38 results about "Unimodal distribution" patented technology

The invention discloses a polythene resin for tubing, a preparation method and a composition thereof. The mass flow rate of a polythene resin fusant is between 0.25 and 1.0 g/min; the density of the polythene resin fusant is between 0.930 and 0.955g/cm< 3 >; molecular weight of the polythene resin fusant is in unimodal distribution; the ratio of Mw to Mn is between 20 and 90; a comonomer is butylethylene; the branching degree is between 20 and 80/10,000C; and 6 LPL is more than or equal to 10.00MPa. The resin is produced through adopting a Unipol gas phase polythene process. The polythene resin composition for the tubing comprises the following compositions in weight portion: 100 portions of the polythene resin. 0.1 to 0.5 portion of antioxidant and 0 to 5 portions of pigment. The polythene resin and the polythene resin composition have high long-term hydrostatic strength and excellent capability for resisting slow crack expansion and rapid crack expansion.

The invention discloses a preparation method of a polycarbonate microporous material with bimodal distribution, aiming at solving the technical problem that the thermoplastic foam prepared by adopting the existing preparation method only has unimodal distribution or easily pollutes the environment. According to the technical scheme, the preparation method disclosed by the invention comprises the steps of: placing a polycarbonate sheet in CO2 fluid under a super-critical state to carry out saturation to obtain an even PC (polycarbonate)/CO2 mixture after being entirely saturated; carrying out first-time fast pressure relief within the time of 4-30 seconds, and keeping for 0.5-3 hours under the constant-temperature and constant-pressure state; carrying out second-time fast pressure relief within the time of 4-30 seconds, thus relieving the pressure in an autoclave to the atmospheric pressure; fast taking out the CO2 gas-containing polycarbonate sheet, transferring to a constant-temperature glycerol bath to carry out foaming; and finally, shaping the foamed polycarbonate sheet in an ice-water bath for 30 minutes to obtain the polycarbonate microporous material with bimodal distribution. The supercritical CO2 fluid used in the preparation method is low-cost, non-toxic and non-inflammable, and has no pollution to the atmosphere and water body, as well as no damage role to ozone sphere, thus being an environment-friendly physical foaming agent.

The present invention relates to a hybrid supported metallocene catalyst including at least first metallocene compound, at least one second metallocene compound, at least one cocatalyst compound, and a carrier, a preparation method therefor, and a polyolefin resin polymerized in the presence of the catalyst, wherein the second metallocene compound is a compound of a bridged structure having a ligand of an asymmetric structure, and the polyolefin resin has a density of 0.910 g/cm³ to 0.960 g/cm³, a molecular weight density in a unimodal distribution of 3 to 5, a melt index of 0.05 to 100 at 2.16 kg, and a melt flow rate of 20 to 40.

The invention relates to preparation for teeth material and nano zirconia powder material, which comprises: preparing zircon salt solution, ammonia and organic solution to prepare monodispersed ball nano powder, mixing, emulsifying, dispersing with ultrasonic wave, distilling, clearing, and calcining; using water/oil-soluble surfactant or organic solvent to encircle the microemulsion droplet as nano micro reaction system. This nano zirconia powder has particle size less 100nm and unimodal distribution.

The invention provides bimodal distribution nano-silver paste serving as a thermal interface material and a preparation method of the bimodal distribution nano-silver paste. The preparation method comprises the following steps of mixing small-grain-diameter nano-silver particles with grain diameters of 5-20 nanometers, large-grain-diameter nano-silver particles with grain diameters of 30-150 nanometers and ultra-pure water according to a certain mass proportion of 4:1-1:1; mechanically stirring the mixture; ultrasonically dispersing the mixture and centrifuging the mixture; and removing an upper layer of solution so as to obtain the bimodal distribution nano-silver paste. The invention also provides a preparation method for the small-grain-diameter nano-silver particles with the grain diameters of 5-20 nanometers and the large-grain-diameter nano-silver particles with the grain diameters of 30-150 nanometers. Compared with unimodal distribution nano-silver paste and tin-lead solder, the bimodal distribution nano-silver paste which is prepared by the method has high heat conduction performance and high sintering structural stability. The preparation method is simple, preparation technological conditions are stable and reliable, the environment cannot be polluted, and the bimodal distribution nano-silver paste can be used industrially.

A mat having a highly uniform porosity distribution is produced by consolidating 15 or more layers of melt blown webs (or the like) having different orientations. Control over the porosity is provided by using webs that exhibit a narrow, unimodal distribution of fiber diameters over the bulk of its distribution, such as in the top 80%. A compliance of the mats can be chosen by selecting a number and orientation of the webs. It is thus possible to produce mats that are good candidates for vascular grafts, for example. The uniformity of the porosity within the range of 6 μm to 30 μm permits seeding of the vascular graft with endothelial and smooth muscle cells. The mats have the demonstrated ability to retain, and support growth of, smooth muscle cells and endothelial cells.

