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A NEW STABILIZATION OF ADAPTIVE STEP TRAPEZOID RULE BASED ON FINITE DIFFERENCE INTERRUPTS
No full textThe adaptive step trapezoid rule (TR) is a generally effective numerical integrator, but it is prone to ringing instability and solution stall. We introduce a new stabilization algorithm based on finite difference interrupts (FDI) that reduces ringing and prevents stall. Unlike previously reported stabilization schemes, our algorithm achieves stability and second order accuracy without incurring significant computational cost or spurious diffusion. TR with FDI is at least as stable and accurate as existing methods when solving the prototypical scalar problem. We demonstrate that it has better stability, accuracy, and cost when solving the tightly coupled system describing free surface flows of viscoelastic liquids. Though we demonstrate TR with FDI in the context of a finite element method-of-lines, it is applicable to any TR-based algorithm
The National Nanotechnology Initiative: Supplement to the President's 2016 Budget
No full textThis document is a supplement to the President’s 2016 Budget
request submitted to Congress on February 2, 2015, and
serves as the Annual Report for the National Nanotechnology Initiative called for under the provisions of the 21st Century Nanotechnology Research and Development Act of 2003 (Public Law 108 - 153, 15 U.S.C. §7501). The report also addresses the requirement for Department of Defense reporting on its nanotechnology investments, per 10 U.S.C. §2358. Chapter 1 provides an overview of the NNI, including a discussion of external reviews. Chapter 2 reports actual investments for 2014, estimated investments for 2015, and requested investments for 2016 by NNI Program Component Area (PCA), including investments under the Small Business Innovation Research (SBIR) and Small Business Technology Transfer Research(STTR) programs. Chapter 3 outlines changes in the balance of investments by PCA made by Federal agencies participating in the NNI. Chapter 4 describes activities that have been undertaken and progress that has been made toward achieving the four goals set out in the NNI Strategic Plan of 2014, including activities in support of the NNI Nanotechnology Signature Initiatives. Appendices include a list of abbreviations and acronyms and a contact list of staff members at NNI participating agencies and at the National Nanotechnology Coordination Office (NNCO). Additional information regarding the NNI is
available on the NNI website at www.nano.gov
Low-Temperature Fabrication of Mesoporous Titanium Dioxide Thin Films with Tunable Refractive Indices for One-Dimensional Photonic Crystals and Sensors on Rigid and Flexible Substrates
No full textHighly transparent mesoporous titanium dioxide (TiO2; anatase), thin films were prepared at room temperature via ultraviolet (UV) irradiation Of hybrid polymer-TiO2 nanoparticle thin films: This approach utilized a UV-curable polymer in conjunction with the photocatalytic activity of TiO2 to form and degrade the organic component of the composite films in one step, producing films with well-controlled porosity and refractive index. By adjustment of the loading of TiO2 nanoparticles in the host polymer, the refractive index was tuned between 1.53 and 1.73. Facile control of these properties and mild processing conditions was leveraged to fabricate robust one-dimensional photonic crystals (Bragg mirrors) consisting entirely of TiO2 on silicon and flexible poly(ethylene terephthalate) substrates. The mesoporous Bragg mirrors were shown to be effective chemical vapor sensors with strong optical responses
Wave Interference Functions for Neuromorphic Computing
No full textNeuromorphic computing mimicking the functionalities of mammalian brain holds the promise for cognitive capabilities enabling new intelligent applications. However, research efforts so far mainly focused on using analog and digital CMOS technologies to emulate neural activities, and are yet to achieve expected benefits. They suffer from limited scalability, density overhead, interconnection bottleneck and power consumption related constraints. In this paper, we present a transformative approach for neuromorphic computing with Wave Interference Functions (WIF). This is a framework using emerging nonequilibrium wave phenomenon such as spin waves. WIF leverages inherent wave attributes for multidimensional, multivalued data representation and communication, resulting in reduced connectivity requirements and efficient neural function implementations. It also yields a compact implementation of an artificial neuron. Moreover, since WIF computation and communication are in the spin domain, extremely low-power operation is possible. Our evaluations indicate upto 57xhigher density, 775xlower power and 2xbetter performance when compared to an equivalent 8-bit 45-nm CMOS neuron. Our scalability study using arithmetic circuits for higher bit-width neuron implementations indicate upto 63x density, 884x power and 3x performance benefits in comparison to a 32-bit CMOS equivalent design at 45 nm
Inkjet-Printed Gold Nanoparticle Surfaces for the Detection of Low Molecular Weight Biomolecules by Laser Desorption/Ionization Mass Spectrometry
No full textEffective detection of low molecular weight compounds in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is often hindered by matrix interferences in the low m/z region of the mass spectrum. Here, we show that monolayer-protected gold nanoparticles (AuNPs) can serve as alternate matrices for the very sensitive detection of low molecular weight compounds such as amino acids. Amino acids can be detected at low fmol levels with minimal interferences by properly choosing the AuNP deposition method, density, size, and monolayer surface chemistry. By inkjet-printing AuNPs at various densities, we find that AuNP clusters are essential for obtaining the greatest sensitivity
A facile approach to hydrophilic, reverse zwitterionic, choline phosphate polymers
