.; Kunze, Karsten

    2017-04-01

    Magnetic fabrics are used as indicators for mineral fabrics and thus tectonic settings. In particular, the maximum and minimum magnetic susceptibilities are often taken as representation of the direction of macroscopic lineation and pole to foliation of a rock, respectively. In rocks consisting mainly of amphiboles, the paramagnetic fabric is controlled by the preferential orientation of the amphibole crystals. These crystals normally have their c-axis aligned with lineation, however, the maximum susceptibility is parallel to the crystallographic b-axis, leading to more complicated relationships between the orientations of the magnetic fabric and mineral fabric. Here we describe magnetic fabrics in two amphibolites, both deformed and containing 70 % hornblende. Both amphibolites possess significant magnetic anisotropy with the minimum susceptibility normal to foliation. However, maximum susceptibility and lineation are parallel in one amphibolite, whereas they deviate in the other. Numerical models, which simulate the magnetic anisotropy based on the measured crystallographic preferred orientation (CPO) of hornblende and single crystal anisotropy, can reproduce the observed magnetic fabrics in these samples. Furthermore, synthetic models help explain for which types of CPO the magnetic and mineral lineations are parallel to each other, and when they are not aligned to one another. The results presented here will help in future interpretation of mineral fabrics in amphibole-bearing rocks.

  15. Precision optical navigation guidance system

    NASA Astrophysics Data System (ADS)

    Starodubov, D.; McCormick, K.; Nolan, P.; Johnson, D.; Dellosa, M.; Volfson, L.; Fallahpour, A.; Willner, A.

    2016-05-01

    We present the new precision optical navigation guidance system approach that provides continuous, high quality range and bearing data to fixed wing aircraft during landing approach to an aircraft carrier. The system uses infrared optical communications to measure range between ship and aircraft with accuracy and precision better than 1 meter at ranges more than 7.5 km. The innovative receiver design measures bearing from aircraft to ship with accuracy and precision better than 0.5 mRad. The system provides real-time range and bearing updates to multiple aircraft at rates up to several kHz, and duplex data transmission between ship and aircraft.

  16. Precision Measurements at the ILC

    SciTech Connect

    Nelson, T.K.; /SLAC

    2006-12-06

    With relatively low backgrounds and a well-determined initial state, the proposed International Linear Collider (ILC) would provide a precision complement to the LHC experiments at the energy frontier. Completely and precisely exploring the discoveries of the LHC with such a machine will be critical in understanding the nature of those discoveries and what, if any, new physics they represent. The unique ability to form a complete picture of the Higgs sector is a prime example of the probative power of the ILC and represents a new era in precision physics.

  17. Required precision of mirror surface for solar furnace

    NASA Astrophysics Data System (ADS)

    Shishido, Koro; Shibata, Yukio; Sugiura, Masao; Shoji, Tetsuo

    1995-09-01

    The precision of beautifully finished quadratic surfaced mirrors is about +/- 1/10000th approximately +/- 1/15000th of a radian, performed by the experts, they are called 'Master'. These performances 'beautifully finished' have been done by Master's intuitions or experiences, so it is difficult for mass production of a high quality product. We are trying to reach the Master's territory by using mechanical methods. These are cam and link methods, link-gear-cam method, and glass gauge method. In these methods, the large solar furnace has been produced by cam method, the mirror was ground directly, then mirror precision reached in +/- 1/6000th aprroximately +/- 1/8000th of a radian. In another method, link method, link-gear-cam method, and glass gauge method are used for production of quadratic surfaces master molds, and the glass plates are softened for the quadratic surfaced mirror by these master molds. For example, the precision of the master molds which was fabricated by the cutting machine constructed from the link-gear-cam mechanisms are +/- 1/3000th of a radian, and the precision of master molds which was fabricated by the glass gauge cutting machine are +/- 1/6000th approximately +/- 1/7000th of a radian. Lately, we have considered the quadratic cutting machine constructed from the cylinder type tool for the large diameter of the quadratic surfaces.

  18. Efficient photoelectric converters of ultraviolet radiation based on ZnS and CdS with low-resistivity surface layers

    SciTech Connect

    Bobrenko, Yu. N.; Pavelets, S. Yu. Pavelets, A. M.; Kiselyuk, M. P.; Yaroshenko, N. V.

    2010-08-15

    The formation of thin high- and low-resistivity layers in the space-charge region of Cu{sub 1.8}S-CdS and Cu{sub 1.8}S-ZnS surface-barrier photoconverter structures leads to a considerable increase in photosensitivity and a reduction in the dark tunneling-recombination currents. Highly efficient and stable ultraviolet photoconverters based on CdS and ZnS were obtained, and their electrical and photoelectrical properties were studied. The main operational parameters of the photoconverters are reported.

  19. Branch-line coupler using PDMS and Shieldit Super fabric conductor

    NASA Astrophysics Data System (ADS)

    Babale, S. A.; Rahim, S. K. A.; Jusoh, M.; Zahid, L.

    2017-02-01

    In this paper, a new 3-dB branch-line coupler using PDMS substrate and Shieldit Super fabric conductive material is presented. The Shieldit Super fabric has low resistance less than 0.1/sq. and resulting in good conductivity. Both the simulated and fabricated coupler circuits demonstrated a 3 ± 1 dB fractional bandwidth (FBW) for the coupling as a result of the microstrip-slot created at the ground is in the range of 4.69-7.22 GHz which stands for 42.2%; while the FBW for 90° ± 5°, phase balance is in the range of 5.10-6.94 GHz or 30.70%. Within this range, both the return loss and the isolation are kept below -10 dB.

  20. Precision Instrument and Equipment Repairers.

    ERIC Educational Resources Information Center

    Wyatt, Ian

    2001-01-01

    Explains the job of precision instrument and equipment repairers, who work on cameras, medical equipment, musical instruments, watches and clocks, and industrial measuring devices. Discusses duties, working conditions, employment and earnings, job outlook, and skills and training. (JOW)

  1. Student-Friendly Precision Pendulum.

    ERIC Educational Resources Information Center

    Peters, Randall D.

    1999-01-01

    Provides information to help students easily measure gravitational field strength to a few parts in 10,000, a degree of precision 1-2 orders of magnitude better than can be achieved with the simple pendulum. (CCM)

  2. Watch the Children: Precision Referring

    ERIC Educational Resources Information Center

    Hiltbrunner, Curtis L.; Vasa, Stanley F.

    1974-01-01

    The Precision Referral Form (PRF) is described as a quick, accurate and easy instrument that enables teachers to communicate learning and behavior problems of students to resource or ancillary personnel and to pinpoint students' behaviors. (GW)

  3. Precision engineering: an evolutionary perspective.

    PubMed

    Evans, Chris J

    2012-08-28

    Precision engineering is a relatively new name for a technology with roots going back over a thousand years; those roots span astronomy, metrology, fundamental standards, manufacturing and money-making (literally). Throughout that history, precision engineers have created links across disparate disciplines to generate innovative responses to society's needs and wants. This review combines historical and technological perspectives to illuminate precision engineering's current character and directions. It first provides us a working definition of precision engineering and then reviews the subject's roots. Examples will be given showing the contributions of the technology to society, while simultaneously showing the creative tension between the technological convergence that spurs new directions and the vertical disintegration that optimizes manufacturing economics.

  4. Precision radiotherapy for brain tumors

    PubMed Central

    Yan, Ying; Guo, Zhanwen; Zhang, Haibo; Wang, Ning; Xu, Ying

    2012-01-01

    OBJECTIVE: Precision radiotherapy plays an important role in the management of brain tumors. This study aimed to identify global research trends in precision radiotherapy for brain tumors using a bibliometric analysis of the Web of Science. DATA RETRIEVAL: We performed a bibliometric analysis of data retrievals for precision radiotherapy for brain tumors containing the key words cerebral tumor, brain tumor, intensity-modulated radiotherapy, stereotactic body radiation therapy, stereotactic ablative radiotherapy, imaging-guided radiotherapy, dose-guided radiotherapy, stereotactic brachytherapy, and stereotactic radiotherapy using the Web of Science. SELECTION CRITERIA: Inclusion criteria: (a) peer-reviewed articles on precision radiotherapy for brain tumors which were published and indexed in the Web of Science; (b) type of articles: original research articles and reviews; (c) year of publication: 2002-2011. Exclusion criteria: (a) articles that required manual searching or telephone access; (b) Corrected papers or book chapters. MAIN OUTCOME MEASURES: (1) Annual publication output; (2) distribution according to country; (3) distribution according to institution; (4) top cited publications; (5) distribution according to journals; and (6) comparison of study results on precision radiotherapy for brain tumors. RESULTS: The stereotactic radiotherapy, intensity-modulated radiotherapy, and imaging-guided radiotherapy are three major methods of precision radiotherapy for brain tumors. There were 260 research articles addressing precision radiotherapy for brain tumors found within the Web of Science. The USA published the most papers on precision radiotherapy for brain tumors, followed by Germany and France. European Synchrotron Radiation Facility, German Cancer Research Center and Heidelberg University were the most prolific research institutes for publications on precision radiotherapy for brain tumors. Among the top 13 research institutes publishing in this field, seven

  5. Precision Strike PEO Forum 2006

    DTIC Science & Technology

    2006-07-26

    Requirements, HQ Air Combat Command Predator Precision Weapons Integration and Testing, Mr. Chris Seat, Director, USAF Predator Programs Aircraft Systems Group...Presentation not available for distribution) Predator Precision Weapons Integration and Testing: Chris Seat—Director, USAF Predator Programs Aircraft Systems...2 3 5 6 6 4 5 20 Create the Thunder PLATFORM TARGET GT FLIGHT PATH MAXIMUM ALTITUDE OF AIRCRAFT Airspace Geometries THIS IS THE VOLUME OF AIRSPACE

  6. Precision GPS ephemerides and baselines

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Based on the research, the area of precise ephemerides for GPS satellites, the following observations can be made pertaining to the status and future work needed regarding orbit accuracy. There are several aspects which need to be addressed in discussing determination of precise orbits, such as force models, kinematic models, measurement models, data reduction/estimation methods, etc. Although each one of these aspects was studied at CSR in research efforts, only points pertaining to the force modeling aspect are addressed.

  7. Precision Timed Infrastructure: Design Challenges

    DTIC Science & Technology

    2013-09-19

    recognized the need to precisely model and control time. Mod- elica [30], Simulink [28], and Ptolemy II [12] can precisely model time in both physical and...languages have different ways of expressing computations and timing constraints [5]. For instance, Mod- elica [30], Simulink [28], Giotto [17], Ptolemy ...Languages Intermediate Languages Assembly Languages Modelica Ptolemy IIGiotto and E machine Modelyze PRET Compilation Hide machine dependent details

  8. Fundamental Physics and Precision Measurements

    NASA Astrophysics Data System (ADS)

    Hänsch, T. W.

    2006-11-01

    "Very high precision physics has always appealed to me. The steady improvement in technologies that afford higher and higher precision has been a regular source of excitement and challenge during my career. In science, as in most things, whenever one looks at something more closely, new aspects almost always come into play …" With these word from the book "How the Laser happened", Charles H. Townes expresses a passion for precision that is now shared by many scientists. Masers and lasers have become indispensible tools for precision measurements. During the past few years, the advent of femtosecond laser frequency comb synthesizers has revolutionized the art of directly comparing optical and microwave frequencies. Inspired by the needs of precision laser spectroscopy of the simple hydrogen atom, such frequency combs are now enabling ultra-precise spectroscopy over wide spectral ranges. Recent laboratory experiments are already setting stringent limits for possible slow variations of fundamental constants. Laser frequency combs also provide the long missing clockwork for optical atomic clocks that may ultimately reach a precision of parts in 1018 and beyond. Such tools will open intriguing new opportunities for fundamental experiments including new tests of special and general relativity. In the future, frequency comb techniques may be extended into the extreme ultraviolet and soft xray regime, opening a vast new spectral territory to precision measurements. Frequency combs have also become a key tool for the emerging new field of attosecond science, since they can control the electric field of ultrashort laser pulses on an unprecedented time scale. The biggest surprise in these endeavours would be if we found no surprise.

  9. Recent advancements in optical microstructure fabrication through glass molding process

    NASA Astrophysics Data System (ADS)

    Zhou, Tianfeng; Liu, Xiaohua; Liang, Zhiqiang; Liu, Yang; Xie, Jiaqing; Wang, Xibin

    2017-02-01

    Optical microstructures are increasingly applied in several fields, such as optical systems, precision measurement, and microfluid chips. Microstructures include microgrooves, microprisms, and microlenses. This paper presents an overview of optical microstructure fabrication through glass molding and highlights the applications of optical microstructures in mold fabrication and glass molding. The glass-mold interface friction and adhesion are also discussed. Moreover, the latest advancements in glass molding technologies are detailed, including new mold materials and their fabrication methods, viscoelastic constitutive modeling of glass, and microstructure molding process, as well as ultrasonic vibrationassisted molding technology.

  10. New polymorphous computing fabric.

    SciTech Connect

    Wolinski, C.; Gokhale, M.; McCabe, K. P.

    2002-01-01

    This paper introduces a new polymorphous computing Fabric well suited to DSP and Image Processing and describes its implementation on a Configurable System on a Chip (CSOC). The architecture is highly parameterized and enables customization of the synthesized Fabric to achieve high performance for a specific class of application. For this reason it can be considered to be a generic model for hardware accelerator synthesis from a high level specification. Another important innovation is the Fabric uses a global memory concept, which gives the host processor random access to all the variables and instructions on the Fabric. The Fabric supports different computing models including MIMD, SPMD and systolic flow and permits dynamic reconfiguration. We present a specific implementation of a bank of FIR filters on a Fabric composed of 52 cells on the Altera Excalibur ARM running at 33 MHz. The theoretical performance of this Fabric is 1.8 GMACh. For the FIR application we obtain 1.6 GMAC/s real performance. Some automatic tools have been developed like the tool to provide a host access utility and assembler.

  11. Precision glass molding: an integrative approach for the production of high precision micro-optics

    NASA Astrophysics Data System (ADS)

    Hünten, Martin; Klocke, Fritz; Dambon, Olaf

    2010-02-01

    Miniaturization and integration are the dominating factors for the success of numerous optical devices. Conventional manufacturing processes for the fabrication of precise glass optics by means of grinding and polishing cannot cope the increasing demands in terms of precision, volume and costs. Here, precision glass molding is the enabling technology to meet these demands of the future optical products and applications. Since the market requests further miniaturization and integration of the micro optical components the possession of the entire sequence of processes is absolutely essential. With the accomplished and ongoing developments at the Fraunhofer IPT, the replication of double-sided (a)spherical and (a)cylindrical glass lenses with form accuracies of < 150 nm as well as lens arrays and even freeform optics could be realized. Therefore, a sequence of processes needs to be passed. The FEM-simulation of the molding process which was driven to a point capable to simulate even the molding of freeform optics is the first process step. Further on, new mold design concepts were generated to enable the replication of free formed optics. The research works focusing on the mold manufacturing led to sophisticated grinding process strategies able to realized complex mold geometries such as lens arrays. With regard to the coating of the molds, proceedings were developed assuring a defect free and uniform coating which enables the longevity of the molds and therewith helps reducing the final costs per lens. Thus, the precision glass molding becomes more and more interesting even for highly complex mid volume lots, characteristic for European or US optics manufacturer.

