123 results about "Characteristic length" patented technology

A method to optimize the amperometric detection in a microsystem consists in limiting the detection to times when the diffusion layer (18-20) of the analyte to detect remains smaller than the microchannel (7) height. The charge detected during the second part of the amperometric measurement (which corresponds to the integral of the measured current over the corresponding time period) can also be considered so as to remove the contribution of the capacitive current and, when applicable, of the current resulting from the reduction or oxidation of the analyte molecules present in a recess above the electrode at the beginning of the detection. A microfluidic amperometric sensor for performing the method comprises at least one microchannel (7) having at least one electrode (15-17), integrated in one wall of the microchannel, and having a characteristic length or radius which is smaller than half the microchannel height.

A surface-enhanced Raman scattering method and apparatus to sequence polymeric biomolecules such as DNA, RNA, or proteins is introduced. The method uses metallic nanostructures such as, for example, spherical or cylindrical Au or Ag nanoparticles having characteristic lengths of 10-100 nm which when illuminated with light of the appropriate wavelength produce resonant oscillations of the conduction electrons (plasmon resonance). Electric field enhancements of 30-1000 near the particle surface resulting from such oscillations increase Raman scattering cross-sections by about 10⁶-10¹⁵ due to the E⁴ dependence of the Raman scattering, wherein the largest enhancements occur in the gap/junction between novel closely spaced structures as disclosed herein.

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.

Fluoroalkylsilane-treated metal oxide particles and a fluoroelastomeric binder are dispersed in a fluorinated solvent with a low boiling point and applied to a substrate via spray deposition. The spray deposition process rapidly produces a conformal coating that features low surface energy and surface topography with a large range of characteristic length scales and re-entrant curvature, thereby imparting superoleophobicity. The degree of superoleophobicity is readily adjusted by means of altering the ratio of particles to binder. The choice of particle and binder result in coatings with thermal stability for thousands of hours at temperatures up to 200 degrees Celsius as well as desirable mechanical characteristics.

The invention discloses a fiber bragg grating sensing system based on a narrow-band scanning light source and an operation method. In the system, one of narrow-band light wave laser beams which are outputted by a tunable laser and have periodical changeable wavelength is divided into N paths to be incident into N sensor channels; the FBGs (fiber bragg grating) with non-overlapping wavelength change range in each sensor channel are arranged from short wavelengths to long wavelengths, from near to far according to the characteristics; another path is entered to an etalon of a calibrating channel; reflected light of each sensor channel and transmission light of the etalon are accessed to FPGA (field programmable gate array) through photoelectric detectors and a signal processing circuit; the output end of FPGA is connected with an industrial personal computer; the control signal is accessed to the tunable laser. The operation method is as follows: the narrow-band laser scanned by the tunable laser periodically is accessed to each sensor channel, and reflected when the wavelength of the laser is identical to the characteristic length wave of certain FBG; another laser path is transmitted through the etalon; the two paths of laser are converted into electric signals to be accessed to the industrial personal computer, so as to obtain the FBG wavelength variation. The fiber bragg grating sensing system can continuously scan with real-time wavelength calibration precision up to 1 micro strain. The FPGA are parallel to collect and process the wavelength, so that the demodulation speed is high.

A method for forming bonded substrates includes providing a plurality of substrates, each of which having a top surface. A characteristic length for each of the plurality of substrates is determined by: determining a topographical profile of the top surface of the substrate from an interior portion to an edge portion along a radial direction, determining a highest point of the profile, and defining the characteristic length as a distance from the highest point to the edge portion. A first substrate and a second substrate are selected where at least one of the first or the second substrates has a characteristic length shorter than a predetermined length. The first substrate and the second substrate are brought into contact and form bonded substrates, with the top surface of the first substrate facing the top surface of the second substrate.

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.

A method of determining the wear of a flank of a cutter tool, in which the wear is determined by a general function calculating a characteristic length of the wear as a function of at least one variable that depends on time, is provided.