The invention discloses preparation and application of styrene-conjugated diene copolymer containing active combined sulfur. A sulfur-containing silicane molecular structure is necessarily characterized in that A) the tail end of the sulfur atom is connected with the carbon atom; B) the polymerized sulfur appears in the molecule in the form of -Sn-, wherein n is in a range from 2 to 5; C) the molecule contains silicon bonds, such as -Si-R3, wherein R is alkoxy or halogen. The molecular ratio of the polymer tail end active lithium to the sulfur-containing silicane is (1-6):1, the average molecular weight of the polymer is 0.08-0.4 million, molecular weight distribution is in the form of unimodal distribution, molecular weight distribution index is 1-2.8, the mass content of the combined sulfur of the copolymer is 0.030-0.062%, the copolymer resin or the elastomer is high in strength, the copolymer crude rubber is low in cold fluidity and excellent in processability, and the vulcanized rubber is not reversed.

The invention relates to a method for preparing a mesoporous material from hydroxyapatite, relating to a method for preparing the mesoporous material and aiming to solve the problem that a mesoporous material, which is high in specific area, has the aperture of about 4.2 nm and is in unimodal distribution, cannot be prepared through an existing iron modified apatite mesoporous material preparation method. The method disclosed by the invention comprises the following steps of (1), preparing iron modified hydroxyapatite; and (2), washing and drying to obtain the iron modified hydroxyapatite mesoporous material. The mesoporous material prepared by the invention has the good property that aperture is distributed in a concentrated manner; the mesoporous material prepared by utilizing a high-concentration iron ion exchange method is 180-220 m<2>/g in specific area, about 4.2 nm in aperture, unimodal in distribution, good in reproducibility and dispersibility and high in yield; the method for preparing the mesoporous material from the hydroxyapatite, disclosed by the invention, is mainly used in the technical field of treatment of water-borne contaminants.

The invention belongs to the field of chemical crystallization technologies for drugs and particularly relates to a novel single febuxostat crystal form A and a preparation method thereof. According to the crystal form A provided by the invention, the grain size D50 is 16-25 microns, the grain size distribution curve of the crystal form A is of normal unimodal distribution, a preparation of the crystal form A has good dissolubility and a zero-deflection dissolution curve, and the bioavailability is high. The invention further provides the preparation method which can be used for preparing the single febuxostat crystal form A, and the yield reaches up over 86%; meanwhile, the preparation process is stable, the crystallization conditions are mild, and the volume of a consumed solvent is small, so that during industrial large-scale production, the production cost is reduced greatly, and the recovery and mechanical applying of the solvent are facilitated; the solvent is an aqueous solution containing ethanol and is non-toxic and harmless, so that the construction of an environmental-friendly and safe production environment is facilitated, and the preparation method is very suitable for industrial large-scale production.

The invention discloses a method for preparing colored toner used for laser printing and electrostatic copying. The invention combines with bulk polymerization, phase inversion polymerization, suspension polymerization technology and emulsion polymerization technology, and comprises the following steps: firstly, colorant and other additives are mixed with trace macromolecule, monomer and initiator completely for bulk polymerization for several hours, and aqueous phase solution which is dissolved with surfactant and dispersant is added to carry out the phase inversion and then polymerization is continuously carried out to obtain the product. The method obtains red, yellow and blue tricolor toner by polyreaction directly; the method has simple technology, less investment on equipment, energy saving and the uniform coloring of the product; and resin molecular weight shows bimodal distribution, thereby being good for fixation performance. The method overcomes the problem that unimodal distribution of the resin molecular weight causes poor fixation effect, uneasy even distribution of the colorant in the colored toner and over-wide particle size distribution during preparing the colored toner by the polymerization process.

The invention relates to a crystallization method for erythromycin ethylsuccinate with controllable crystal habit and particle size. The method comprises the following steps: 1) reacting erythromycin or salts thereof with ethyl succinoyl halide in a tetrahydrofuran solution, to obtain a reaction mixture containing erythromycin ethylsuccinate and tetrahydrofuran after the reaction is over; 2) under the stirring condition, adding water into the reaction mixture, and cooling until separation by crystallization; 3) filtering and drying to obtain erythromycin ethylsuccinate crystals. The key step is to control the stirring speed to be 250-400rpm and separation by crystallization is realized by adopting two-step program cooling mode, the obtained crystals are long rod-like crystal habits, with main particle size of 100-180mu m, and the particle size distribution shows unimodal distribution. The technology avoids the problems that the existing method causes the coalescence and uneven particle size distribution of erythromycin ethylsuccinate industrial crystallization products, and the quality is obviously improved.