  12. Improvement of the electrochromic response of a low-temperature sintered dye-modified porous electrode using low-resistivity indium tin oxide nanoparticles

    SciTech Connect

    Watanabe, Yuichi Suemori, Kouji; Hoshino, Satoshi

    2016-06-15

    An indium tin oxide (ITO) nanoparticle-based porous electrode sintered at low temperatures was investigated as a transparent electrode for electrochromic displays (ECDs). The electrochromic (EC) response of the dye-modified ITO porous electrode sintered at 150 °C, which exhibited a generally low resistivity, was markedly superior to that of a conventional dye-modified TiO{sub 2} porous electrode sintered at the same temperature. Moreover, the EC characteristics of the dye-modified ITO porous electrode sintered at 150 °C were better than those of the high-temperature (450 °C) sintered conventional dye-modified TiO{sub 2} porous electrode. These improvements in the EC characteristics of the dye-modified ITO porous electrode are attributed to its lower resistivity than that of the TiO{sub 2} porous electrodes. In addition to its sufficiently low resistivity attained under the sintering conditions required for flexible ECD applications, the ITO porous film had superior visible-light transparency and dye adsorption capabilities. We conclude that the process temperature, resistivity, optical transmittance, and dye adsorption capability of the ITO porous electrode make it a promising transparent porous electrode for flexible ECD applications.

  13. Low Resistance Thought Induction Sleep-regulating Technique (TIP3-2) combined with medication for primary insomnia: a randomized controlled trial.

    PubMed

    Wang, Wei-dong; Li, Gui-xia; Hong, Lan; Liu, Yan-jiao; Zhao, Yang; Lin, Ying-na; Wang, Fang; Li, Tao; Yan, Xue; Huang, Yan-ying

    2014-08-01

    Cognitive behavioral therapy for insomnia (CBT-I) is well-validated in the western countries. However, it has not been widely adopted or disseminated in China. One possibility is that therapeutic approaches drawn from traditional Chinese medicine (TCM) will be more widely accepted. This study aimed to evaluate the efficacy of medication in combination with a therapeutic approach drawn from TCM, Low Resistance Thought Induction Sleep-regulating Technique (TIP3-2), for acute treatment of insomnia. A randomized controlled trial was conducted. Ninety primary insomnia patients were randomly assigned to receive TIP3-2 combined with medication (n = 45) or medication only (n = 45) for 4 weeks. Medication consisted of 1-2 mg Estazolam nightly. On the basis of taking Estazolam, TIP3-2 combined with medication group was given Low Resistance Thought Induction Sleep-regulating Technique (TIP3-2) treatment twice a week. Outcomes were assessed with the Pittsburgh sleep quality index (PSQI) and polysomnography (PSG) before and after treatment. Both groups demonstrated significant improvements in the PSQI and polysomnography indices. The TIP3-2+ medication group demonstrated a significant difference between the two groups in PSQI total score, sleep medication use, daytime dysfunction, subjective sleep quality, as well as polysomnography indices of sleep efficiency and awakening times (P < 0.05). Among patients with primary insomnia, the addition of TIP3-2 provided benefits above and beyond the role of medication alone.

  14. Other Fabric Structures

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Architects, engineers and building owners are turning increasingly to fabric structures because of their aesthetic appeal, relatively low initial cost, low maintenance outlays, energy efficiency and good space utilization. Several examples are shown.

  15. Electron Beam Freeform Fabrication

    NASA Image and Video Library

    Electron Beam Freeform Fabrication (EBF3) is a process by which NASA hopes to build metal parts in zero gravity environments. It's a layer-additive process that uses an electron beam and a solid wi...

  16. Speedo Fabric Testing

    NASA Image and Video Library

    Because the physical laws of motion for moving a body through water are the same as moving a vehicle through air, NASA aeronautics experts test the drag effects of different fabrics for Olympic-bou...

  17. Precision Medicine in Gastrointestinal Pathology.

    PubMed

    Wang, David H; Park, Jason Y

    2016-05-01

    -Precision medicine is the promise of individualized therapy and management of patients based on their personal biology. There are now multiple global initiatives to perform whole-genome sequencing on millions of individuals. In the United States, an early program was the Million Veteran Program, and a more recent proposal in 2015 by the president of the United States is the Precision Medicine Initiative. To implement precision medicine in routine oncology care, genetic variants present in tumors need to be matched with effective clinical therapeutics. When we focus on the current state of precision medicine for gastrointestinal malignancies, it becomes apparent that there is a mixed history of success and failure. -To present the current state of precision medicine using gastrointestinal oncology as a model. We will present currently available targeted therapeutics, promising new findings in clinical genomic oncology, remaining quality issues in genomic testing, and emerging oncology clinical trial designs. -Review of the literature including clinical genomic studies on gastrointestinal malignancies, clinical oncology trials on therapeutics targeted to molecular alterations, and emerging clinical oncology study designs. -Translating our ability to sequence thousands of genes into meaningful improvements in patient survival will be the challenge for the next decade.

  18. Fabricated torque shaft

    DOEpatents

    Mashey, Thomas Charles

    2002-01-01

    A fabricated torque shaft is provided that features a bolt-together design to allow vane schedule revisions with minimal hardware cost. The bolt-together design further facilitates on-site vane schedule revisions with parts that are comparatively small. The fabricated torque shaft also accommodates stage schedules that are different one from another in non-linear inter-relationships as well as non-linear schedules for a particular stage of vanes.

  19. Nuclear Fabrication Consortium

    SciTech Connect

    Levesque, Stephen

    2013-04-05

    This report summarizes the activities undertaken by EWI while under contract from the Department of Energy (DOE) Office of Nuclear Energy (NE) for the management and operation of the Nuclear Fabrication Consortium (NFC). The NFC was established by EWI to independently develop, evaluate, and deploy fabrication approaches and data that support the re-establishment of the U.S. nuclear industry: ensuring that the supply chain will be competitive on a global stage, enabling more cost-effective and reliable nuclear power in a carbon constrained environment. The NFC provided a forum for member original equipment manufactures (OEM), fabricators, manufacturers, and materials suppliers to effectively engage with each other and rebuild the capacity of this supply chain by : Identifying and removing impediments to the implementation of new construction and fabrication techniques and approaches for nuclear equipment, including system components and nuclear plants. Providing and facilitating detailed scientific-based studies on new approaches and technologies that will have positive impacts on the cost of building of nuclear plants. Analyzing and disseminating information about future nuclear fabrication technologies and how they could impact the North American and the International Nuclear Marketplace. Facilitating dialog and initiate alignment among fabricators, owners, trade associations, and government agencies. Supporting industry in helping to create a larger qualified nuclear supplier network. Acting as an unbiased technology resource to evaluate, develop, and demonstrate new manufacturing technologies. Creating welder and inspector training programs to help enable the necessary workforce for the upcoming construction work. Serving as a focal point for technology, policy, and politically interested parties to share ideas and concepts associated with fabrication across the nuclear industry. The report the objectives and summaries of the Nuclear Fabrication Consortium

  20. Superabsorbent Multilayer Fabric

    NASA Technical Reports Server (NTRS)

    Coreale, J. V.; Dawn, F. S.

    1982-01-01

    Material contains gel-forming polymer and copolymer that absorb from 70 to 200 times their weight of liquid. Superabsorbent Polymer and Copolymer form gels to bind and retain liquid in multiply fabric. Until reaction between liquid and absorbent masses forms gel, backing layer retains liquids within fabric; also allows material to "breathe." Possible applications include baby diapers, female hygiene napkins, and hospital bedpads. Might also have uses in improvement of dry soil.

  1. Superabsorbent Multilayer Fabric

    NASA Technical Reports Server (NTRS)

    Coreale, J. V.; Dawn, F. S.

    1982-01-01

    Material contains gel-forming polymer and copolymer that absorb from 70 to 200 times their weight of liquid. Superabsorbent Polymer and Copolymer form gels to bind and retain liquid in multiply fabric. Until reaction between liquid and absorbent masses forms gel, backing layer retains liquids within fabric; also allows material to "breathe." Possible applications include baby diapers, female hygiene napkins, and hospital bedpads. Might also have uses in improvement of dry soil.

  2. Precision Casting via Advanced Simulation and Manufacturing

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A two-year program was conducted to develop and commercially implement selected casting manufacturing technologies to enable significant reductions in the costs of castings, increase the complexity and dimensional accuracy of castings, and reduce the development times for delivery of high quality castings. The industry-led R&D project was cost shared with NASA's Aerospace Industry Technology Program (AITP). The Rocketdyne Division of Boeing North American, Inc. served as the team lead with participation from Lockheed Martin, Ford Motor Company, Howmet Corporation, PCC Airfoils, General Electric, UES, Inc., University of Alabama, Auburn University, Robinson, Inc., Aracor, and NASA-LeRC. The technical effort was organized into four distinct tasks. The accomplishments reported herein. Task 1.0 developed advanced simulation technology for core molding. Ford headed up this task. On this program, a specialized core machine was designed and built. Task 2.0 focused on intelligent process control for precision core molding. Howmet led this effort. The primary focus of these experimental efforts was to characterize the process parameters that have a strong impact on dimensional control issues of injection molded cores during their fabrication. Task 3.0 developed and applied rapid prototyping to produce near net shape castings. Rocketdyne was responsible for this task. CAD files were generated using reverse engineering, rapid prototype patterns were fabricated using SLS and SLA, and castings produced and evaluated. Task 4.0 was aimed at developing technology transfer. Rocketdyne coordinated this task. Casting related technology, explored and evaluated in the first three tasks of this program, was implemented into manufacturing processes.

  3. SPEAR3 Gradient Dipole Core Fabrication

    SciTech Connect

    Li, Nanyang

    2003-07-29

    Traditional means of core fabrication are to glue the laminations or weld them to form the yoke structure. These means result in good yoke assemblies for shorter (<0.6m) magnets. However, because of weld distortions or mechanical strength limitations, welding and/or gluing techniques are difficult to gain high mechanical precision for longer cores. The SPEAR3 gradient dipoles are up to 1.45m long and require distortions of <0.05mm. Therefore, the SPEAR3 gradient dipole core design incorporated an assembly technique, originally devised for the PEPII insertion quadrupoles and later adapted for the ALS gradient magnets. This technique involved fabricating a rigid frame for the core, precisely stacking and compressing the laminations using hydraulic jacks and granite surfaces and straight edges, and fixing the laminations in the frame by filling the grooves between the laminations and frame using steel loaded epoxy. Although this technique has been used in the past, it has never been fully described and published. This paper is written to provide a detailed description of the procedure and to present measurement data demonstrating the mechanical precision and stiffness of the resulting product.

  4. Fabric space radiators

    SciTech Connect

    Antoniak, Z.I.; Krotiuk, W.J.; Webb, B.J.; Prater, J.T.; Bates, J.M.

    1988-01-01

    Future Air Force space missions will require thermal radiators that both survive in the hostile space environment and stow away for minimal bulk during launch. Advances in all aspects of radiator design, construction, and analysis will be necessary to enable such future missions. Currently, the best means for obtaining high strength along with flexibility is through structures known as fabrics. The development of new materials and bonding techniques has extended the application range of fabrics into areas traditionally dominated by monolithic and/or metallic structures. Given that even current spacecraft heat rejection considerations tend to dominate spacecraft design and mass, the larger and more complex designs of the future face daunting challenges in thermal control. Ceramic fabrics bonded to ultra-thin metal liners (foils) have the potential of achieving radiator performance levels heretofore unattainable, and of readily matching the advances made in other branches of spacecraft design. The research effort documented here indicates that both pumped loops and heat pipes constructed in ceramic fabrics stand to benefit in multiple ways. Flexibility and low mass are the main advantages exhibited by fabric radiators over conventional metal ones. We feel that fabric radiators have intrinsic merits not possessed by any other radiator design and need to be researched further. 26 refs., 16 figs., 17 tabs.

  5. Single-stripe tunable laser with chirped sampled gratings fabricated by nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Yoshinaga, Hiroyuki; Yanagisawa, Masaki; Kaneko, Toshimitsu; Akiyama, Kan; Tajima, Mikio; Shoji, Daisei; Fujii, Takuya; Shoji, Hajime

    2014-08-01

    The fabrication of diffraction gratings of a chirped sampled gratings distributed reflector (CSG-DR) laser by nanoimprint lithography (NIL) has been demonstrated. The diffraction gratings with highly uniform linewidth and period have been successfully fabricated by the combination of the reverse-tone NIL and precise etching techniques. The CSG-DR laser fabricated by NIL shows a sufficiently wide tuning range of 40 nm as we designed. The results of this study indicate that our fabrication process for the sampled gratings utilizing the NIL technique has a high potential for the fabrication of a CSG-DR laser.

  6. A precision mechanical nerve stimulator

    NASA Technical Reports Server (NTRS)

    Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

    1988-01-01

    An electromechanical device, used to apply and monitor stimulating pulses to a mammalian motor nerve, has been successfully developed at NASA Langley Research Center. Two existing force transducers, a flight skin friction balance and a miniature skin friction balance which were designed for making aerodynamic drag measurements, were modified and incorporated to form this precision instrument. The nerve stimulator is a type one servomechanism capable of applying and monitoring stimulating pulses of 0 to 10 grams with a precision of better than +/- 0.05 grams. Additionally, the device can be independently used to apply stimulating pulses by displacing the nerve from 0 to 0.25 mm with a precision of better than +/- 0.001 mm while measuring the level of the load applied.

  7. Precision cleaning apparatus and method

    DOEpatents

    Schneider, T.W.; Frye, G.C.; Martin, S.J.

    1998-01-13

    A precision cleaning apparatus and method are disclosed. The precision cleaning apparatus includes a cleaning monitor further comprising an acoustic wave cleaning sensor such as a quartz crystal microbalance (QCM), a flexural plate wave (FPW) sensor, a shear horizontal acoustic plate mode (SH--APM) sensor, or a shear horizontal surface acoustic wave (SH--SAW) sensor; and measurement means connectable to the sensor for measuring in-situ one or more electrical response characteristics that vary in response to removal of one or more contaminants from the sensor and a workpiece located adjacent to the sensor during cleaning. Methods are disclosed for precision cleaning of one or more contaminants from a surface of the workpiece by means of the cleaning monitor that determines a state of cleanliness and any residual contamination that may be present after cleaning; and also for determining an effectiveness of a cleaning medium for removing one or more contaminants from a workpiece. 11 figs.

  8. Precision cleaning apparatus and method

    DOEpatents

    Schneider, Thomas W.; Frye, Gregory C.; Martin, Stephen J.

