133 results about "Tortuous retinal vessels" patented technology

The invention discloses a nonionic aqueous polyurethane emulsion and a preparation method thereof, belonging to the technical field of high-molecular materials. The nonionic aqueous polyurethane emulsion comprises polyether polyol or polyester polyol, isocyanate, micromolecular chain extender, nonionic hydrophilic chain extender, hydrophilic chain extender, 0.6-1 weight portions of cross-linking agent, lower boiling point solvent, catalyst, amine neutralizer, amine chain extender, 0.4-2 weight portions of aqueous wetting agent, and aqueous levelling agent. The preparation method is characterized in that: prepolymerization, polymerization, emulsification, distillation, compounding are carried out to prepare the nonionic aqueous polyurethane emulsion, then the aqueous wetting agent and aqueous levelling agent are added with stirring to obtain an aqueous nonionic polyurethane glass fibre impregnating compound. The prepared nonionic aqueous polyurethane emulsion disclosed herein has the advantages of good stability, long stable phase, wide application scope, high strength, wear resistance, good elasticity, yellow stain resistance, aging resistance, solvent resistance, low temperature resistance, tortuosity resistance, good penetration, compatibility, good interface chemical combination or chemisorption and other excellent performances.

A method for measuring the effective diffusion coefficient and the porosity of a porous medium includes steps as follows: using an evaporation tube method to measure the binary gas diffusion coefficient DAB of component A in component B and the effective diffusion coefficient DABP of component A in the measured porous medium, utilizing the relation between DAB and DABP to work out the ratio epsilon/tau of the measured porous medium porosity to the tortuosity factor, and obtaining the porosity of the measured porous medium according to the tortuosity factor tau. The invention has the advantageof rapidly and accurately measuring the porosity of the porous medium and the effective diffusion coefficient of a gas in the porous medium, thereby providing conditions for chemical engineering and scientific research practice.

There is provided a non-aqueous-secondary-battery separator formed of a composite membrane including: a porous base material containing a thermoplastic resin; and a heat-resistant porous layer provided on one or both surfaces of the porous base material and containing an organic binder and an inorganic filler, in which the tortuosity rate of the composite membrane is from 1.5 to 2.0.

A computer system that segments a colon for a computed tomography colonography (CTC) is described. During operation, the computer system accesses imaging data having a spatial resolution. Then, the computer system identifies the colon lumen based on probabilities for different tissue classes in the imaging data. Moreover, the computer system segments the colon into subsegments based on an articulated object model that fits a tortuosity of the colon along a centerline of the colon, where the articulated object model includes values of an orthonormal basis set, curvature and torsion along the centerline, and where boundaries between subsegments are based on the curvature and die torsion. For example, a given boundary between a pair of subsegments may corresponds to or may be related to a minimum value of the curvature and a maximum value of the torsion over a length of the colon.

Permeability is one of the most important factors in influencing the commercial viability of a hydrocarbon reservoir. So far, permeability cannot be measured directly in-situ in reservoir formations. This invention relates to the field of estimating in-situ permeability of the reservoir rock formations. The measurements can be made across two wells or in a single well. Due to the morphology of their pore interconnections and the pore fluids in the rock, permeable rocks are elastically nonlinear. In a permeable rock, which is elastically nonlinear, the interactions between two elastic waves can be used in a unique way to map its physical properties. In this invention, the interaction of an elastic wave generated within the permeable rock with an externally generated seismic signal is used to determine the bulk tortuosity and bulk permeability of a reservoir rock formation.

A method for utilizing received formation data to determine one or more fluid instance such as reservoir wettability while in one of a subterranean environment or a surface environment. The method comprising: (a) obtaining at least one set of formation data wherein the set of formation data includes magnetic resonance data from two or more samples within an approximate common characteristic region in the reservoir; (b) computing from the at least one set of received formation data a first fluid instance of the one or more fluid instance using at least two mathematical variables from the group consisting of one of oil saturation, water saturation, T₁, T₂, diffusion coefficient, tortuosity from long time diffusion coefficient or some combination thereof; and (c) interpreting the computed first fluid instance as at least one wettability property between the fluids in a formation located in the subterranean environment and the formation.