The invention provides a multi-frequency antenna which comprises a feeding end, a first grounding end, a second grounding end, a loop microstrip line, a low-frequency resonant element, a high-frequency resonant element and a parasitic microstrip line. The loop microstrip line is connected between the feeding end and the first grounding end. The low-frequency resonant element and the high-frequency resonant element are connected to the loop microstrip line. The parasitic microstrip line is in electrical connection with the second grounding end. The high-frequency resonant element comprises a first open-circuit microstrip line and a second open-circuit microstrip line. The low-frequency resonant mode is excited by the low-frequency resonant element. The high-frequency resonant element is used to excite the high-frequency resonant mode. The second open-circuit microstrip line is coupled with the low-frequency resonant element to reduce the electrical characteristic length of the low-frequency resonant element. The parasitic microstrip line is coupled with the first open-circuit microstrip line to increase the bandwidth of the multi-frequency antenna on the high-frequency frequency band. The multi-frequency antenna has the advantage of small size and can be used to receive signals of multiple frequency bands.

The invention discloses a convenient interactive eyeglass fitting method and device. According to the method and the device, disclosed by the invention, users can be subjected to determination on face width, pupil distance, visual acuity and the like at all times and places only under the assistance of a mobile phone/tablet computer/personal computer with a front camera and a screen, a reference object with known characteristic length, a network and the like, and three-dimensional vivid display of an eyeglass rack wearing effect based on real body information of the users is provided, so that the efficiency of eyeglass fitting is greatly increased, the disadvantages during online eyeglass shopping that accurate eyeglass fitting information cannot be provided and a wearing effect cannot be viewed are overcome, and thus, the convenient interactive eyeglass fitting method and the device are universal.

The invention includes a micro porous layer and a plurality of heat-transfer enhancing structures on a surface of the heat transfer tube in contact with the cold fluid. The heat-transfer enhancing structures have a height H that satisfies a relationship to a flow characteristic length D of 0.05>H/D≧0.01, and a relationship to an installation clearance L between the heat-transfer enhancing structures in a flow direction of 40<L/H≦300.

The invention relates to the field of fluid solid coupling prediction, and particularly relates to a fluid solid coupling dynamic characteristic prediction method for a pipeline system. The method comprises steps: according to attributes of each pipeline element in the pipeline system, the pipeline system is dispersed into a straight pipe element type, an elbow element type and a pipeline accessory element type; according to the types of the dispersed pipeline elements, a field transfer fluid solid coupling matrix or a point transfer fluid solid coupling matrix corresponding to each pipeline element is built; the dispersed pipeline system is recombined into a plurality of transfer matrix units, and according to the minimal pipe wall bending wave wavelength predicted by the pipeline system or a predicted upper limit frequency, the maximal characteristic length of the transfer matrix units is calculated; and fluid solid coupling dynamic characteristics at any position of the pipeline system are predicted. Problems of numerical overflow and an instable prediction result for the pipeline system fluid solid coupling dynamics can be eliminated, the prediction process is simple and convenient, programming calculation is facilitated extremely, and the prediction precision is high.

The invention relates to a method and a device for characterizing low-speed non-Darcy seepage characteristics of a dense oil deposit. The method comprises the following steps: obtaining a dense oil deposit rock core to obtain the porosity of the dense oil deposit rock core; determining a maximum pore diameter, a minimum pore diameter and an average pore diameter according to a rock core mercury injection curve; determining a pore fractal dimension by utilizing the rock core mercury injection curve; determining the average tortuosity by utilizing the porosity; determining the characteristic length of a capillary tube bundle model according to the porosity, the pore fractal dimension and the maximum pore diameter; obtaining a cross section area of the capillary tube bundle model by utilizing the characteristic length; determining an average tortuosity fractal dimension according to the average tortuosity, the characteristic length and the average pore diameter; obtaining a low-speed non-Darcy seepage model of the dense oil deposit by utilizing the average tortuosity fractal dimension, the maximum pore diameter, the minimum pore diameter, the cross section area, the characteristic length and the pore fractal dimension; obtaining the low-speed non-Darcy seepage characteristics of the dense oil deposit by utilizing the low-speed non-Darcy seepage model of the dense oil deposit.