    1998-01-01

    A precision cleaning apparatus and method. The precision cleaning apparatus includes a cleaning monitor further comprising an acoustic wave cleaning sensor such as a quartz crystal microbalance (QCM), a flexural plate wave (FPW) sensor, a shear horizontal acoustic plate mode (SH--APM) sensor, or a shear horizontal surface acoustic wave (SH--SAW) sensor; and measurement means connectable to the sensor for measuring in-situ one or more electrical response characteristics that vary in response to removal of one or more contaminants from the sensor and a workpiece located adjacent to the sensor during cleaning. Methods are disclosed for precision cleaning of one or more contaminants from a surface of the workpiece by means of the cleaning monitor that determines a state of cleanliness and any residual contamination that may be present after cleaning; and also for determining an effectiveness of a cleaning medium for removing one or more contaminants from a workpiece.

  9. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  10. Precise Orbit Determination for ALOS

    NASA Technical Reports Server (NTRS)

    Nakamura, Ryo; Nakamura, Shinichi; Kudo, Nobuo; Katagiri, Seiji

    2007-01-01

    The Advanced Land Observing Satellite (ALOS) has been developed to contribute to the fields of mapping, precise regional land coverage observation, disaster monitoring, and resource surveying. Because the mounted sensors need high geometrical accuracy, precise orbit determination for ALOS is essential for satisfying the mission objectives. So ALOS mounts a GPS receiver and a Laser Reflector (LR) for Satellite Laser Ranging (SLR). This paper deals with the precise orbit determination experiments for ALOS using Global and High Accuracy Trajectory determination System (GUTS) and the evaluation of the orbit determination accuracy by SLR data. The results show that, even though the GPS receiver loses lock of GPS signals more frequently than expected, GPS-based orbit is consistent with SLR-based orbit. And considering the 1 sigma error, orbit determination accuracy of a few decimeters (peak-to-peak) was achieved.

  11. Precision-guaranteed quantum metrology

    NASA Astrophysics Data System (ADS)

    Sugiyama, Takanori

    2015-04-01

    Quantum metrology is a general term for methods to precisely estimate the value of an unknown parameter by actively using quantum resources. In particular, some classes of entangled states can be used to significantly suppress the estimation error. Here we derive a formula for rigorously evaluating an upper bound for the estimation error in a general setting of quantum metrology with arbitrary finite data sets. Unlike in the standard approach, where lower bounds for the error are evaluated in an ideal setting with almost infinite data, our method rigorously guarantees the estimation precision in realistic settings with finite data. We also prove that our upper bound shows the Heisenberg limit scaling whenever the linearized uncertainty, which is a popular benchmark in the standard approach, shows it. As an example, we apply our result to a Ramsey interferometer, and numerically show that the upper bound can exhibit the quantum enhancement of precision for finite data.

  12. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

  13. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  14. Precision Manipulation with Cooperative Robots

    NASA Technical Reports Server (NTRS)

    Stroupe, Ashley; Huntsberger, Terry; Okon, Avi; Aghzarian, Hrand

    2005-01-01

    This work addresses several challenges of cooperative transportThis work addresses several challenges of cooperative transport and precision manipulation. Precision manipulation requires a rigid grasp, which places a hard constraint on the relative rover formation that must be accommodated, even though the rovers cannot directly observe their relative poses. Additionally, rovers must jointly select appropriate actions based on all available sensor information. Lastly, rovers cannot act on independent sensor information, but must fuse information to move jointly; the methods for fusing information must be determined.

  15. Precision Manipulation with Cooperative Robots

    NASA Technical Reports Server (NTRS)

    Stroupe, Ashley; Huntsberger, Terry; Okon, Avi; Aghzarian, Hrand

    2005-01-01

    This work addresses several challenges of cooperative transportThis work addresses several challenges of cooperative transport and precision manipulation. Precision manipulation requires a rigid grasp, which places a hard constraint on the relative rover formation that must be accommodated, even though the rovers cannot directly observe their relative poses. Additionally, rovers must jointly select appropriate actions based on all available sensor information. Lastly, rovers cannot act on independent sensor information, but must fuse information to move jointly; the methods for fusing information must be determined.

  16. PRECISION RADIAL VELOCITIES WITH CSHELL

    SciTech Connect

    Crockett, Christopher J.; Prato, L.; Mahmud, Naved I.; Johns-Krull, Christopher M.; Jaffe, Daniel T.; Beichman, Charles A. E-mail: lprato@lowell.edu E-mail: cmj@rice.edu

    2011-07-10

    Radial velocity (RV) identification of extrasolar planets has historically been dominated by optical surveys. Interest in expanding exoplanet searches to M dwarfs and young stars, however, has motivated a push to improve the precision of near-infrared RV techniques. We present our methodology for achieving 58 m s{sup -1} precision in the K band on the M0 dwarf GJ 281 using the CSHELL spectrograph at the 3 m NASA Infrared Telescope Facility. We also demonstrate our ability to recover the known 4 M{sub JUP} exoplanet Gl 86 b and discuss the implications for success in detecting planets around 1-3 Myr old T Tauri stars.

  17. Universal precision sine bar attachment

    NASA Technical Reports Server (NTRS)

    Mann, Franklin D. (Inventor)

    1989-01-01

    This invention relates to an attachment for a sine bar which can be used to perform measurements during lathe operations or other types of machining operations. The attachment can be used for setting precision angles on vises, dividing heads, rotary tables and angle plates. It can also be used in the inspection of machined parts, when close tolerances are required, and in the layout of precision hardware. The novelty of the invention is believed to reside in a specific versatile sine bar attachment for measuring a variety of angles on a number of different types of equipment.

  18. Precision protection through indirect correlations

    SciTech Connect

    Jin, Yao

    2016-04-15

    The dynamics of the quantum Fisher information of the parameters of the initial atomic state is studied, in the framework of open quantum systems, for a pair of static two-level atoms coupled to a bath of fluctuating vacuum scalar fields. Our results show that the correlations between the two atoms as well as the precision limit in quantum metrology are determined by the separation between the two atoms. Remarkably, when the separation between the two atoms approaches zero, the quantum Fisher information, thus the precision limit of the estimation of the parameters of the initial atomic state will be survived from the vacuum fluctuations after long time evolution.

  19. Precision agriculture and food security.

    PubMed

    Gebbers, Robin; Adamchuk, Viacheslav I

    2010-02-12

    Precision agriculture comprises a set of technologies that combines sensors, information systems, enhanced machinery, and informed management to optimize production by accounting for variability and uncertainties within agricultural systems. Adapting production inputs site-specifically within a field and individually for each animal allows better use of resources to maintain the quality of the environment while improving the sustainability of the food supply. Precision agriculture provides a means to monitor the food production chain and manage both the quantity and quality of agricultural produce.

  20. Behind the Scenes at Berkeley Lab - The Mechanical Fabrication Facility

    SciTech Connect

    Wells, Russell; Chavez, Pete; Davis, Curtis; Bentley, Brian

    2013-05-17

    Part of the Behind the Scenes series at Berkeley Lab, this video highlights the lab's mechanical fabrication facility and its exceptional ability to produce unique tools essential to the lab's scientific mission. Through a combination of skilled craftsmanship and precision equipment, machinists and engineers work with scientists to create exactly what's needed - whether it's measured in microns or meters.

  1. Fabrication of high density, high aspect-ratio polyimide nanofilters.

    SciTech Connect

    Makarova, O.; Tang, C.-M.; Amstutz, P.; Divan, R.; Imre, A.; Mancini, D. C.; Hoffbauer, M.; Williamson, T.

    2009-01-01

    A novel fabrication process produces high porosity polymer nanofilters with smooth, uniform, and straight pores with high aspect ratios. The process utilizes electron beam lithography and energetic neutral atom beam lithography and epitaxy techniques. The method has the potential to produce a new generation of high-precision, very-high-porosity, biocompatible filters with pore sizes down to 100 nm.

  2. Behind the Scenes at Berkeley Lab - The Mechanical Fabrication Facility

    ScienceCinema

    Wells, Russell; Chavez, Pete; Davis, Curtis; Bentley, Brian

    2016-07-12

    Part of the Behind the Scenes series at Berkeley Lab, this video highlights the lab's mechanical fabrication facility and its exceptional ability to produce unique tools essential to the lab's scientific mission. Through a combination of skilled craftsmanship and precision equipment, machinists and engineers work with scientists to create exactly what's needed - whether it's measured in microns or meters.

  3. Precision engineering center. 1988 Annual report, Volume VI

    SciTech Connect

    Dow, T.; Fornaro, R.; Keltie, R.; Paesler, M.

    1988-12-01

    To reverse the downward trend in the balance of trade, American companies must concentrate on increasing research into new products, boosting productivity, and improving manufacturing processes. The Precision Engineering Center at North Carolina State University is a multidisciplinary research and graduate education program dedicated to providing the new technology necessary to respond to this challenge. One extremely demanding manufacturing area is the fabrication and assembly of optical systems. These systems are at the heart of such consumer products as cameras, lenses, copy machines, laser bar-code scanners, VCRs, and compact audio discs - products that the Japanese and other East Asian countries are building dominance. A second critical area is the fabrication of VLSI and ULSI circuits. The tolerances required to produce the next generation of components for such systems have created the need for new approaches - approaches that could either make or break America`s competitive position. This report contains individual reports on research projects grouped into three broad areas: measurement and actuation; real-time control; precision fabrication. Separate abstracts for these articles have been indexed into the energy database.

  4. Microplasma patterning of bonded microchannels using high-precision "injected" electrodes.

    PubMed

    Priest, Craig; Gruner, Philipp J; Szili, Endre J; Al-Bataineh, Sameer A; Bradley, James W; Ralston, John; Steele, David A; Short, Robert D

    2011-02-07

    A rapid, high-precision method for localised plasma-treatment of bonded PDMS microchannels is demonstrated. Patterned electrodes were prepared by injection of molten gallium into preformed microchannel guides. The electrode guides were prepared without any additional fabrication steps compared to conventional microchannel fabrication. Alignment of the "injected" electrodes is precisely controlled by the photomask design, rather than positioning accuracy of alignment tools. Surface modification is detected using a fluorescent dye (Rhodamine B), revealing a well-defined micropattern with regions less than 100 µm along the length of the microchannel.

  5. Impeller Creation at the Fabrication Shop

    NASA Image and Video Library

    1950-10-21

    A mechanic and apprentice work on a wooden impeller in the Fabrication Shop at the NACA Lewis Flight Propulsion Laboratory. The 260-person Fabrication Division created almost all of the equipment and models used at the laboratory. The Technical Services Building, referred to as the “Fab Shop”, contained a number of specialized shops in the 1940s and 1950s. These included a Machine Shop, Sheet Metal Shop, Wood and Pattern Shop, Instrument Shop, Thermocouple Shop, Heat Treating Shop, Metallurgical Laboratory, and Fabrication Office. The Machine Shop fabricated research equipment not commercially available. During World War II these technicians produced high-speed cameras for combustion research, impellers and other supercharger components, and key equipment for the lab’s first supersonic wind tunnel. The Wood and Pattern Shop created everything from control panels and cabinets to aircraft model molds for sheet metal work. The Sheet Metal Shop had the ability to work with 0.01 to 4-inches thick steel plates. The Instrument Shop specialized in miniature parts and instrumentation, while the Thermocouple Shop standardized the installation of pitot tubes and thermocouples. The Metallurgical Laboratory contained a control lab for the Heat Treating Shop and a service lab for the NACA Lewis research divisions. The Heat Treating Shop heated metal parts to optimize their physical properties and contained a Precision Castings Foundry to manufacture equipment made of heat resisting alloys.

  6. FABRICATION AND CHARACTERIZATION OF FAST IGNITION TARGETS

    SciTech Connect

    HILL,D.W; CASTILLO,E; CHEN,K.C; GRANT,S.E; GREENWOOD,A.L; KAAE,J.L; NIKROO,A; PAGUIO,S.P; SHEARER,C; SMITH,JR.,J.N; STEPHENS,R.B; STEINMAN,D.A; WALL,J

    2003-06-01

    OAK-B135 Fast ignition is a novel scheme for achieving laser fusion. A class of these targets involves cone mounted CH shells. The authors have been fabricating such targets with shells with a wide variety of diameters and wall thicknesses for several years at General Atomics. In addition, recently such shells were needed for implosion experiments at Laboratory for Laser Energetics (LLE) that for the first time were required to be gas retentive. Fabrication of these targets requires producing appropriate cones and shells, assembling the targets, and characterization of the assembled targets. The cones are produced using micromachining and plating techniques. The shells are fabricated using the depolymerizable mandrel technique followed by micromachining a hole for the cone. The cone and the shell then need to be assembled properly for gas retention and precisely in order to position the cone tip at the desired position within the shell. Both are critical for the fast ignition experiments. The presence of the cone in the shell creates new challenges in characterization of the assembled targets. Finally, for targets requiring a gas fill, the cone-shell assembly needs to be tested for gas retention and proper strength at the glue joint. This paper presents an overview of the developmental efforts and technical issues addressed during the fabrication of fast ignition targets.

  7. Fabrication and Characterization of Fast Ignition Targets

    SciTech Connect

    Hill, D.W.; Castillo, E.; Chen, K.C.; Grant, S.E.; Greenwood, A.L.; Kaae, J.L.; Nikroo, A.; Paguio, S.P.; Shearer, C.; Smith, J.N. Jr.; Stephens, R.B.; Steinman, D.A.; Wall, J.

    2004-03-15

    Fast ignition is a novel scheme for achieving laser fusion. A class of these targets involves cone mounted CH shells. We have been fabricating such targets with shells with a wide variety of diameters and wall thicknesses for several years at General Atomics. In addition, recently such shells were needed for implosion experiments at Laboratory for Laser Energetics (LLE) that for the first time were required to be gas retentive. Fabrication of these targets requires producing appropriate cones and shells, assembling the targets, and characterization of the assembled targets. The cones are produced using micromachining and plating techniques. The shells are fabricated using the depolymerizable mandrel technique followed by micromachining a hole for the cone. The cone and the shell then need to be assembled properly for gas retention and precisely in order to position the cone tip at the desired position within the shell. Both are critical for the fast ignition experiments. The presence of the cone in the shell creates new challenges in characterization of the assembled targets. Finally, for targets requiring a gas fill, the cone-shell assembly needs to be tested for gas retention and proper strength at the glue joint. This paper presents an overview of the developmental efforts and technical issues addressed during the fabrication of fast ignition targets.

  8. High precision capacitive beam phase probe for KHIMA project

    NASA Astrophysics Data System (ADS)

    Hwang, Ji-Gwang; Yang, Tae-Keun; Forck, Peter

    2016-11-01

    In the medium energy beam transport (MEBT) line of KHIMA project, a high precision beam phase probe monitor is required for a precise tuning of RF phase and amplitude of Radio Frequency Quadrupole (RFQ) accelerator and IH-DTL linac. It is also used for measuring a kinetic energy of ion beam by time-of-flight (TOF) method using two phase probes. The capacitive beam phase probe has been developed. The electromagnetic design of the high precision phase probe was performed to satisfy the phase resolution of 1° (@200 MHz). It was confirmed by the test result using a wire test bench. The measured phase accuracy of the fabricated phase probe is 1.19 ps. The pre-amplifier electronics with the 0.125 ∼ 1.61 GHz broad-band was designed and fabricated for amplifying the signal strength. The results of RF frequency and beam energy measurement using a proton beam from the cyclotron in KIRAMS is presented.