The invention relates to a shale gas apparent permeability calculation method considering multi-factor influence, which comprises the following steps: (1) reconstructing a shale three-dimensional digital core based on a shale two-dimensional profile scanning electron microscope image by adopting a multi-point geostatistics method; (2) calculating the porosity, tortuosity and porous medium characteristic length of the shale three-dimensional digital rock core; and (3) calculating the gas permeability in the organic matter and inorganic matter of the shale. According to the method, the influenceof the pore structure, different pore types (organic matter pores and inorganic matter pores), adsorption and desorption, surface diffusion, gas slippage, stress sensitivity and critical property change in the shale gas reservoir on the gas flow capacity is fully considered, and the shale gas flow capacity under the conditions of different pore structures and gas reservoirs can be accurately predicted.

The invention relates to a method for improving a shaft system centering process for ship building. The method comprises the following steps of: boring holes on a screw shaft flange, a middle screw shaft flange, a middle shaft front flange and a host machine output end flange; adjusting the tortuosity and deviation of the screw shaft flange and the middle screw shaft flange and the tortuosity and deviation of the middle shaft front flange and the host machine output end flange; and connecting the host machine output end flange and the middle shaft front flange and connecting the middle screw shaft flange and the screw shaft flange through bolts, and the like. The method of the invention has the advantages of greatly shortening the working time of the shaft system after a ship is undocked, lowering the pressure of a dock mooring test and contributing to shortening the mooring test period of a dock of a company.

The effective ionic conductivity in a composite structure is believed to decrease rapidly with volume fraction. A system, such as a bipolar device or energy storage device, has structures or components in which the diffusion length or path that electrodes or ions must traverse is minimized and the interfacial area exposed to the ions or electrons is maximized. The device includes components that can be reticulated or has a reticulated interface so that an interface area can be increased. The increased interfacial perimeter increases the available sites for reaction of ionic species. Many different reticulation patterns can be used. The aspect ratio of the reticulated features can be varied. Such bipolar devices can be fabricated by a variety of methods or procedures. A bipolar device having structures of reticulated interface can be tailored for the purposes of controlling and optimizing charge and discharge kinetics. A bipolar device having graded porosity structures can have improved transport properties because the diffusion controlling reaction kinetics can be modified. Graded porosity electrodes can be linearly or nonlinearly graded. A bipolar device having perforated structures also provides improved transport properties by removing tortuosity and reducing diffusion distance.

A diffusion medium for use in a PEM fuel cell including a porous spacer layer disposed between a plurality of perforated layers having variable size and frequency of perforation patterns, each perforated layer having a microporous layer formed thereon, wherein the diffusion medium is adapted to optimize water management in and performance of the fuel cell.

A catheter includes a proximal portion and a distal portion, the distal portion including an arcuate portion. The catheter further includes a rotating portion, the rotating portion connecting the proximal portion and distal portion, the rotating portion including a first piece and a second piece, wherein the first piece and second piece create a snap fit. Methods of using the catheter include threading the inserted catheter through the vasculature and allowing the distal portion to freely rotate about an axis defined by the rotating portion responsive to any tortuosity in the vasculature.

A hydraulic fracturing system and method for enhancing effective permeability of earth formations to increase hydrocarbon production, enhance operation efficiency by reducing fluid entry friction due to tortuosity and perforation, and to open perforations that are either unopened or not effective using traditional techniques, by varying a pump rate and/or a flow rate to a wellbore.

A composition includes a set hydraulic binder; and a foaming agent and has a porosity ≧0.55; a flow resistivity between 10000 and 200000 N.s.m-4; a tortuosity between 1.2 and 3.4; a viscous characteristic length between 10 μm and 60 μm; a thermal characteristic length between 60 μm and 1000 μm; and a compressive strength of at least 0.30 MPa as measured by modified ASTM C472.

The invention provides a multilayer graphene quantum carbon-based semiconductor material prepared from a PI film, and a preparation method for the multilayer graphene quantum carbon-based semiconductor material. The preparation method comprises the steps of S1, taking the PI film as a raw material, performing polymer sintering at a first temperature, and removing H, O and N atoms to form a carbon precursor; and S2, adjusting the first temperature to a second temperature, and performing graphitization on the carbon precursor to form the multilayer graphene quantum carbon-based two-dimensional semiconductor material, wherein at least in the step S2, nano metal material doping is carried out to form quantum dots in multilayer graphene. The multilayer graphene quantum carbon-based two-dimensional semiconductor material prepared by the method adopts a hexagonal planar net molecular structure, is orderly arranged, and has flexibility, high tortuosity ratio, and quite low in-plane dispersity and degree of deviation; band gaps are formed through nano metal doping, and are controllable; and in addition, by adoption of the preparation method, the large-area, low-cost, large-batch and roll-to-roll continuous production can be realized.