The invention relates to a radiator heat exchange performance simulation method and system. The method comprises the following steps of: obtaining parameter information of a radiator, acquiring working condition point setting information of the radiator heat exchange performance wind tunnel test; calculating the hydraulic diameter of the substance participating in the heat exchange experiment under each working condition point; heat exchange feature length, a Reynolds number and a Prandtl number; the hydraulic diameter under each working condition point is calculated; heat exchange feature length, inputting the Reynolds number and the Prandtt number into a pre-constructed mathematical model for fitting the heat exchange power of the radiator related to fluid flow; the method comprises thesteps of obtaining a mathematical model of a radiator, obtaining fitting heat exchange power, obtained through calculation of the mathematical model, of the radiator under all working condition points, optimizing the mathematical model with the minimum error between the fitting heat exchange power and actually-measured heat exchange power as a solving target, and simulating the heat exchange powerof the radiator under the corresponding working condition points according to the optimized mathematical model. The accuracy of the simulation result of the heat exchange performance of the radiatorcan be remarkably improved.

The invention discloses a method for quantitative detection of indentation fracture toughness of a coating material. The method includes steps: 1) adopting a pressing head for applying pressure intensity P to the coating surface to form indentation and cracks; 2) determining a coating surface indentation modulus E, indentation hardness H and crack characteristic length c; 3) substituting the indentation modulus E, indentation hardness H, crack characteristic length c and the pressure intensity P into a formula as shown in the specification to obtain material indentation fracture toughness Kc.A method for quantitative assessment of indentation fracture toughness of the coating material can be created according to indentation cracking characteristics to provide basic data support for coating mechanical property design and environmental adaptability assessment.

A perforating ohmic contact to a semiconductor layer in a semiconductor structure is provided. The perforating ohmic contact can include a set of perforating elements, which can include a set of metal protrusions laterally penetrating the semiconductor layer(s). The perforating elements can be separated from one another by a characteristic length scale selected based on a sheet resistance of the semiconductor layer and a contact resistance per unit length of a metal of the perforating ohmic contact contacting the semiconductor layer. The structure can be annealed using a set of conditions configured to ensure formation of the set of metal protrusions.

The invention relates to a method for detecting oblique triangle in a digital image. The method comprises the following steps of: acquiring the image and inputting into a computer; computing the gradient of each pixel point; computing an edge graph of the image; computing the directional line of each edge point by using the gradient of each edge point on the edge graph; computing the characteristic length and the characteristic energy of each pixel point in the image to acquire a characteristic length allocation graph and a characteristic energy allocation graph of the image; detecting local maximum points on the characteristic energy allocation graph under the limitation of a threshold value; determining a set of edge points which form a triangle according to each local maximum point and the characteristic length corresponding to the local maximum point; grouping edge points for the triangular edge point set according to gradient directions; verifying and removing unreasonable triangular edge point sets by using grouping numbers; fitting a straight line for each group of edge points of the grouped triangular edge point sets; acquiring the vertex position of the triangle by intersecting straight lines; and finally outputting the vertex position information of the triangle. By the method provided by the invention, the triangle in the image can be exactly detected; and the method is easy to realize, does not need information relative to the given image and has higher computational efficiency compared with the conventional method.

The invention belongs to the field of computer vision and specifically relates to a space-time bone characteristic and depth belief network-based human body behavior identification method. According to the method, a bone sequence is obtained via a depth camera based on each motion; bone point time sequence characteristics are extracted from the bone sequence and comprise displacement characteristics, speed characteristics and acceleration characteristics of each bone point; a bone reference point is chosen, relative distance between each bone point and the bone reference point is calculated, space characteristics of a motion bone sequence is obtained, the bone point time sequence characteristics and the space characteristics of a motion bone sequence are subjected to clustering operation,a characteristic length is fixed, a global motion description operator is established and subjected to dimensionality reducing operation, and motion classification is finished based on cross validation and a classifier.

A method of forming bulk metallic glass engineering materials, and more particularly a method for forming coarsening microstructures within said engineering materials is provided. Specifically, the method forms ‘designed composites’ by introducing ‘soft’ elastic/plastic inhomogeneities in a metallic glass matrix to initiate local shear banding around the inhomogeneity, and matching of microstructural length scales (for example, L and S) to the characteristic length scale R_P (for plastic shielding of an opening crack tip) to limit shear band extension, suppress shear band opening, and avoid crack development.