  9. Field precision machining technology of target chamber in ICF lasers

    NASA Astrophysics Data System (ADS)

    Xu, Yuanli; Wu, Wenkai; Shi, Sucun; Duan, Lin; Chen, Gang; Wang, Baoxu; Song, Yugang; Liu, Huilin; Zhu, Mingzhi

    2016-10-01

    In ICF lasers, many independent laser beams are required to be positioned on target with a very high degree of accuracy during a shot. The target chamber provides a precision platform and datum reference for final optics assembly and target collimation and location system. The target chamber consists of shell with welded flanges, reinforced concrete pedestal, and lateral support structure. The field precision machining technology of target chamber in ICF lasers have been developed based on ShenGuangIII (SGIII). The same center of the target chamber is adopted in the process of design, fabrication, and alignment. The technologies of beam collimation and datum reference transformation are developed for the fabrication, positioning and adjustment of target chamber. A supporting and rotating mechanism and a special drilling machine are developed to bore the holes of ports. An adjustment mechanism is designed to accurately position the target chamber. In order to ensure the collimation requirements of the beam leading and focusing and the target positioning, custom-machined spacers are used to accurately correct the alignment error of the ports. Finally, this paper describes the chamber center, orientation, and centering alignment error measurements of SGIII. The measurements show the field precision machining of SGIII target chamber meet its design requirement. These information can be used on similar systems.

  10. Precision glass molding of high-resolution diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans P.; Plöger, Sven; Hermerschmidt, Andreas

    2016-04-01

    The demand of high resolution diffractive optical elements (DOE) is growing. Smaller critical dimensions allow higher deflection angles and can fulfill more demanding requirements, which can only be met by using electron-beam lithography. Replication techniques are more economical, since the high cost of the master can be distributed among a larger number of replicas. The lack of a suitable mold material for precision glass molding has so far prevented an industrial use. Glassy Carbon (GC) offers a high mechanical strength and high thermal strength. No anti-adhesion coatings are required in molding processes. This is clearly an advantage for high resolution, high aspect ratio microstructures, where a coating with a thickness between 10 nm and 200 nm would cause a noticeable rounding of the features. Electron-beam lithography was used to fabricate GC molds with highest precision and feature sizes from 250 nm to 2 μm. The master stamps were used for precision glass molding of a low Tg glass L-BAL42 from OHARA. The profile of the replicated glass is compared to the mold with the help of SEM images. This allows discussion of the max. aspect-ratio and min. feature size. To characterize optical performances, beamsplitting elements are fabricated and their characteristics were investigated, which are in excellent agreement to theory.

  11. Fabrication of thorium bearing carbide fuels

    DOEpatents

    Gutierrez, Rueben L.; Herbst, Richard J.; Johnson, Karl W. R.

    1981-01-01

    Thorium-uranium carbide and thorium-plutonium carbide fuel pellets have been fabricated by the carbothermic reduction process. Temperatures of 1750.degree. C. and 2000.degree. C. were used during the reduction cycle. Sintering temperatures of 1800.degree. C. and 2000.degree. C. were used to prepare fuel pellet densities of 87% and >94% of theoretical, respectively. The process allows the fabrication of kilogram quantities of fuel with good reproducibility of chemicals and phase composition. Methods employing liquid techniques that form carbide microspheres or alloying-techniques which form alloys of thorium-uranium or thorium-plutonium suffer from limitation on the quantities processed of because of criticality concerns and lack of precise control of process conditions, respectively.

  12. Sensor fusion for precision agriculture

    USDA-ARS?s Scientific Manuscript database

    Information-based management of crop production systems known as precision agriculture relies on different sensor technologies aimed at characterization of spatial heterogeneity of a cropping environment. Remote and proximal sensing systems have been deployed to obtain high-resolution data pertainin...

  13. Precision Efficacy Analysis for Regression.

    ERIC Educational Resources Information Center

    Brooks, Gordon P.

    When multiple linear regression is used to develop a prediction model, sample size must be large enough to ensure stable coefficients. If the derivation sample size is inadequate, the model may not predict well for future subjects. The precision efficacy analysis for regression (PEAR) method uses a cross- validity approach to select sample sizes…

  14. Precision orbit computations for Starlette

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Williamson, R. G.

    1976-01-01

    The Starlette satellite, launched in February 1975 by the French Centre National d'Etudes Spatiales, was designed to minimize the effects of nongravitational forces and to obtain the highest possible accuracy for laser range measurements. Analyses of the first four months of global laser tracking data confirmed the stability of the orbit and the precision to which the satellite's position is established.

  15. Drilling Precise Orifices and Slots

    NASA Technical Reports Server (NTRS)

    Richards, C. W.; Seidler, J. E.

    1983-01-01

    Reaction control thrustor injector requires precisely machined orifices and slots. Tooling setup consists of rotary table, numerical control system and torque sensitive drill press. Components used to drill oxidizer orifices. Electric discharge machine drills fuel-feed orifices. Device automates production of identical parts so several are completed in less time than previously.

  16. Precision Teaching ... and All That!

    ERIC Educational Resources Information Center

    Raybould, E. C.; Solity, J. E.

    1988-01-01

    Two proponents of the precision teaching approach to teaching the handicapped discuss such principles as: the problem of partial application of the method; relationship to behaviorism; relationship to experiential learning; and the importance of fluency in task performance, mastery learning, and recordkeeping. (DB)

  17. Spin and precision electroweak physics

    SciTech Connect

    Marciano, W.J.

    1994-12-01

    A perspective on fundamental parameters and precision tests of the Standard Model is given. Weak neutral current reactions are discussed with emphasis on those processes involving (polarized) electrons. The role of electroweak radiative corrections in determining the top quark mass and probing for {open_quotes}new physics{close_quotes} is described.

  18. Precision GPS ephemerides and baselines

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The emphasis of this grant was focused on precision ephemerides for the Global Positioning System (GPS) satellites for geodynamics applications. During the period of this grant, major activities were in the areas of thermal force modeling, numerical integration accuracy improvement for eclipsing satellites, analysis of GIG '91 campaign data, and the Southwest Pacific campaign data analysis.

  19. Spin and precision electroweak physics

    SciTech Connect

    Marciano, W.J.

    1993-12-31

    A perspective on fundamental parameters and precision tests of the Standard Model is given. Weak neutral current reactions are discussed with emphasis on those processes involving (polarized) electrons. The role of electroweak radiative corrections in determining the top quark mass and probing for ``new physics`` is described.

  20. Precision Cleaning - Path to Premier

    NASA Technical Reports Server (NTRS)

    Mackler, Scott E.

    2008-01-01

    ITT Space Systems Division s new Precision Cleaning facility provides critical cleaning and packaging of aerospace flight hardware and optical payloads to meet customer performance requirements. The Precision Cleaning Path to Premier Project was a 2007 capital project and is a key element in the approved Premier Resource Management - Integrated Supply Chain Footprint Optimization Project. Formerly precision cleaning was located offsite in a leased building. A new facility equipped with modern precision cleaning equipment including advanced process analytical technology and improved capabilities was designed and built after outsourcing solutions were investigated and found lacking in ability to meet quality specifications and schedule needs. SSD cleans parts that can range in size from a single threaded fastener all the way up to large composite structures. Materials that can be processed include optics, composites, metals and various high performance coatings. We are required to provide verification to our customers that we have met their particulate and molecular cleanliness requirements and we have that analytical capability in this new facility. The new facility footprint is approximately half the size of the former leased operation and provides double the amount of throughput. Process improvements and new cleaning equipment are projected to increase 1st pass yield from 78% to 98% avoiding $300K+/yr in rework costs. Cost avoidance of $350K/yr will result from elimination of rent, IT services, transportation, and decreased utility costs. Savings due to reduced staff expected to net $4-500K/yr.

  1. Precision Machining Technology. Curriculum Guide.

    ERIC Educational Resources Information Center

    Idaho State Dept. of Education, Boise. Div. of Vocational Education.

    This curriculum guide was developed from a Technical Committee Report prepared with the assistance of industry personnel and containing a Task List which is the basis of the guide. It presents competency-based program standards for courses in precision machining technology and is part of the Idaho Vocational Curriculum Guide Project, a cooperative…

  2. Multi-Step Deep Reactive Ion Etching Fabrication Process for Silicon-Based Terahertz Components

    NASA Technical Reports Server (NTRS)

    Jung-Kubiak, Cecile (Inventor); Reck, Theodore (Inventor); Chattopadhyay, Goutam (Inventor); Perez, Jose Vicente Siles (Inventor); Lin, Robert H. (Inventor); Mehdi, Imran (Inventor); Lee, Choonsup (Inventor); Cooper, Ken B. (Inventor); Peralta, Alejandro (Inventor)

    2016-01-01

    A multi-step silicon etching process has been developed to fabricate silicon-based terahertz (THz) waveguide components. This technique provides precise dimensional control across multiple etch depths with batch processing capabilities. Nonlinear and passive components such as mixers and multipliers waveguides, hybrids, OMTs and twists have been fabricated and integrated into a small silicon package. This fabrication technique enables a wafer-stacking architecture to provide ultra-compact multi-pixel receiver front-ends in the THz range.

  3. Digital transmitter - Simple, yet precise

    NASA Technical Reports Server (NTRS)

    Davarian, F.; Sumida, J.

    1986-01-01

    A transmitter developed for operation at high digital transmission speeds is described. It is a complex system that produces a clean waveform with data rates as high as 1 Mb/s; and its design makes it possible to vary all possible modulation schemes by reprogramming a chip, to vary data-transmission rates with the clock frequency, and to shape pulses without distortion. The design, furthermore, can be adapted to very-large-scale-integration (VLSI) fabrication and mass production. A prototype QPSK residual carrier modulation transmitter was fabricated and tested. The purpose was to create a deep null in the data spectrum to transmit a tone or residual carrier along with the modulation.

  4. Formation of closely packed Cu nanoparticle films by capillary immersion force for preparing low-resistivity Cu films at low temperature

    NASA Astrophysics Data System (ADS)

    Yokoyama, Shun; Motomiya, Kenichi; Takahashi, Hideyuki; Tohji, Kazuyuki

    2016-11-01

    Films made of closely packed Cu nanoparticles (NPs) were obtained by drop casting Cu NP inks. The capillary immersion force exerted during the drying of the inks caused the Cu NPs to attract each other, resulting in closely packed Cu NP films. The apparent density of the films was found to depend on the type of solvent in the ink because the capillary immersion force is affected by the solvent surface tension and dispersibility of Cu NPs in the solvent. The closely packed particulate structure facilitated the sintering of Cu NPs even at low temperature, leading to low-resistivity Cu films. The sintering was also enhanced with a decrease in the size of NPs used. We demonstrated that a closely packed particulate structure using Cu NPs with a mean diameter 61.7 nm showed lower resistivity (7.6 μΩ cm) than a traditionally made Cu NP film (162 μΩ cm) after heat treatment.

  5. Formation of ohmic contacts to low-resistivity Cd{sub 1-x}Mg{sub x}Te alloys for photovolatic applications

    SciTech Connect

    Parfenyuk, O. A. Ilashchuk, M. I.; Ulyanitsky, K. S.

    2008-11-15

    Electrical properties of the Cd{sub 1-x}Mg{sub x} Te alloys of various composition (0.1 {<=} x {<=} 0.3) are studied. It is established that at x = 0.1, a low-resistivity p-type material with parameters close to undoped CdTe is formed. A feature of the Cd{sub 0.9}Mg{sub 0.1} Te crystals is that, during deposition of Cu on their surface from a saturated CuSO{sub 4} solution, ohmic contact is formed, the characteristics of which do not worsen in a wide temperature range (80-300 K). The study of characteristics with and without illumination of the Cu/p-Cd{sub 0.9}Mg{sub 0.1}Te/n-Cd{sub 0.9}Mg{sub 0.1}Te/In structures have shown that they are promising as photoconverters of solar radiation.

  6. Fabrication of PDMS architecture

    NASA Astrophysics Data System (ADS)

    Adam, Tijjani; Hashim, U.

    2017-03-01

    The study report novel, yet simple and flexible fabrication method for micro channel patterning PDMS thin mold on glass surfaces, the method allows microstructures with critical dimensions to be formed using PDMS. Micro channel production is a two-step process. First, soft photolithography methods are implemented to fabricate a reusable mold. The mold is then used to create the micro channel, which consists of SU8, PDMS and glass. The micro channel design was performed using AutoCAD and the fabrication begins by creating a replicable mold. The mold is created on a glass slide. by spin-coating speed between 500 to 1250rpm with an acceleration of 100 rpm/s for 100 and 15 second ramp up and down speed respectively. Channel flow rate based on concentration were measured by analyzing the recorded flow profiles which was collected from the high powered microscope at. 80µ, 70µm, 50µm for inlet channel 1, 2, 3 respectively the channel flow were compared for flow efficiency at different concentrations and Re. Thus, the simplicity of device structure and fabrication makes it feasible to miniaturize it for the development of point-of-care kits, facilitating its use in both clinical and non-clinical environments. With its simple geometric structure and potential for mass commercial fabrication, the device can be developed to become a portable photo detection sensor that can be use for both environmental and diagnostic application.

  7. Design, fabrication and control of soft robots.

    PubMed

    Rus, Daniela; Tolley, Michael T

    2015-05-28

    Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.

  8. Design, fabrication and control of soft robots

    NASA Astrophysics Data System (ADS)

    Rus, Daniela; Tolley, Michael T.

    2015-05-01

    Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.

  9. Hydrogen ion-implantation induced low resistive layer in KNbO3 bulk single crystal: Evaluation by elastic recoil detection analysis

    NASA Astrophysics Data System (ADS)

    Shinkawa, A.; Shibasaki, Y.; Nishimura, T.; Tanuma, C.; Kuriyama, K.

    2016-03-01

    Origins of low resistivity in H-ion implanted KNbO3 bulk single crystals are studied by elastic recoil detection analysis (ERDA) and Van der Pauw methods. The H-ion implantation (peak ion fluence: 5.0 × 1015 cm-2) into KNbO3 is performed using a 500 keV implanter. The sheet resistance decreases from ∼108 Ω/□ for an un-implanted KNbO3 sample to 2.33 × 105 Ω/□ for as-implanted, 2.29 × 105 Ω/□ for 100 °C annealed, and 4.25 × 105 Ω/□ for 150 °C annealed samples, respectively. The ERDA experiment using the 1.5 MeV-4He+ beam can evaluate hydrogen from the surface to around 60 nm. The hydrogen concentration near the surface estimated using the 1.5 MeV helium beam is 5.1 × 1014 cm-2 for un-implanted KNbO3 sample, 5.6 × 1014 cm-2 for as-implanted, 3.4 × 1014 cm-2 for 150 °C annealed samples, respectively, indicating that a part of hydrogen is diffused out by annealing. The low resistive layer induced in H-ion implanted KNbO3 suggests the existence of a shallow energy level related to the complex defect consisting of hydrogen interstitial and the proton induced defect such as oxygen vacancy.