The invention relates to a preparation method and applications in supported catalysts of a carrier type titanium dioxide ultrafiltration membrane. According to the preparation method, a ceramic membrane is used as the support body, the self-growing phenomenon of titanium dioxide particles at high temperature is utilized, a titanium dioxide ultrafiltration membrane layer with high flux and tortuosity is formed on the surface of the ceramic membrane support body through the interweaving of titanium dioxide nanorods and calcining, thus the tortuosity and loose degree of the membrane layer can be effectively increased; an enough space is provided for supporting catalysts on the basis of ensuring the retention capacity of the original ceramic membrane; and the overall functionalization of the ceramic membrane is realized, namely the ceramic membrane supporting of multiple catalysts is realized and the product can be used in the fields such as photocatalysis, catalytic ozonation, catalytic hydrogen peroxide oxidation and catalytic wet oxidation.

Novel or improved microporous battery separator membranes, separators, cells, batteries including such membranes, separators, or cells, and/or methods of making such membranes and/or separators, and/or methods of using such membranes and/or separators. In accordance with at least certain embodiments, an improved or novel battery separator for a secondary or rechargeable lithium battery may have low Electrical resistance of less than 0.95 ohm-cm², or in some cases, less than 0.8 ohm-cm². Furthermore, the inventive battery separator membrane may provide a means to achieve an improved level of battery performance in a rechargeable or secondary lithium battery based on a possibly synergistic combination of low Electrical resistance, low Gurley, low tortuosity, and/or a unique trapezoid shaped pore. In accordance with at least certain multilayer embodiments (by way of example only, a trilayer membrane made of two polypropylene layers with a polyethylene layer in between), the inventive microporous membrane or battery separator may have excellent onset and rate of thermal shutdown performance.

Disclosed is a separator for an electrochemical device including a porous polymer film, and a porous coating layer including at least one type of particles of inorganic particles and organic particles and binder polymer, the porous coating layer formed on one surface or both surfaces of the porous polymer film, wherein the porous polymer film has a structure in which multiple fibrils arranged parallel to the surface of the film are stacked in layers, and the fibrils are bound to each other to form a lamellar structure with a size from 130 to 200 nm and tortuosity of the porous polymer film is from 1.60 to 1.90, and an electrochemical device comprising the same.

A system and method for providing information regarding the tortuosity of a wellbore path is provided. The method includes receiving data from a plurality of survey stations of a wellbore survey. The method further includes determining a plurality of tortuosity parameter values for the wellbore path within a corresponding plurality of analysis windows, wherein each analysis window has at least one tortuosity parameter value.

The column according to the present invention provides greatly increased effective length and tortuosity, per unit length of column material, by providing a smooth or textured, tight radius helical channel or channels within a silica monolith. The capillary according to the present invention is useful in enabling fully automated massively parallel analyses, syntheses, separations and concentrations at reduced costs and higher speed as well as in immobilization, filtration, and miniaturization/acceleration/automation of classical instrumentation for practicality of general deployment in environmental threat monitoring and other applications.

The invention relates to a simulating and evaluating method for acidification of a carbonate heavy-oil reservoir. The simulating and evaluating method comprises the steps of i) sample preparation and parameter measuring: taking a rock core sample of an oil reservoir, performing oil washing on the rock core sample, and preparing an acidification simulating experiment rock core through replacing the rock core by crude oil; ii) linear flow acid-etching hole simulation and acidification evaporation: perform linear acidification on the acidification simulating experiment rock core, measuring various parameters, then scanning the rock core by means of a three-dimensional imaging analysis system, obtaining a three-dimensional digital picture of the acidification hole, and finally obtaining a tortuosity factor through analysis; and iii) radial flow acid-etching hole simulation and acidification evaluation: performing radial acidification on the acidification simulating experiment rock core by means of an acid solution, ending after radial breakthrough, scanning the cross section of the rock core by means of the three-dimensional imaging analysis system, and analyzing the obtained acid etching image for obtaining a fractal dimension.

Provided is a separator for a nonaqueous electrolyte battery including a composite membrane. The composite membrane includes a porous substrate that contains a thermoplastic resin and an adhesive porous layer that is provided on at least one side of the porous substrate and contains an adhesive resin. The difference between the Gurley number of the porous substrate and the Gurley number of the composite membrane is 75 sec/100 cc or less. The difference between the tortuosity of the porous substrate and the tortuosity of the composite membrane is 0.30 or less.