No full text2-{2-(Methacryloyloxy) ethyldimethylammonium}ethyl n-butyl phosphate (MBP) was synthesized and polymerized by controlled free radical methods to afford a new set of ``reverse zwitterionic'' choline phosphate (CP) substituted polymers. The synthesis overcomes prior limitations associated with related CP-methacrylates, affording facile access to MBP homopolymers and MBP-containing diblock copolymers. Dynamic light scattering revealed the size of polyMBP in water, while cell culture assays showed polyMBP to have excellent biocompatibility and non-immunogenicity. The facile synthesis of MBP monomer, and the corresponding polymers, opens a new platform towards a diverse set of functional, hydrophilic biocompatible polymers
Nanowire Volatile RAM as an Alternative to SRAM
No full textMaintaining benefits of CMOS technology scaling is becoming challenging, primarily due to increased manufacturing complexities and unwanted passive power dissipations. This is particularly challenging in SRAM, where manufacturing precision and leakage power control are critical issues. To alleviate these challenges, we proposed a novel volatile memory alternative to SRAM called nanowire volatile RAM (NWRAM). Due to NWRAM's regular grid-based layout and innovative circuit style, manufacturing complexities are reduced and, at the same time, considerable benefits are attained in terms of performance and leakage power reduction. In this article we elaborate NWRAM's circuit aspects and manufacturability, and quantify benefits at 16nm technology node through simulation against state-of-the-art 6T-SRAM and gridded 8T-SRAM designs. Our results show that when lower bounds in design rules are considered, 10T-NWRAM's read and write time are 1.38x and 2x faster, and the leakage power is 14x better in comparison to high-performance 6T-SRAM. Similarly the 10T-NWRAM achieves 1.3x and 1.9x read and write performance, and 35x leakage power improvements compared to high-performance 8T-SRAM. 10T-NWRAM's density is comparable to 6T-SRAM and 8T-SRAM for lower bounds, but exhibits higher active power in similar comparisons. This article details all benchmarking results and provides thorough analysis of NWRAM's evaluations
Concentric circular trajectory sampling for super-resolution and image mosaicing
No full textUbiquitous applications in diverse fields motivate large-area sampling, super-resolution (SR) and image mosaicing. However, conventional translational sampling has drawbacks including laterally constrained variations between samples. Meanwhile, existing rotational sampling methods do not consider the uniformity of sampling points in Cartesian coordinates, resulting in additional distortion errors in sampled images. We design a novel optimized concentric circular trajectory sampling (OCCTS) method to acquire image information uniformly at fast sampling speeds. The sampling method allows multiple low-resolution images for conventional SR algorithms to be acquired by adding small variations in the angular dimension. Experimental results demonstrate that OCCTS can beat comparable CCTS methods that lack optimized sampling densities by reducing sampling time by more than 11.5% while maintaining 50% distortion error reduction. The SR quality of OCCTS has at least 5.2% fewer distortion errors than the comparable CCTS methods. This paper is the first, to the best of our knowledge, to present an OCCTS method for SR and image mosaicing. (C) 2015 Optical Society of Americ
Capillary-bridge-derived particles with negative Gaussian curvature
No full textWe report the preparation of millimeter-scale particles by thermal polymerization of liquid monomer capillary bridges to form catenoid-shaped particles that exhibit negative Gaussian curvature. The shape of the capillary bridges and resulting particles can be finely tuned using several addressable parameters: (i) the shape, size, and orientation of lithographic pinning features on the spanned surfaces; (ii) the distance between opposing support surfaces; and (iii) the lateral displacement (shear) of opposing features. The catenoid-shaped particles exhibit controllable optical properties as a result of their concave menisci, the shape of which can be easily manipulated. The particles self assemble in the presence of a condensing liquid (water) to form reversible neck-to-neck pairs and less reversible end-to-end aggregates. We argue that this approach could be scaled down to micrometer dimensions by fabricating an array of micrometer-scale particles. We also argue, with a discussion of dynamic wetting, that these particles will exhibit interesting anisotropic adhesive properties
Highly organized nanofiber formation from zero valent iron nanoparticles after cadmium water remediation
No full text' Many studies have used nanoscale zero valent iron (nZVI) nanoparticles to remove redox-sensitive metals (e. g., As, Cr, U, Se, Ni, Cu) from aqueous systems by absorption or reduction processes. However, very few investigations present a detailed study of the product formed after the remediation process. In order to quantify the efficiency of nZVI particles as a possible cadmium remediation agent, we prepared nZVI by sodium borohydride reduction of an iron complex, FeCl3 center dot 6H(2)O, at room temperature and ambient pressure. Fe-0 and nanocrystalline structures of iron oxides and oxyhydroxides were obtained with this method. We exposed the nZVI to 6 ppm of Cd2+ and characterized the products with X-ray diffraction, X-ray absorption and X-ray photoelectron spectroscopy. Inductively coupled plasma analysis showed that the nZVI remediation efficiency of cadmium ions was between 80% and 90% in aqueous media. All of the physical characterization results confirmed the presence of Fe-0, a-Fe2O3 and FeOOH. High resolution transmission electron microscopy images showed nanofiber formation of a mixture of Fe-0, oxyhydroxides and oxides iron formed after interacting with cadmium ions, possibly forming CdFe2O4. These results suggest that the FeOOH shell and other iron oxides in nZVI could enhance Cd2+ removal. This removal is observed to cause a change of the initial structure of nZVI to nanofibers due to possible formation of CdFe2O4 as a waste product