  10. Beyond precision surgery: Molecularly motivated precision care for gastric cancer.

    PubMed

    Choi, Y Y; Cheong, J-H

    2017-03-01

    Gastric cancer is one of the leading causes of cancer-related deaths worldwide. Despite the high disease prevalence, gastric cancer research has not gained much attention. Recently, genome-scale technology has made it possible to explore the characteristics of gastric cancer at the molecular level. Accordingly, gastric cancer can be classified into molecular subtypes that convey more detailed information of tumor than histopathological characteristics, and these subtypes are associated with clinical outcomes. Furthermore, this molecular knowledge helps to identify new actionable targets and develop novel therapeutic strategies. To advance the concept of precision patient care in the clinic, patient-derived xenograft (PDX) models have recently been developed. PDX models not only represent histology and genomic features, but also predict responsiveness to investigational drugs in patient tumors. Molecularly curated PDX cohorts will be instrumental in hypothesis generation, biomarker discovery, and drug screening and testing in proof-of-concept preclinical trials for precision therapy. In the era of precision medicine, molecularly tailored therapeutic strategies should be individualized for cancer patients. To improve the overall clinical outcome, a multimodal approach is indispensable for advanced cancer patients. Careful, oncological principle-based surgery, combined with a molecularly guided multidisciplinary approach, will open new horizons in surgical oncology.

  11. Comparisons of precision of fit between cast and CNC-milled titanium implant frameworks for the edentulous mandible.

    PubMed

    Ortorp, Anders; Jemt, Torsten; Bäck, Tomas; Jälevik, Tord

    2003-01-01

    The purpose of this study was to investigate and compare the precision of fabrication in repeatqdly produced computer numeric controlled (CNC)-milled frameworks with consventional castings, and to analyze the distortion from application of different veneering materials. Twenty identical titanium frameworks were fabricated by means of a CNC milling technique for the same master model. Five conventional frameworks were cast as a control group to the same model. The frames were measured with regard to fit in a coordinate measuring machine linked to a computer. Measurements were made during different stages of handling of the titanium framework, and after veneering materials had been applied. The CNC frameworks showed a statistically better fit and precision of fabrication compared to conventional castings (P < .05). The application of veneering material did not statistically affect the fit of the titanium frameworks (P > .05). It is possible to fabricate implant-supported frameworks by means of the present CNC technique with a very high precision and repeatability.

  12. 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.

  13. Ultra-precision molding of chalcogenide glass aspherical lens

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Wang, Zhibin; Zhang, Yunlong; Su, Ying; Guo, Rui; Xu, Zengqi; Liu, Xuanmin

    2016-10-01

    With the development of infrared optical systems in military and civil areas, chalcogenide glass aspherical lens possess some advantages, such as large infrared transmission, good thermal stability performance and image quality. Aspherical lens using chalcogenide glass can satisfy the requirements of modern infrared optical systems. Therefore, precision manufacturing of chalcogenide glass aspheric has received more and more attention. The molding technology of chalcogenide glass aspheric has become a research hotspot, because it can achieve mass and low cost manufacturing. The article of molding technology is focusing on a kind of chalcogenide glass aspherical lens. We report on design and fabrication of the mold that through simulation analysis of molding. Finally, through molding test, the fabrication of mold's surface and parameters of molding has been optimized, ensuring the indicators of chalcogenide glass aspherical lens meet the requirements.

  14. Other Fabric Structures

    NASA Technical Reports Server (NTRS)

    1985-01-01

    There are two kinds of fabric structures - tension, supported by cables and pylons, and those supported by air pressure within an enclosed fabric envelope. They are becoming increasingly popular with architects, engineers, etc., because of their aesthetic appeal, low cost and maintenance, energy efficiency and good space utilization. The Structo-Fab roof weighs only 1/30 as much as a conventional roof of that size. Giant fans are used to blow air into the envelope between the roof's outer membrane and its inner liner automatically maintaining the pressure differential necessary for roof rigidity.

  15. Fabrication of multilayer nanowires

    SciTech Connect

    Kaur, Jasveer Singh, Avtar; Kumar, Davinder; Thakur, Anup; Kaur, Raminder

    2016-05-06

    Multilayer nanowires were fabricated by potentiostate ectrodeposition template synthesis method into the pores of polycarbonate membrane. In present work layer by layer deposition of two different metals Ni and Cu in polycarbonate membrane having pore size of 600 nm were carried out. It is found that the growth of nanowires is not constant, it varies with deposition time. Scanning electron microscopy (SEM) is used to study the morphology of fabricated multilayer nanowires. An energy dispersive X-ray spectroscopy (EDS) results confirm the composition of multilayer nanowires. The result shows that multilayer nanowires formed is dense.

  16. Thermal Skin fabrication technology

    NASA Technical Reports Server (NTRS)

    Milam, T. B.

    1972-01-01

    Advanced fabrication techniques applicable to Thermal Skin structures were investigated, including: (1) chemical machining; (2) braze bonding; (3) diffusion bonding; and (4) electron beam welding. Materials investigated were nickel and nickel alloys. Sample Thermal Skin panels were manufactured using the advanced fabrication techniques studied and were structurally tested. Results of the program included: (1) development of improved chemical machining processes for nickel and several nickel alloys; (2) identification of design geometry limits; (3) identification of diffusion bonding requirements; (4) development of a unique diffusion bonding tool; (5) identification of electron beam welding limits; and (6) identification of structural properties of Thermal Skin material.

  17. In Situ Fabrication Technologies

    NASA Technical Reports Server (NTRS)

    Rolin, Terry D.; Hammond, Monica

    2005-01-01

    A manufacturing system is described that is internal to controlled cabin environments which will produce functional parts to net shape with sufficient tolerance, strength and integrity to meet application specific needs such as CEV ECLS components, robotic arm or rover components, EVA suit items, unforeseen tools, conformal repair patches, and habitat fittings among others. Except for start-up and shut-down, fabrication will be automatic without crew intervention under nominal scenarios. Off-nominal scenarios may require crew and/or Earth control intervention. System will have the ability to fabricate using both provisioned feedstock materials and feedstock refined from in situ regolith.

  18. [Micro fabricated enzyme battery].

    PubMed

    Sasaki, S; Karube, I

    1996-10-01

    Although various work has been done in the field of implantable micro actuators such as artificial organs and micro surgery robots, a suitable electric power supply for these is yet to be developed. For this purpose a micro fabricated enzyme fuel cell was developed which uses glucose contained in the human body as a fuel. In order to obtain enough voltage each cell was formed as part of a serial array on a silicon wafer. Glucose solution enters the cells by a capillary effect. In this article fuel cells already developed using biocatalysts are described, and the future possibility of a micro fabricated enzyme battery is discussed.

  19. Precision electroweak physics at LEP

    SciTech Connect

    Mannelli, M.

    1994-12-01

    Copious event statistics, a precise understanding of the LEP energy scale, and a favorable experimental situation at the Z{sup 0} resonance have allowed the LEP experiments to provide both dramatic confirmation of the Standard Model of strong and electroweak interactions and to place substantially improved constraints on the parameters of the model. The author concentrates on those measurements relevant to the electroweak sector. It will be seen that the precision of these measurements probes sensitively the structure of the Standard Model at the one-loop level, where the calculation of the observables measured at LEP is affected by the value chosen for the top quark mass. One finds that the LEP measurements are consistent with the Standard Model, but only if the mass of the top quark is measured to be within a restricted range of about 20 GeV.

  20. Touch Precision Modulates Visual Bias.

    PubMed

    Misceo, Giovanni F; Jones, Maurice D

    2017-08-29

    The sensory precision hypothesis holds that different seen and felt cues about the size of an object resolve themselves in favor of the more reliable modality. To examine this precision hypothesis, 60 college students were asked to look at one size while manually exploring another unseen size either with their bare fingers or, to lessen the reliability of touch, with their fingers sleeved in rigid tubes. Afterwards, the participants estimated either the seen size or the felt size by finding a match from a visual display of various sizes. Results showed that the seen size biased the estimates of the felt size when the reliability of touch decreased. This finding supports the interaction between touch reliability and visual bias predicted by statistically optimal models of sensory integration.

  1. High Precision 2-D Grating Groove Density Measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Ningxiao; McEntaffer, Randall; Tedesco, Ross

    2017-08-01

    Our research group at Penn State University is working on producing X-ray reflection gratings with high spectral resolving power and high diffraction efficiency. To estimate our fabrication accuracy, we apply a precise 2-D grating groove density measurement to plot groove density distributions of gratings on 6-inch wafers. In addition to plotting a fixed groove density distribution, this method is also sensitive to measuring the variation of the groove density simultaneously. This system can reach a measuring accuracy (ΔN/N) of 10-3. Here we present this groove density measurement and some applications.

  2. Precision linear ramp function generator

    DOEpatents

    Jatko, W. Bruce; McNeilly, David R.; Thacker, Louis H.

    1986-01-01

    A ramp function generator is provided which produces a precise linear ramp unction which is repeatable and highly stable. A derivative feedback loop is used to stabilize the output of an integrator in the forward loop and control the ramp rate. The ramp may be started from a selected baseline voltage level and the desired ramp rate is selected by applying an appropriate constant voltage to the input of the integrator.

  3. Precision linear ramp function generator

    DOEpatents

    Jatko, W.B.; McNeilly, D.R.; Thacker, L.H.

    1984-08-01

    A ramp function generator is provided which produces a precise linear ramp function which is repeatable and highly stable. A derivative feedback loop is used to stabilize the output of an integrator in the forward loop and control the ramp rate. The ramp may be started from a selected baseline voltage level and the desired ramp rate is selected by applying an appropriate constant voltage to the input of the integrator.

  4. High precision triangular waveform generator

    DOEpatents

    Mueller, Theodore R.

    1983-01-01

    An ultra-linear ramp generator having separately programmable ascending and descending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.

  5. Green Solvents for Precision Cleaning

    NASA Technical Reports Server (NTRS)

    Grandelli, Heather; Maloney, Phillip; DeVor, Robert; Surma, Jan; Hintze, Paul

    2013-01-01

    Aerospace machinery used in liquid oxygen (LOX) fuel systems must be precision cleaned to achieve a very low level of non-volatile residue (< 1 mg0.1 m2), especially flammable residue. Traditionally chlorofluorocarbons (CFCs) have been used in the precision cleaning of LOX systems, specifically CFC 113 (C2Cl3F3). CFCs have been known to cause the depletion of ozone and in 1987, were banned by the Montreal Protocol due to health, safety and environmental concerns. This has now led to the development of new processes in the precision cleaning of aerospace components. An ideal solvent-replacement is non-flammable, environmentally benign, non-corrosive, inexpensive, effective and evaporates completely, leaving no residue. Highlighted is a green precision cleaning process, which is contaminant removal using supercritical carbon dioxide as the environmentally benign solvent. In this process, the contaminant is dissolved in carbon dioxide, and the parts are recovered at the end of the cleaning process completely dry and ready for use. Typical contaminants of aerospace components include hydrocarbon greases, hydraulic fluids, silicone fluids and greases, fluorocarbon fluids and greases and fingerprint oil. Metallic aerospace components range from small nuts and bolts to much larger parts, such as butterfly valves 18 in diameter. A fluorinated grease, Krytox, is investigated as a model contaminant in these preliminary studies, and aluminum coupons are employed as a model aerospace component. Preliminary studies are presented in which the experimental parameters are optimized for removal of Krytox from aluminum coupons in a stirred-batch process. The experimental conditions investigated are temperature, pressure, exposure time and impeller speed. Temperatures of 308 - 423 K, pressures in the range of 8.3 - 41.4 MPa, exposure times between 5 - 60 min and impeller speeds of 0 - 1000 rpm were investigated. Preliminary results showed up to 86 cleaning efficiency with the

  6. Method for grinding precision components

    SciTech Connect

    Ramanath, S.; Kuo, S.Y.; Williston, W.H.; Buljan, S.T.

    2000-02-01

    A method for precision cylindrical grinding of hard brittle materials, such as ceramics or glass and composites comprising ceramics or glass, provides material removal rates as high as 19--380 cm{sup 3}/min/cm. The abrasive tools used in the method comprise a strong, light weight wheel core bonded to a continuous rim of abrasive segments containing superabrasive grain in a dense metal bond matrix.

  7. Precision Atomic Beam Laser Spectroscopy

    DTIC Science & Technology

    1999-02-20

    postdoctoral, and visiting faculty researchers. The organizing principles of our work are to enhance the coherence and general utility of laser sources by... utilizing some million atoms, namely -1000:1. The optimum servo control of the laser using this signal could evidently produce a laser linewidth in the...Lett. 22,184-186 (1997), P. Dube, M. D. Levenson, and J. L. Hall. 10. "Real-time precision refractometry : new approaches," Appl. Opt. 36,1223- 1234

  8. Precision Medicine Comes to Thyroidology.

    PubMed

    Ladenson, Paul W

    2016-03-01

    The broad spectrum of thyroid disease severity--from subclinical hypothyroidism to myxedema coma, subclinical thyrotoxicosis to thyroid storm, and microscopic papillary to anaplastic cancers--has always demanded that clinicians individualize their management of thyroid patients. Deepening knowledge of thyroid pathophysiology along with advances in diagnostic, prognostic, and therapeutic technologies applicable to thyroid diseases position this field to ride the wave of precision medicine in the decade ahead.

  9. Method for grinding precision components

    DOEpatents

    Ramanath, Srinivasan; Kuo, Shih Yee; Williston, William H.; Buljan, Sergej-Tomislav

    2000-01-01

    A method for precision cylindrical grinding of hard brittle materials, such as ceramics or glass and composites comprising ceramics or glass, provides material removal rates as high as 19-380 cm.sup.3 /min/cm. The abrasive tools used in the method comprise a strong, light weight wheel core bonded to a continuous rim of abrasive segments containing superabrasive grain in a dense metal bond matrix.

  10. DC-driven thermoelectric Peltier device for precise DNA amplification

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Shigeo; Suzuki, Tadzunu; Inoue, Kazuhito; Azumi, Yoshitaka

    2015-05-01

    Using a DC-driven Peltier device, we fabricated a DNA amplification system [polymerase chain reaction (PCR) system] with the aim of increasing its speed and precision. The Peltier device had a well block sandwiched by Bi2Se0.37Te2.36 as an N-type thermoelectric material and Bi0.59Sb1.30Te3 as a P-type material. The well block was directly controlled by the electric current, leading to a high thermal response. Using the Peltier device with the well block, we performed thermal cycles of a PCR, and we demonstrated that our PCR system produces a smaller amount of nonspecific products for the genome DNA (gDNA) of Arabidopsis thaliana, leading to a more precise DNA amplification system.