The invention provides new types of plasmon-driven growth mechanism for silver nanostructures involving the fusion of triangular nanoprisms. This mechanism, which is plasmon excitation-driven and highly cooperative, produces bimodal particle size distributions. In these methods, the growth process can be selectively switched between bimodal and unimodal distributions using dual beam illumination of the nanoparticles. This type of cooperative photo-control over nanostructure growth enables synthesis of monodisperse nanoprisms with a preselected edge length in the 30-120 nm range simply by using one beam to turn off bimodal growth and the other (varied over the 450-700 nm range) for controlling particle size.

The invention discloses a binocular deep learning method based on adaptive single-peak stereo matching cost filtering. The method is characterized in that single-peak distribution supervision with real parallax as the center is directly applied to matching cost of network prediction, self-adaptive matching cost filtering is achieved. The method comprises the following steps that (1) a data set isconstructed, the data set comprises a left image and a right image, and the left image and the right image serve as a three-dimensional image pair; 2) taking the PSMNet as a stereo matching model basic network, inputting the stereo image pair into the PSMNet stereo matching model basic network, and outputting three matching cost bodies (Cost Volume) aggregated by the stacked hourglass 3D convolutional neural network by the PSMNet stereo matching model basic network; (3) for each matching cost body (Cost Volume), calculating the matching cost of each matching cost body (Cost Volume); the methodcomprises the following steps of: estimating a self-confidence degree graph by using a self-confidence degree evaluation network (Confidence Estimation Network) respectively, and adjusting a real matching cost volume (Group Truth Cost Volume) by using the self-confidence degree graph; the method comprises the following steps of: generating unimodal distribution of a pixel level to serve as a network training mark; the device has the advantages that the defects in the prior art can be overcome, and the structural design is reasonable and novel.

The invention discloses a method for detecting the non-unimodal distribution of measurement data, comprising the following steps: collecting measurement data capable of being detected; selecting a minimum data value, a second minimum data value, a median minimum data value, a median maximum data value, a second maximum data value and a maximum data value in the measurement data; making a first regression line for data between the minimum data value and the second minimum data value; making a second regression line for data between the median minimum data value and the median maximum data value; making a third regression line for data between the second maximum data value and the maximum data value; calculating the ratio Delta of a difference value between a maximum value and a median value to a difference value between the maximum value and a minimum value among an intersecting point x1 of the first regression line and an X-axis, an intersecting point x2 of the second regression line and the X-axis and an intersecting point x3 of the third regression line and the X-axis; and comparing the Delta with a detection critical value C alpha so as to confirm whether the measurement data is in non-unimodal distribution or not. The invention also provides a device for detecting the non-unimodal distribution of measurement data. The invention improves the accuracy of control in a counting process.

The invention discloses a PEI nano gel, which is prepared by the prepolymer solution of polyethylene imine on basic condition with pH value not more than 11 and radiation of ultraviolet light. The photon correlation spectrometry shows unimodal distribution for its particle size with dispesion coefficient 0.1-0.7. it also disloses its application as gene transfection carrier. The product has controllable particle size to decrease cytotoxicity and immunogenicity and increase its security and efficiency as carrier in biological medicine field.

The invention provides a yoghurt cup sheet raw material and a preparation method thereof. The yoghurt cup sheet raw material comprises the following components by weight: 6-7.5 parts of polybutadienerubber, 3-5 parts of mineral oil, 0.05-0.1 part of an antioxidant, and 87.4-90.95 parts of polystyrene. Specifically, the polybutadiene rubber has a particle size distribution of 1-8micron unimodal distribution. The yoghurt cup sheet raw material has a weight-average molecular weight of 19000-230000, impact resistance of 11-14kJ/m<2>, and tensile strength of 27-30Mpa. The yoghurt cup sheet raw material provided by the invention is HIPS with special strength properties, has good processability, rigidity and impact resistance, can be directly used as yoghurt packaging material, and has no need for adding rubber products, thereby further avoiding the phenomena of yellow spots and black spots caused by uneven mixing of rubber and HIPS.

The invention provides an image segmentation method during histogram approximate unimodal distribution of a scene. The method maximizes the difference between two types of mean values based on saturation characteristics, and comprises the following steps: firstly, converting an original image into an HSV color space and extracting saturation characteristic components; then, calculating an objective function through histogram distribution characteristics of saturation components, and finding the value of the maximized objective function to serve as the optimal segmentation threshold value to achieve binaryzation of the image; and finally, performing necessary morphological operation on the binarized image to obtain a final segmentation processing result. The invention aims to solve the problem of image segmentation when a histogram of a scene is approximately in single-peak distribution, provides a method for effectively segmenting two types of histograms when the histogram difference between a target object and a background is not obvious, and is good in robustness and stable and reproducible in result.