Oscillation criteria for first-order impulsive differential equations with positive and negative coefficients

AbstractSome sufficient conditions are obtained for oscillation of all solutions of the first-order impulsive differential equation with positive and negative coefficients[x(t)-R(t)x(t-r)]′+P(t)x(t-τ)-Q(t)x(t-σ)=0,τ⩾σ>0,t⩾t0,x(tk+)=Ik(x(tk)),k=1,2,….Our results improve the known results in the literature

Method of Forming Composite Materials including Conjugated Materials attached to Carbon Nanotubes or Graphenes (CIP)

A method of forming composite materials includes dispersing a conjugated material, a solvent for the conjugated material, and a plurality of carbon nanotubes (CNTs) or graphene including structures having an outer surface to form a dispersion. The solvent is evaporated from the dispersion to yield a CNT or graphene composite including a plurality of crystalline supramolecular structures having the conjugated material non-covalently secured to the outer surface of the CNT or the graphene including structure. The supramolecular structures have an average length which extends outward in a length direction from the outer surface of the CNT or graphene including structure, where the average length is greater than an average width of the supramolecular structures

Supramolecular Structures Comprising At Least Partially Conjugated Polymers Attached to Carbon Nanotubes and Graphenes

A composition of matter includes at least one carbon nanotube (CNT) or grapheme type structure having an outer surface and a plurality of crystalline polymer supramolecular structures that includes a conjugated polymer that are non-covalently secured to the outer surface of the CNTs or the grapheme type structure. The conjugated polymer can be a conjugated homopolymer or a block copolymer including at least one conjugated block. The supramolecular structures extend outward from the outer surface of the CNTs or grapheme type structures

Dispersions of Carbon Nanotubes in Copolymer Solutions and Functional Composite Materials and Coatings Therefrom

A dispersion includes non-chemically modified carbon nanotubes, a soluble block coploymer providing at least one block of a conjugated polymer, and at least one solvent. at 25 degrees C, exclusive of any mechanical force and after one hour, at least 90% of the carbon nanotubes exist in the dispersion as isolated nanotubes. The compenents of the dispersin can be combined with a polymer miscible with the block copolymer to form a carbon nanotube polymer composite upon removal of the solvent. The dispersion can be cast on a substrate and then dried to form a coating, including forming a superhydrophobic coating on the substrate. The non-conjugated polymer of the block copolymer or another miscible conjugated polymer including a copolymer can include functionalities that non-covalently attach to the carbon nanotube surface, such as for enhanced solubility or enhanced biocompatibility

LASER IRRADIATION OF METAL NANOPARTICLE/POLYMER COMPOSITE MATERIALS FOR CHEMICAL AND PHYSICAL TRANSFORMATIONS

A metal nanoparticle supported on or dispersed in a polymer is irradiated with photons from a laser source to address the nanoparticles. The polymer is transmissive to the photons and addressed nanoparticles transform the energy of the photon to heat which is transferred to a material in the vicinity of the nanoparticle. The locally heated material undergoes a physical or chemical transformation upon heating. The transformed material can be a material in the proximity of the metal nanoparticle supported polymer or metal nanoparticle/polymer composite. In this manner thermally induced physical or chemical transformations can be carried out in very small volumes of material without significant heating to the bulk of the materia

Anomaly and geochemistry of rare earth elements and yttrium in the late Permian coal from the Moxinpo mine, Chongqing, southwestern China

Abstract The rare earth elements and yttrium (REY) of the K2 coal from the Moxinpo mine, Chongqing, were determined using inductively coupled plasma mass spectrometry (ICP-MS). The results show that REY are enriched in the K2 coal, with the average content up to 462 μg/g, much higher than average values of most coals in the world. The REY distribution patterns indicate that the light REY is enriched and show a well-pronounced Eu minimum. The fractionation of individual light-REY is higher than that of the heavy-REY. The REY distribution through the K2 coal seam shows that the top and bottom portion of the coal seam have a lower content of REY than the middle portion. Goyazite and rhabdophane were identified with a scanning electron microscope equipped with an energy-dispersed X-ray spectrometer (SEM-EDX). The REY distributions through the coal seam, SEM-EDX data and the correlation analysis between ash yields and the concentrations have revealed that the REY mainly occurs in the organic matter. The K2 coal is a potential rare-metal resource due to its high REY contents, and the coal ash could be regarded as a new and promising raw material for recovery of REY as a by-product

Improved Diagnostics Using Polarization Imaging and Artificial Neural Networks

In recent years, there has been an increasing interest in studying the propagation of polarized light in biological cells and tissues. This paper presents a novel approach to cell or tissue imaging using a full Stokes imaging system with advanced polarization image analysis algorithms for improved diagnostics. The key component of the Stokes imaging system is the electrically tunable retarder, enabling high-speed operation of the system to acquire four intensity images sequentially. From the acquired intensity images, four Stokes vector images can be computed to obtain complete polarization information. Polarization image analysis algorithms are then developed to analyze Stokes polarization images for cell or tissue classification. Specifically, wavelet transforms are first applied to the Stokes components for initial feature analysis and extraction. Artificial neural networks (ANNs) are then used to extract diagnostic features for improved classification and prediction. In this study, phantom experiments have been conducted using a prototyped Stokes polarization imaging device. In particular, several types of phantoms, consisting of polystyrene latex spheres in various diameters, were prepared to simulate different conditions of epidermal layer of skin. The experimental results from phantom studies and a plant cell study show that the classification performance using Stokes images is significantly improved over that using the intensity image only

Polymer Composites Having Highly Dispersed Carbon Nanotubes and Methods for Forming Same

A method of forming carbon nanotube-polymer composites includes the steps of forming a mixture solution including a plurality of carbon nanotubes dispersed in a co-solvent. The co-solvent includes an organic solvent and a second solvent being a short chain fluorinated carboxylic acid having a boiling point below 150 degrees C which is less oxidizing than nitric acid, and is soluble in both the organic solvent and water. The first polymer is mixed with the mixture solution to form a polymer including mixture. The co-solvent is removed from the polymer mixture to form a dispersed nanotube-polymer composite. The second solvent can be trifluoroacetic acid

Polymer Composites Having Highly Dispersed Carbon Nanotubes

A carbon nanotube-polymer composite includes a polymer continuous phase having at least a first polymer and a plurality of carbon nanotubes dispersed in the polymer continuous phase. The carbon nanotubes are non-functionalized nanotubes. The carbon nanotubes are between 0.05 and 40 weight % of the composite. At least 98% of the carbon nanotubes are not involved in nanotube bundles