  11. Novel TMA telescope based on ultra precise metal mirrors

    NASA Astrophysics Data System (ADS)

    Risse, S.; Gebhardt, A.; Damm, C.; Peschel, T.; Stöckl, W.; Feigl, T.; Kirschstein, S.; Eberhardt, R.; Kaiser, N.; Tünnermann, A.

    2008-07-01

    Modern telescopes for space applications use complex optical elements like aspheres or freeforms. For the multispectral pushbroom scanner for spaceborne Earth remote sensing the Jena-Optonik GmbH has developed a Jena-Spaceborne- Scanner JSS product line. The optic of JSS-56 imager is realised by a Three-Mirror-Anastigmat (TMA) telescope designed in aluminium [1]. For brilliant pictures, mirrors with high shape accuracy and very smooth surfaces are required. The combination of precise diamond turning and post polishing techniques enables the classical infrared application for the visible and ultra-violet range. A wide variety of complex mirror shapes are feasible. A special new solution for lightweight design was applied. Ultra precise metal mirrors with aspherical surface are developed at the Fraunhofer IOF from design to system integration. This paper summarizes technologies and results for design, fabrication and surface finish of ultra lightweight aspherical metal mirrors for novel TMA telescopes.

  12. Precision optical metrology without lasers

    NASA Astrophysics Data System (ADS)

    Bergmann, Ralf B.; Burke, Jan; Falldorf, Claas

    2015-07-01

    Optical metrology is a key technique when it comes to precise and fast measurement with a resolution down to the micrometer or even nanometer regime. The choice of a particular optical metrology technique and the quality of results depends on sample parameters such as size, geometry and surface roughness as well as user requirements such as resolution, measurement time and robustness. Interferometry-based techniques are well known for their low measurement uncertainty in the nm range, but usually require careful isolation against vibration and a laser source that often needs shielding for reasons of eye-safety. In this paper, we concentrate on high precision optical metrology without lasers by using the gradient based measurement technique of deflectometry and the finite difference based technique of shear interferometry. Careful calibration of deflectometry systems allows one to investigate virtually all kinds of reflecting surfaces including aspheres or free-form surfaces with measurement uncertainties below the μm level. Computational Shear Interferometry (CoSI) allows us to combine interferometric accuracy and the possibility to use cheap and eye-safe low-brilliance light sources such as e.g. fiber coupled LEDs or even liquid crystal displays. We use CoSI e.g. for quantitative phase contrast imaging in microscopy. We highlight the advantages of both methods, discuss their transfer functions and present results on the precision of both techniques.

  13. Do not let precision medicine be kidnapped.

    PubMed

    Yang, Zhiping

    2015-12-01

    Obama’s precision medicine initiative made the medical community boil over after the initiative’s release. Precision medicine has been advocated by the majority of scientists and doctors. However, some experts have questioned this concept. This article does not oppose precision medicine. However, the incentive of vigorously promoting precision medicine at present is a concern.

  14. Lithographic fabrication of nanoapertures

    DOEpatents

    Fleming, James G.

    2003-01-01

    A new class of silicon-based lithographically defined nanoapertures and processes for their fabrication using conventional silicon microprocessing technology have been invented. The new ability to create and control such structures should significantly extend our ability to design and implement chemically selective devices and processes.

  15. Fabricating Structural Beams

    NASA Technical Reports Server (NTRS)

    Engler, E. E.; Ehl, J.; Muench, W.; Morfin, H.; Huber, J.; Braun, R.; Marx, W.; Alberi, A.; Romaneck, R.; Johnson, C.; Giannuzzi, O.; Weyhreter, A.

    1982-01-01

    Automatic machine described in new report has demonstrated on Earth feasibility of machine fabricating beams for huge structures in space. Such structures include solar mirrors, radiometer reflectors, microwave power transmitters, solar-thermal power generators, and solar photoelectric generators, ranging in size from few hundred meters long to tens of kilometers long.

  16. Molecular transport through capillaries made with atomic-scale precision

    NASA Astrophysics Data System (ADS)

    Radha, B.; Esfandiar, A.; Wang, F. C.; Rooney, A. P.; Gopinadhan, K.; Keerthi, A.; Mishchenko, A.; Janardanan, A.; Blake, P.; Fumagalli, L.; Lozada-Hidalgo, M.; Garaj, S.; Haigh, S. J.; Grigorieva, I. V.; Wu, H. A.; Geim, A. K.

    2016-10-01

    Nanometre-scale pores and capillaries have long been studied because of their importance in many natural phenomena and their use in numerous applications. A more recent development is the ability to fabricate artificial capillaries with nanometre dimensions, which has enabled new research on molecular transport and led to the emergence of nanofluidics. But surface roughness in particular makes it challenging to produce capillaries with precisely controlled dimensions at this spatial scale. Here we report the fabrication of narrow and smooth capillaries through van der Waals assembly, with atomically flat sheets at the top and bottom separated by spacers made of two-dimensional crystals with a precisely controlled number of layers. We use graphene and its multilayers as archetypal two-dimensional materials to demonstrate this technology, which produces structures that can be viewed as if individual atomic planes had been removed from a bulk crystal to leave behind flat voids of a height chosen with atomic-scale precision. Water transport through the channels, ranging in height from one to several dozen atomic planes, is characterized by unexpectedly fast flow (up to 1 metre per second) that we attribute to high capillary pressures (about 1,000 bar) and large slip lengths. For channels that accommodate only a few layers of water, the flow exhibits a marked enhancement that we associate with an increased structural order in nanoconfined water. Our work opens up an avenue to making capillaries and cavities with sizes tunable to ångström precision, and with permeation properties further controlled through a wide choice of atomically flat materials available for channel walls.

  17. Dyeing fabrics with metals

    NASA Astrophysics Data System (ADS)

    Kalivas, Georgia

    2002-06-01

    Traditionally, in textile dyeing, metals have been used as mordants or to improve the color produced by a natural or synthetic dye. In biomedical research and clinical diagnostics gold colloids are used as sensitive signals to detect the presence of pathogens. It has been observed that when metals are finely divided, a distinct color may result that is different from the color of the metal in bulk. For example, when gold is finely divided it may appear black, ruby or purple. This can be seen in biomedical research when gold colloids are reduced to micro-particles. Bright color signals are produced by few nanometer-sized particles. Dr. William Todd, a researcher in the Department of Veterinary Science at the Louisiana State University, developed a method of dyeing fabrics with metals. By using a reagent to bond the metal particles deep into the textile fibers and actually making the metal a part of the chemistry of the fiber. The chemicals of the fabric influence the resulting color. The combination of the element itself, the size of the particle, the chemical nature of the particle and the interaction of the metal with the chemistry of the fabric determine the actual hue. By using different elements, reagents, textiles and solvents a broad range of reproducible colors and tones can be created. Metals can also be combined into alloys, which will produce a variety of colors. The students of the ISCC chapter at the Fashion Institute of Technology dyed fabric using Dr. Todd's method and created a presentation of the results. They also did a demonstration of dyeing fabrics with metals.

  18. Fabricating PFPE Membranes for Capillary Electrophoresis

    NASA Technical Reports Server (NTRS)

    Lee, Michael C.; Willis, Peter A.; Greer, Frank; Rolland, Jason

    2009-01-01

    A process has been developed for fabricating perfluoropolyether (PFPE) membranes that contain microscopic holes of precise sizes at precise locations. The membranes are to be incorporated into laboratory-on-a-chip microfluidic devices to be used in performing capillary electrophoresis. The present process is a modified version of part of the process, described in the immediately preceding article, that includes a step in which a liquid PFPE layer is cured into solid (membrane) form by use of ultraviolet light. In the present process, one exploits the fact that by masking some locations to prevent exposure to ultraviolet light, one can prevent curing of the PFPE in those locations. The uncured PFPE can be washed away from those locations in the subsequent release and cleaning steps. Thus, holes are formed in the membrane in those locations. The most straightforward way to implement the modification is to use, during the ultraviolet-curing step, an ultraviolet photomask similar to the photomasks used in fabricating microelectronic devices. In lieu of such a photomask, one could use a mask made of any patternable ultraviolet-absorbing material (for example, an ink or a photoresist).

  19. Precision Measurement Of Corneal Topography

    NASA Astrophysics Data System (ADS)

    Yoder, Paul R.; Macri, Timothy F.; Telfair, William B.; Bennett, Peter S.; Martin, Clifford A.; Warner, John W.

    1989-05-01

    We describe a new electro-optical device being developed to provide precise measurements of the three-dimensional topography of the human cornea. This device, called a digital keratoscope, is intended primarily for use in preparing for and determining the effect of corneal surgery procedures such as laser refractive keratectomy, radial keratotomy or corneal transplant on the refractive power of the cornea. It also may serve as an aid in prescribing contact lenses. The basic design features of the hardware and of the associated computer software are discussed, the means for alignment and calibration are described and typical results are given.

  20. RNA Bioinformatics for Precision Medicine.

    PubMed

    Chen, Jiajia; Shen, Bairong

    2016-01-01

    The high-throughput transcriptomic data generated by deep sequencing technologies urgently require bioinformatics methods for proper data visualization, analysis, storage, and interpretation. The involvement of noncoding RNAs in human diseases highlights their potential as biomarkers and therapeutic targets to facilitate the precision medicine. In this chapter, we give a brief overview of the bioinformatics tools to analyze different aspects of RNAs, in particular ncRNAs. We first describe the emerging bioinformatics methods for RNA identification, structure modeling, functional annotation, and network inference. This is followed by an introduction of potential usefulness of ncRNAs as diagnostic, prognostic biomarkers and therapeutic strategies.

  1. Precision alignment and mounting apparatus

    NASA Technical Reports Server (NTRS)

    Preston, Dennis R. (Inventor)

    1993-01-01

    An alignment and mounting apparatus for mounting two modules (10,12) includes a first portion having a cylindrical alignment pin (16) projecting normal to a module surface, a second portion having a three-stage alignment guide (18) including a shoehorn flange (34), a Y-slot (42) and a V-block (22) which sequentially guide the alignment pin (16) with successively finer precision and a third portion in the form of a spring-loaded captive fastener (20) for connecting the two modules after alignment is achieved.

  2. Axion Bounds from Precision Cosmology

    SciTech Connect

    Raffelt, G. G.; Hamann, J.; Hannestad, S.; Mirizzi, A.; Wong, Y. Y. Y.

    2010-08-30

    Depending on their mass, axions produced in the early universe can leave different imprints in cosmic structures. If axions have masses in the eV-range, they contribute a hot dark matter fraction, allowing one to constrain m{sub a} in analogy to neutrinos. In the more favored scenario where axions play the role of cold dark matter and if reheating after inflation does not restore the Peccei-Quinn symmetry, the axion field provides isocurvature fluctuations that are severely constrained by precision cosmology. There remains a small sliver in parameter space where isocurvature fluctuations could still show up in future probes.

  3. Precision ozone vapor pressure measurements

    NASA Technical Reports Server (NTRS)

    Hanson, D.; Mauersberger, K.

    1985-01-01

    The vapor pressure above liquid ozone has been measured with a high accuracy over a temperature range of 85 to 95 K. At the boiling point of liquid argon (87.3 K) an ozone vapor pressure of 0.0403 Torr was obtained with an accuracy of + or - 0.7 percent. A least square fit of the data provided the Clausius-Clapeyron equation for liquid ozone; a latent heat of 82.7 cal/g was calculated. High-precision vapor pressure data are expected to aid research in atmospheric ozone measurements and in many laboratory ozone studies such as measurements of cross sections and reaction rates.

  4. An Arbitrary Precision Computation Package

    SciTech Connect

    2003-06-14

    This package permits a scientist to perform computations using an arbitrarily high level of numeric precision (the equivalent of hundreds or even thousands of digits), by making only minor changes to conventional C++ or Fortran-90 soruce code. This software takes advantage of certain properties of IEEE floating-point arithmetic, together with advanced numeric algorithms, custom data types and operator overloading. Also included in this package is the "Experimental Mathematician's Toolkit", which incorporates many of these facilities into an easy-to-use interactive program.

  5. Magnetic fabrics in L-S tectonites: How many specimens?

    NASA Astrophysics Data System (ADS)

    Borradaile, Graham J.; Shortreed, Christopher

    2011-04-01

    Single large blocks (10-30 kg) of homogeneously strained, fine-grained slate or schist with homogeneous fabrics reveal subtle but sometimes significant variations in magnetic fabric from large numbers (up to 100) of closely spaced cylindrical cores. Traditional samples of three to six cores per block or per site may suffice for low precision, regional determinations of fabric orientations, if suitably fine-grained and homogeneous. However, for the most precise definition of anisotropy of magnetic susceptibility axes (AMS), small sample sizes (<15 cores) yield inconsistent orientations and shapes of the mean tensor. Coarse grain size would exacerbate these shortcomings since individual cores fail to sample the fabric representatively and inter-specimen variation may exceed inter-site variation in AMS. Fine-grained homogeneous rocks most successfully yield reproducible AMS orientations, and more especially AMS shapes. The optimum number of cores is best determined by experimentation since it depends on fabric heterogeneity, mineral proportions and grain-size variations at the inter-site and intra-site level.

  6. Wafer-scale micro-optics fabrication

    NASA Astrophysics Data System (ADS)

    Voelkel, Reinhard

    2012-07-01

    Micro-optics is an indispensable key enabling technology for many products and applications today. Probably the most prestigious examples are the diffractive light shaping elements used in high-end DUV lithography steppers. Highly-efficient refractive and diffractive micro-optical elements are used for precise beam and pupil shaping. Micro-optics had a major impact on the reduction of aberrations and diffraction effects in projection lithography, allowing a resolution enhancement from 250 nm to 45 nm within the past decade. Micro-optics also plays a decisive role in medical devices (endoscopes, ophthalmology), in all laser-based devices and fiber communication networks, bringing high-speed internet to our homes. Even our modern smart phones contain a variety of micro-optical elements. For example, LED flash light shaping elements, the secondary camera, ambient light and proximity sensors. Wherever light is involved, micro-optics offers the chance to further miniaturize a device, to improve its performance, or to reduce manufacturing and packaging costs. Wafer-scale micro-optics fabrication is based on technology established by the semiconductor industry. Thousands of components are fabricated in parallel on a wafer. This review paper recapitulates major steps and inventions in wafer-scale micro-optics technology. The state-of-the-art of fabrication, testing and packaging technology is summarized.

  7. Fabrication issues and technology development for HELEOS

    SciTech Connect

    Susoeff, A.R.; Hawke, R.S. ); Balk, J.K.; Hall, C.A.; McDonald, M.J. )

    1989-01-01

    Starfire is a joint railgun of Lawrence Livermore National Laboratory and Sandia National Laboratory-Albuquerque. The goal of Starfire is to develop a Hypervelocity Electromagnetic Launcher for Equation of State (HELEOS) experiments. A two-stage light-gas gun is used as a pre-injector. Each round-bore HELEOS railgun module is 12.7 mm in diameter and 2.4 m long. The muzzle end of the railgun is connected to a vacuum tank. Common materials and fabrication technology are used in the manufacture of all components, and modular design allows for extending the length of the railgun as progress dictates. The launcher uses a vee block geometry, which is designed to: (1) provide compressive preload, (2) operate with a 300-MPa (3-kbar) internal bore pressure, and (3) easily accommodate interchangeable materials in the bore support structure and rail. The authors have performed full-scale material testing of the railgun and have developed a precision round-bore fabrication process. Air-gage inspection is used to determine bore diameter and straightness. They have also developed a surface mapping system to document the surface topography of the bore before and after an experiment. This paper presents fabrication details, results of tests conducted, and areas for potential improvement.

  8. Miniature Scroll Pumps Fabricated by LIGA

    NASA Technical Reports Server (NTRS)

    Wiberg, Dean; Shcheglov, Kirill; White, Victor; Bae, Sam

    2009-01-01

    Miniature scroll pumps have been proposed as roughing pumps (low - vacuum pumps) for miniature scientific instruments (e.g., portable mass spectrometers and gas analyzers) that depend on vacuum. The larger scroll pumps used as roughing pumps in some older vacuum systems are fabricated by conventional machining. Typically, such an older scroll pump includes (1) an electric motor with an eccentric shaft to generate orbital motion of a scroll and (2) conventional bearings to restrict the orbital motion to a circle. The proposed miniature scroll pumps would differ from the prior, larger ones in both design and fabrication. A miniature scroll pump would include two scrolls: one mounted on a stationary baseplate and one on a flexure stage (see figure). An electromagnetic actuator in the form of two pairs of voice coils in a push-pull configuration would make the flexure stage move in the desired circular orbit. The capacitance between the scrolls would be monitored to provide position (gap) feedback to a control system that would adjust the drive signals applied to the voice coils to maintain the circular orbit as needed for precise sealing of the scrolls. To minimize power consumption and maximize precision of control, the flexure stage would be driven at the frequency of its mechanical resonance. The miniaturization of these pumps would entail both operational and manufacturing tolerances of <1 m. Such tight tolerances cannot be achieved easily by conventional machining of high-aspect-ratio structures like those of scroll-pump components. In addition, the vibrations of conventional motors and ball bearings exceed these tight tolerances by an order of magnitude. Therefore, the proposed pumps would be fabricated by the microfabrication method known by the German acronym LIGA ( lithographie, galvanoformung, abformung, which means lithography, electroforming, molding) because LIGA has been shown to be capable of providing the required tolerances at large aspect ratios.

  9. The Fabric of Reality

    NASA Astrophysics Data System (ADS)

    Whitaker, Andrew

    David Deutsch, The Fabric of Reality (London: Allen Lane, 1997), x+390 pp., ISBN 0-713-990619, hardback. David Deutsch's popular book, The Fabric of Reality, has already won acclaim as a sustained and comprehensible explanation of his own worldview, which encompasses his four main strands of quantum physics, epistemology, computation and evolution, as well as the many connections between them. Deutsch is a strong opponent of reductionism, and the latter three strands are 'high level' theories compared to quantum physics; but all four are to be regarded as fundamental because they are the theories that provide the deepest explanations. Deutsch considers that his worldview may be called the first genuine Theory of Everything; it would stand in strong contrast to the reductionist theories given that title at present. In fact he believes his approach may enable us to unify and explain not just science, but philosophy, logic, mathematics, ethics, politics and aesthetics.

  10. Fabrication of Nanochannels

    PubMed Central

    Zhang, Yuqi; Kong, Xiang-Yu; Gao, Loujun; Tian, Ye; Wen, Liping; Jiang, Lei

    2015-01-01

    Nature has inspired the fabrication of intelligent devices to meet the needs of the advanced community and better understand the imitation of biology. As a biomimetic nanodevice, nanochannels/nanopores aroused increasing interest because of their potential applications in nanofluidic fields. In this review, we have summarized some recent results mainly focused on the design and fabrication of one-dimensional nanochannels, which can be made of many materials, including polymers, inorganics, biotic materials, and composite materials. These nanochannels have some properties similar to biological channels, such as selectivity, voltage-dependent current fluctuations, ionic rectification current and ionic gating, etc. Therefore, they show great potential for the fields of biosensing, filtration, and energy conversions. These advances can not only help people to understand the living processes in nature, but also inspire scientists to develop novel nanodevices with better performance for mankind. PMID:28793564

  11. Directed light fabrication

    SciTech Connect

    Lewis, G.K.; Nemec, R.; Milewski, J.; Thoma, D.J.; Cremers, D.; Barbe, M.

    1994-09-01

    Directed Light Fabrication (DLF) is a rapid prototyping process being developed at Los Alamos National Laboratory to fabricate metal components. This is done by fusing gas delivered metal powder particles in the focal zone of a laser beam that is, programmed to move along or across the part cross section. Fully dense metal is built up a layer at a time to form the desired part represented by a 3 dimensional solid model from CAD software. Machine ``tool paths`` are created from the solid model that command the movement and processing parameters specific to the DLF process so that the part can be built one layer at a time. The result is a fully dense, near net shape metal part that solidifies under rapid solidification conditions.

  12. Ceramic fabrication R D

    SciTech Connect

    Not Available

    1990-01-01

    This project is separated into three tasks. The first task is a design and modeling effort to be carried out by MSE, Inc. The purpose of this task is to develop and analyze designs for various cohesive ceramic fabrication (CCF) components, including an MHD electrode for strategic defense initiative (SDI) applications and a high stress, low cost, reinforced ceramic component for armor applications. The MHD electrode design is substantially completed. A layered structure composed of molybdenum disilicide graded with quartz glass has been designed and analyzed using finite element methods. The design demonstrates the fabrication capabilities of the CCF process. The high stress, armor application component will be silicon carbide reinforced alumina in thick plates. 2 refs., 4 figs., 1 tab.

  13. Directed light fabrication

    NASA Astrophysics Data System (ADS)

    Lewis, G. K.; Nemec, R.; Milewski, J.; Thoma, D. J.; Cremers, D.; Barbe, M.

    1994-09-01

    Directed Light Fabrication (DLF) is a rapid prototyping process being developed at Los Alamos National Laboratory to fabricate metal components. This is done by fusing gas delivered metal powder particles in the focal zone of a laser beam that is programmed to move along or across the part cross section. Fully dense metal is built up a layer at a time to form the desired part represented by a 3 dimensional solid model from CAD software. Machine 'tool paths' are created from the solid model that command the movement and processing parameters specific to the DLF process so that the part can be built one layer at a time. The result is a fully dense, near net shape metal part that solidifies under rapid solidification conditions.

  14. Automated fabric inspection system

    NASA Astrophysics Data System (ADS)

    Jarvis, Christine W.

    1993-10-01

    The Automatic Fabric Inspection System developed by Systronics Inc. for Clemson Apparel Research uses vision technology to acquire images of the fabric two thousand times per second. Each image-video line consisting of 2048 picture elements is analyzed by a signal processing module and a decision on defect presence and location is made. A product norm signal is first established by having the system acquire an image of an unflawed stripe of the product. The output of each picture element (pixel) is digitized to a grey scale value in the 0-255 range. Threshold levels for defects with grey scale values higher and lower than product norm can then be established and set. The system will then compare all subsequent images against the set thresholds.

  15. Fabrication of diamond shells

    DOEpatents

    Hamza, Alex V.; Biener, Juergen; Wild, Christoph; Woerner, Eckhard

    2016-11-01

    A novel method for fabricating diamond shells is introduced. The fabrication of such shells is a multi-step process, which involves diamond chemical vapor deposition on predetermined mandrels followed by polishing, microfabrication of holes, and removal of the mandrel by an etch process. The resultant shells of the present invention can be configured with a surface roughness at the nanometer level (e.g., on the order of down to about 10 nm RMS) on a mm length scale, and exhibit excellent hardness/strength, and good transparency in the both the infra-red and visible. Specifically, a novel process is disclosed herein, which allows coating of spherical substrates with optical-quality diamond films or nanocrystalline diamond films.

  16. Precision Mass Measurements at CARIBU

    NASA Astrophysics Data System (ADS)

    Lascar, D.; van Schelt, J.; Savard, G.; Caldwell, S.; Chaudhuri, A.; Clark, J. A.; Levand, A. F.; Li, G.; Sternberg, M.; Sun, T.; Zabransky, B. J.; Segel, R.; Sharma, K.

    2010-02-01

    Neutron separation energies (Sn) are essential inputs to models of explosive r-process nucleosynthesis. However, for nuclei farther from stability, the precision of Sn decreases as production decreases and observation of those nuclei become more difficult. Many of the most critical inputs to the models are based on extrapolations from measurements of masses closer to stability than the predicted r-process path. Measuring masses that approach and lie on the predicted r-process path will further constrain the systematic uncertainties in these extrapolated values. The Canadian Penning Trap Mass Spectrometer (CPT) at Argonne National Laboratory (ANL) has measured the masses of more than 160 nuclei to high precision. A recent move to the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) at ANL has given the CPT unique access to weakly produced nuclei that cannot be easily reached via proton induced fission of ^238U. CARIBU will eventually use a 1 Ci source of ^252Cf to produce these nuclei. Installation of the CPT at CARIBU as well as the first CPT mass measurements of neutron rich nuclei at CARIBU will be discussed. )

  17. Automatic precision measurement of spectrograms.

    PubMed

    Palmer, B A; Sansonetti, C J; Andrew, K L

    1978-08-01

    A fully automatic comparator has been designed and implemented to determine precision wavelengths from high-resolution spectrograms. The accuracy attained is superior to that of an experienced operator using a semiautomatic comparator with a photoelectric setting device. The system consists of a comparator, slightly modified for simultaneous data acquisition from two parallel scans of the spectrogram, interfaced to a minicomputer. The software which controls the system embodies three innovations of special interest. (1) Data acquired from two parallel scans are compared and used to separate unknown from standard lines, to eliminate spurious lines, to identify blends of unknown with standard lines, to improve the accuracy of the measured positions, and to flag lines which require special examination. (2) Two classes of lines are automatically recognized and appropriate line finding methods are applied to each. This provides precision measurement for both simple and complex line profiles. (3) Wavelength determination using a least-squares fitted grating equation is supported in addition to polynomial interpolation. This is most useful in spectral regions with sparsely distributed standards. The principles and implementation of these techniques are fully described.

  18. Precision metrology using weak measurements.

    PubMed

    Zhang, Lijian; Datta, Animesh; Walmsley, Ian A

    2015-05-29

    Weak values and measurements have been proposed as a means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur with highly suppressed probabilities. This raises three vital questions in weak-measurement-based metrology. Namely, (Q1) Does postselection enhance the measurement precision? (Q2) Does weak measurement offer better precision than strong measurement? (Q3) Is it possible to beat the standard quantum limit or to achieve the Heisenberg limit with weak measurement using only classical resources? We analyze these questions for two prototypical, and generic, measurement protocols and show that while the answers to the first two questions are negative for both protocols, the answer to the last is affirmative for measurements with phase-space interactions, and negative for configuration space interactions. Our results, particularly the ability of weak measurements to perform at par with strong measurements in some cases, are instructive for the design of weak-measurement-based protocols for quantum metrology.

  19. Precision Environmental Radiation Monitoring System

    SciTech Connect

    Vladimir Popov, Pavel Degtiarenko

    2010-07-01

    A new precision low-level environmental radiation monitoring system has been developed and tested at Jefferson Lab. This system provides environmental radiation measurements with accuracy and stability of the order of 1 nGy/h in an hour, roughly corresponding to approximately 1% of the natural cosmic background at the sea level. Advanced electronic front-end has been designed and produced for use with the industry-standard High Pressure Ionization Chamber detector hardware. A new highly sensitive readout electronic circuit was designed to measure charge from the virtually suspended ionization chamber ion collecting electrode. New signal processing technique and dedicated data acquisition were tested together with the new readout. The designed system enabled data collection in a remote Linux-operated computer workstation, which was connected to the detectors using a standard telephone cable line. The data acquisition system algorithm is built around the continuously running 24-bit resolution 192 kHz data sampling analog to digital convertor. The major features of the design include: extremely low leakage current in the input circuit, true charge integrating mode operation, and relatively fast response to the intermediate radiation change. These features allow operating of the device as an environmental radiation monitor, at the perimeters of the radiation-generating installations in densely populated areas, like in other monitoring and security applications requiring high precision and long-term stability. Initial system evaluation results are presented.

  20. Helium 3 neutron precision polarimetry

    NASA Astrophysics Data System (ADS)

    Menard, Christopher

    2009-10-01

    Measuring neutron polarization to a high degree of precision is critical for the next generation of neutron decay correlation experiments. Polarized neutrons are also used in experiments to probe the hadronic weak interaction which contributes a small portion (˜10-7) of the force between nucleons. Using a beam of cold neutrons at Los Alamos Neutron Science Center (LANSCE), we polarized neutrons and measured their absolute polarization to ˜0.1%. Neutrons were polarized by passing them through a ^3He spin filter, relying on the maximally spin dependent 3He neutron absorption cross section. The neutron polarization can be determined by measuring the wavelength-dependent neutron transmission through the ^3He cell. An independent measurement of the neutron polarization was also obtained by passing the polarized beam through an RF spin flipper and a second polarized ^3He cell, used as an analyzer. To measure the efficiency of the spin flipper, the same measurements were made after reversing the ^3He polarization in the polarizer by using NMR techniques (adiabatic fast passage). We will show the consistency of these two measurements and the resulting precision of neutron polarimetry using these techniques.

  1. Precision Measurements in 37K

    NASA Astrophysics Data System (ADS)

    Anholm, Melissa; Ashery, Daniel; Behling, Spencer; Fenker, Benjamin; Melconian, Dan; Mehlman, Michael; Behr, John; Gorelov, Alexandre; Olchanski, Konstantin; Preston, Claire; Warner, Claire; Gwinner, Gerald

    2015-10-01

    We have performed precision measurements of the kinematics of the daughter particles in the decay of 37K. This isotope decays by β+ emission in a mixed Fermi/Gamow-Teller transition to its isobaric analog, 37Ar. Because the higher-order standard model corrections to this decay process are well understood, it is an ideal candidate for for improving constraints on interactions beyond the standard model. Our setup utilizes a magneto-optical trap to confine and cool samples of 37K, which are then spin-polarized by optical pumping. This allows us to perform measurements on both polarized and unpolarized nuclei, which is valuable for a complete understanding of systematic effects. Precision measurements of this decay are expected to be sensitive to the presence of right-handed vector currents, as well as a linear combination of scalar and tensor currents. Progress towards a final result is presented here. Support provided by: NSERC, NRC through TRIUMF, DOE ER40773, Early Career ER41747, Israel Science Foundation.

  2. Antihydrogen production and precision experiments

    SciTech Connect

    Nieto, M.M.; Goldman, T.; Holzscheiter, M.H.

    1996-12-31

    The study of CPT invariance with the highest achievable precision in all particle sectors is of fundamental importance for physics. Equally important is the question of the gravitational acceleration of antimatter. In recent years, impressive progress has been achieved in capturing antiprotons in specially designed Penning traps, in cooling them to energies of a few milli-electron volts, and in storing them for hours in a small volume of space. Positrons have been accumulated in large numbers in similar traps, and low energy positron or positronium beams have been generated. Finally, steady progress has been made in trapping and cooling neutral atoms. Thus the ingredients to form antihydrogen at rest are at hand. Once antihydrogen atoms have been captured at low energy, spectroscopic methods can be applied to interrogate their atomic structure with extremely high precision and compare it to its normal matter counterpart, the hydrogen atom. Especially the 1S-2S transition, with a lifetime of the excited state of 122 msec and thereby a natural linewidth of 5 parts in 10{sup 16}, offers in principle the possibility to directly compare matter and antimatter properties at a level of 1 part in 10{sup 16}.

  3. Precision experiments in electroweak interactions

    SciTech Connect

    Swartz, M.L.

    1990-03-01

    The electroweak theory of Glashow, Weinberg, and Salam (GWS) has become one of the twin pillars upon which our understanding of all particle physics phenomena rests. It is a brilliant achievement that qualitatively and quantitatively describes all of the vast quantity of experimental data that have been accumulated over some forty years. Note that the word quantitatively must be qualified. The low energy limiting cases of the GWS theory, Quantum Electrodynamics and the V-A Theory of Weak Interactions, have withstood rigorous testing. The high energy synthesis of these ideas, the GWS theory, has not yet been subjected to comparably precise scrutiny. The recent operation of a new generation of proton-antiproton (p{bar p}) and electron-positron (e{sup +}e{sup {minus}}) colliders has made it possible to produce and study large samples of the electroweak gauge bosons W{sup {plus minus}} and Z{sup 0}. We expect that these facilities will enable very precise tests of the GWS theory to be performed in the near future. In keeping with the theme of this Institute, Physics at the 100 GeV Mass Scale, these lectures will explore the current status and the near-future prospects of these experiments.

  4. Precision medicine in pediatric rheumatology.

    PubMed

    Yeo, Joo Guan; Ng, Chin Teck; Albani, Salvatore

    2017-09-01

    Precision medicine is the tailoring of medical care to subcategories of disease. In pediatric rheumatology, these subcategories must first be defined by their specific molecular immunological profiles, and then the effects of growth and puberty, developmental immunological changes, and differences in treatment options and adherence considered when designing therapeutic strategies. In the present review, we summarize the unmet needs in pediatric rheumatology before such precision medical care can be effectively delivered to affected patients. The current clinical classification of pediatric rheumatic diseases does not provide all the information necessary for prognostication and accurate therapeutic selection. Many studies have highlighted the molecular differences between disease subcategories and the dissimilarities in the molecular manifestations of the same disease between patients. Harnessing such discoveries by collaborating with various research networks and laboratories is required to interrogate the multifactorial nature of rheumatic diseases in a holistic manner. Integration of big data sets generated from well defined pediatric cohorts with rheumatic diseases using different high-dimensional technological platforms will help to elucidate the underlying disease mechanisms. Distilling these data will be necessary for accurate disease stratification and will have a positive impact on prognosis and treatment choice.

  5. Superconducting Wire Fabrication

    DTIC Science & Technology

    1990-05-01

    dichrom ate ................................................. 12 12. Copper container, prereacted 1-2-3 powder core, 1 hour at 910 0 C, as p o lish ed...hour at 910 0 C, etched with ammonium hydrogen peroxide solution ................................ 15 18. Silver container, prereacted 1-2-3 powder core...this effort. First, it was necessary to gain experience in the fabrication and characterization of bulk superconductors. Also, experiments were done

  6. Space Fabrication Demonstration System

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The completion of assembly of the beam builder and its first automatic production of truss is discussed. A four bay, hand assembled, roll formed members truss was built and tested to ultimate load. Detail design of the fabrication facility (beam builder) was completed and designs for subsystem debugging are discussed. Many one bay truss specimens were produced to demonstrate subsystem operation and to detect problem areas.

  7. Space Fabrication Demonstration System

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Progress in the mechanical/structural assembly of the beam builder is reported. The following structures were investigated: cross brace magazine/dispenser subsystem; and rolling mill supply reel, guide, and drive. The fabrication facility design and a detail design of all major subsystem components are discussed. The number of spot welds per structural joint were reduced which enables the doubling of length of truss which can be produced within known electrode life limits.

  8. Space Fabrication Demonstration System

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Progress on fabrication facility (beam builder) support structure control, clamp/weld block, and welding and truss cut off is discussed. The brace attachment design was changed and the design of the weld mechanism was modified which achieved the following system benefits: (1) simplified weld electrode life; (2) reduced weld power requirements; and (3) simplified brace attachment mechanisms. Static and fatigue characteristics of spot welded 2024T3 aluminum joints are evaluated.

  9. Space Fabrication Demonstration System

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Progress in the development of a beam builder to be deployed by space shuttle for assembly of large structures in space is reported. The thermal coating for the structural truss was selected and the detail truss design and analysis completed. Data acquired during verification of the design of the basic 'building block' truss are included as well as design layouts for various fabrication facility subsystems.

  10. High precision optical surface metrology using deflectometry

    NASA Astrophysics Data System (ADS)

    Huang, Run

    Software Configurable Optical Test System (SCOTS) developed at University of Arizona is a highly efficient optical metrology technique based on the principle of deflectometry, which can achieve comparable accuracy with interferometry but with low-cost hardware. In a SCOTS test, an LCD display is used to generate structured light pattern to illuminate the test optics and the reflected light is captured by a digital camera. The surface slope of test optics is determined by triangulation of the display pixels, test optics, and the camera. The surface shape is obtained by the integration of the slopes. Comparing to interferometry, which has long served as an accurate non-contact optical metrology technology, SCOTS overcomes the limitation of dynamic range and sensitivity to environment. It is able to achieve high dynamic range slope measurement without requiring null optics. In this dissertation, the sensitivity and performance of the test system have been analyzed comprehensively. Sophisticated calibrations of system components have been investigated and implemented in different metrology projects to push this technology to a higher accuracy including low-order terms. A compact on-axis SCOTS system lowered the testing geometry sensitivity in the metrology of 1-meter highly aspheric secondary mirror of Large Binocular Telescope. Sub-nm accuracy was achieved in testing a high precision elliptical X-ray mirror by using reference calibration. A well-calibrated SCOTS was successfully constructed and is, at the time of writing this dissertation, being used to provide surface metrology feedback for the fabrication of the primary mirror of Daniel K. Inouye Solar Telescope which is a 4-meter off-axis parabola with more than 8 mm aspherical departure.

  11. Precision linear shaped charge analyses for severance of metals

    SciTech Connect

    Vigil, M.G.

    1996-08-01

    The Precision Linear Shaped Charge (PLSC) design concept involves the independent fabrication and assembly of the liner (wedge of PLSC), the tamper/confinement, and explosive. The liner is the most important part of a linear shaped charge (LSC) and should be fabricated by a more quality controlled, precise process than the tamper material. Also, this concept allows the liner material to be different from the tamper material. The explosive can be loaded between the liner and tamper as the last step in the assembly process rather than the first step as in conventional LSC designs. PLSC designs have been shown to produce increased jet penetrations in given targets, more reproducible jet penetration, and more efficient explosive cross-section geometries using a minimum amount of explosive. The Linear Explosive Shaped Charge Analysis (LESCA) code developed at Sandia National Laboratories has been used to assist in the design of PLSCs. LESCA predictions for PLSC jet tip velocities, jet-target impact angles, and jet penetration in aluminum and steel targets are compared to measured data. The advantages of PLSC over conventional LSC are presented. As an example problem, the LESCA code was used to analytically develop a conceptual design for a PLSC component to sever a three-inch thick 1018 steel plate at a water depth of 500 feet (15 atmospheres).

  12. Atomically Traceable Nanostructure Fabrication.

    PubMed

    Ballard, Josh B; Dick, Don D; McDonnell, Stephen J; Bischof, Maia; Fu, Joseph; Owen, James H G; Owen, William R; Alexander, Justin D; Jaeger, David L; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J; Wallace, Robert M; Reidy, Richard; Silver, Richard M; Randall, John N; Von Ehr, James

    2015-07-17

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

  13. Atomically Traceable Nanostructure Fabrication

    PubMed Central

    Ballard, Josh B.; Dick, Don D.; McDonnell, Stephen J.; Bischof, Maia; Fu, Joseph; Owen, James H. G.; Owen, William R.; Alexander, Justin D.; Jaeger, David L.; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J.; Wallace, Robert M.; Reidy, Richard; Silver, Richard M.; Randall, John N.; Von Ehr, James

    2015-01-01

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure. PMID:26274555

  14. The Testing of Airplane Fabrics

    NASA Technical Reports Server (NTRS)

    Schraivogel, Karl

    1932-01-01

    This report considers the determining factors in the choice of airplane fabrics, describes the customary methods of testing and reports some of the experimental results. To sum up briefly the results obtained with the different fabrics, it may be said that increasing the strength of covering fabrics by using coarser yarns ordinarily offers no difficulty, because the weight increment from doping is relatively smaller.

  15. Handbook for estimating fabrication costs

    NASA Technical Reports Server (NTRS)

    Freeman, L. M.

    1978-01-01

    Guide helps design engineers determine total cost of fabricating electronic equipment. It contains tables of "factors" for determining costs associated with fabrication. "Standards" section includes estimations of time required for procedures ranging from machining, to wiring, to printed-circuit board fabrication.

  16. Direct-write fabrication of integrated, multilayer ceramic components

    SciTech Connect

    Dimos, D.; Yang, P.

    1998-03-01

    The need for advanced (electronic) ceramic components with smaller size, greater functionality, and enhanced reliability requires the ability to integrate electronic ceramics in complex 3-D architectures. However, traditional tape casting and screen printing approaches are poorly suited to the requirements of rapid prototyping and small lot manufacturing. To address this need, the authors are developing a direct write approach for fabricating highly integrated, multilayer components using a micropen to deposit slurries in precise patterns. This approach provides the ability to fabricate multifunctional, multimaterial integrated ceramic components (MMICCs) in an agile and rapid way, and has been used to make integrated passive devices such RC filters, inductors, and voltage transformers.

  17. Fabrication of polydimethylsiloxane (PDMS) - based multielectrode array for neural interface.

    PubMed

    Kim, Jun-Min; Oh, Da-Rong; Sanchez, Joaquin; Kim, Shang-Hyub; Seo, Jong-Mo

    2013-01-01

    Flexible multielectrode arrays (MEAs) are being developed with various materials, and polyimide has been widely used due to the conveniece of process. Polyimide is developed in the form of photoresist. And this enable precise and reproducible fabrication. PDMS is another good candidate for MEA base material, but it has poor surface energy and etching property. In this paper, we proposed a better fabrication process that could modify PDMS surface for a long time and open the site of electrode and pad efficiently without PDMS etching.

  18. Characterization of the lattice defects in Ge-ion implanted ZnO bulk single crystals by Rutherford Backscattering: Origins of low resistivity

    NASA Astrophysics Data System (ADS)

    Kamioka, K.; Oga, T.; Izawa, Y.; Kuriyama, K.; Kushida, K.

    2013-07-01

    A Ge ion implantation using a multiple-step energy into ZnO bulk single crystals is performed (net concentration: 2.6 × 1020 cm-3). The origins of low resistivity of the Ge implanted ZnO samples are studied by Rutherford backscattering spectroscopy (RBS), photoluminescence (PL). The resistivity measured by Van der Pauw method decreases from ˜103 Ωcm for the un-implanted samples to 1.45 × 10-2 Ωcm for the as-implanted samples, originating from the lattice displacement of Zn (Zni) (˜30 meV [Look et al., Phys. Rev. Lett. 82, 2552 (1999)]), the existence of which is revealed by the RBS measurements. In contrast, the 1000 °C annealed samples show the higher resistivity of 6.26 × 10-1 Ωcm, indicating that the Zni related defects decrease but still remain despite the annealing. A new PL emission appears at around 372 nm (3.33 eV) in the annealed samples, suggesting a Ge donor with an activation energy of 100 meV. This value corresponds to the activation energy (102 meV) of a Ge donor estimated from the temperature dependence of carrier concentration. These results suggest that the resistivity in the 1000 °C annealed samples results from both the Zni related defects and the electrically activated Ge donor.

  19. Spatial clustering of defect luminescence centers in Si-doped low resistivity Al0.82Ga0.18N

    NASA Astrophysics Data System (ADS)

    Kusch, Gunnar; Nouf-Allehiani, M.; Mehnke, Frank; Kuhn, Christian; Edwards, Paul R.; Wernicke, Tim; Knauer, Arne; Kueller, Viola; Naresh-Kumar, G.; Weyers, Markus; Kneissl, Michael; Trager-Cowan, Carol; Martin, Robert W.

    2015-08-01

    A series of Si-doped AlN-rich AlGaN layers with low resistivities was characterized by a combination of nanoscale imaging techniques. Utilizing the capability of scanning electron microscopy to reliably investigate the same sample area with different techniques, it was possible to determine the effect of doping concentration, defect distribution, and morphology on the luminescence properties of these layers. Cathodoluminescence shows that the dominant defect luminescence depends on the Si-doping concentration. For lower doped samples, the most intense peak was centered between 3.36 eV and 3.39 eV, while an additional, stronger peak appears at 3 eV for the highest doped sample. These peaks were attributed to the (VIII-ON)2- complex and the VIII 3 - vacancy, respectively. Multimode imaging using cathodoluminescence, secondary electrons, electron channeling contrast, and atomic force microscopy demonstrates that the luminescence intensity of these peaks is not homogeneously distributed but shows a strong dependence on the topography and on the distribution of screw dislocations.

  20. Effect of vertical heterogeneities in a petrophysical evaluation of low resistivity pay zones, B sands, upper Eocene, Block III, Lake Maracaibo

    SciTech Connect

    Coll, C.; Cortiula, B.; Gonzalez, G.; Meza, E.; Rondon, L.

    1996-08-01

    Thin-bed reservoirs can exist as intercalations of thin porous beds and shales. For a proper petrophysical evaluation and geological characterization of this type of reservoir it is necessary to implement an integrated analysis, which includes knowledge of the depositional environment to avoid missing oil zones by applying standard petrophysical evaluations. The normal resistivity logs used on this area do not have enough vertical resolution for detecting thin low resistivity pay zones. Consequently, the common water saturation models indicate high water saturation when they are evaluated. The Middle Eocene Upper B sands are part of the Misoa Formation in Block III of Lake Maracaibo. They have been exploited since 1965 when the first production test was made. The cumulative oil production to date stands at 11.49 MMSTB. In order to supplement the existing geological information in this area, a continuous core was taken which showed the high degree of shales and thin sands intercalations in the pay zone. A careful core-log calibration was made and a new set of petrophysical parameters were established for this reservoir based on the core measurements. This allowed the establishment of a new petrophysical evaluation procedure that helps the calculation of permeability, hydrocarbon volume in place and productivity of this reservoir.