48 results about "Kinetic diameter" patented technology

Disclosed is an electrocatalyst for fuel cells, in which a porous carbon material including pores having a diameter smaller than a kinetic diameter of carbon monoxide is used as a support body and contact probability between an activated metal and carbon monoxide is decreased, thereby preventing fuel cell performance from being degraded by carbon monoxide. The electrocatalyst is obtained by adsorbing 10-80 parts by weight of an activated metal to 20-90 parts by weight of a porous support body, characterized in that the porous support body has a total surface area of 200-2,500 m<2>/g including an outer surface thereof and an inner surface of pores thereof, and has a plurality of pores penetrating into an interior of the support body with an average diameter of 2-15 nm and a total volume of 0.4-2.0 m<3>/g, and the activated metal is alloyed with 20-95 at % of platinum and 5-80 at % of one metal selected from among Ru, Sn, Os, Rh, Ir, Pd, V, Cr, Co, Ni, Fe and Mn. As for such an electrocatalyst, carbon monoxide does not fundamentally come in contact with the activated metal adsorbed to the inner surface of the pores of the support body, thereby minimizing degradation of fuel cell performance, thus overcoming fuel-feeding problems.

A process for making cerium dioxide nanoparticles containing at least one transition metal (M) utilizes a suspension of cerium hydroxide nanoparticles prepared by mechanical shearing of an aqueous mixture containing an oxidant in an amount effective to enable oxidation of cerous ion to ceric ion, thereby forming a product stream that contains transition metal-containing cerium dioxide nanoparticles, Ce_1-xM_xO₂, wherein “x” has a value from about 0.3 to about 0.8. The nanoparticles thus obtained have a cubic fluorite structure, a mean hydrodynamic diameter in the range of about 1 nm to about 10 nm, and a geometric diameter of less than about 4 nm. The transition metal-containing crystalline cerium dioxide nanoparticles can be used to prepare a dispersion of the particles in a nonpolar medium.

A process for making cerium-containing oxide nanoparticles includes providing an aqueous reaction mixture containing a source of cerous ion, optionally a source of one or more metal ions (M) other than cerium, a source of hydroxide ion, at least one monoether carboxylic acid nanoparticle stabilizer wherein the molar ratio of said monoether carboxylic acid nanoparticle stabilizers to total metal ions is greater than 0.2, and an oxidant at an initial temperature in the range of about 20° C. to about 95° C. Temperature conditions are provided effective to enable oxidation of cerous ion to ceric ion, thereby forming a product dispersion of cerium-containing oxide nanoparticles, optionally containing one or more metal ions (M), Ce_1-xM_xO_2-δ, wherein “x” has a value from about 0.0 to about 0.95. The nanoparticles may have a mean hydrodynamic diameter from about 1 nm to about 50 nm, and a geometric diameter of less than about 45 nm.

The present invention discloses a method of preparing porous polymer microspheres by high voltage electrostatic anti-solvent process. Under the effect of high voltage electrostatic force, water-in-oil emulsion is discharged from an injection needle and is added dropwise to an anti-solvent. The organic solvent in the water-in-oil emulsion and the anti-solvent are miscible with each other, so that the polymer droplets takes the water emulsion droplets as nucleus and are cured and precipitated on surfaces of the nucleus, and the polymer microsphere structure containing pore-foaming agent water emulsion droplets is formed. The gas generated by ammonium hydrogen carbonate decomposition inside the microspheres because of emulsification opens holes on the surfaces of the polylactic acid microspheres to generate the porous structural microspheres. The present invention can be used for preparing drug carriers for inhaled pulmonary drug delivery. The experimental results show that: porous microspheres having a large geometric particle size can be prepared under ideal process parameters; the degree of sphericity is good, the surface is rough, the surface has a large number of pores of different sizes, and the interior is filled with through-hole structure; and increasing the input amount of ammonium hydrogen carbonate, the geometric particle size of the product can be significantly improved and the aerodynamic diameter can be reduced.

A system and method for locating magnetic material. In one embodiment the system includes a magnetic probe; a power module in electrical communication with the magnetic probe to supply current to the magnetic probe; a sense module in electrical communication with the magnetic probe to receive signals from the magnetic probe; and a processing module in electrical communication with the power module and the sense module. The processing module generates a waveform that controls the supply of current from the power module and receives a signal from the sense module that indicates the presence of magnetic material. The magnetic probe is constructed from a material having a coefficient of thermal expansion of substantially 10⁻⁶/° C. or less and a Young's modulus of substantially 50 GPa or greater. In one embodiment magnetic nanoparticles collect in the lymph nodes. In one embodiment the particles have a mean hydrodynamic diameter of between 5-200 nm.

A method is disclosed of treating a porous crystalline molecular sieve having a pore size less than or equal to about 5 Angstroms to decrease its coke selectivity in oxygenate to olefin conversion reactions. The method comprises contacting the molecular sieve with an acid having a kinetic diameter greater than or equal to that of acetic acid.

The invention belongs to the technical field of separation materials, relates to a preparation method of a zeolite molecular sieve and particularly relates to a gas separation material with a 'molecular gate' effect on CH4 and CO2. The separation material can be widely applied to separation and recovery of CO2 in natural gas. The preparation method includes: adjusting a silicon-aluminum ratio, and adopting a raw material mole ratio of SiO2/Al2O3 being 4.0-4.26 to obtain a ZK-5 molecular sieve; adding the molecular sieve into potassium salt solution, and heating and stirring for ion exchange while continuously adding distilled water in a heating process to keep the total quantity of the solution unchanged; after ion exchange, adopting deionized water for washing and filtering, and drying to obtain the K-ZK-5 zeolite molecular sieve. Due to changing of the silicon-aluminum ratio and K<+> introduction, the molecular sieve shows the 'molecular gate' effect, namely the molecular sieve only adsorbs CO2 small in kinetic diameter and is extremely low in adsorption quantity of large gas molecules such as CH4 and N2.

The invention discloses a test box for simulating the corrosion of a PM2.5 (particulate matter 2.5) polluted environment, which belongs to the technical field of material corrosion and reliability evaluation. The test box comprises a clean air supply device, a pollution source generating device, a particulate matter screening device, a sample corrosion test reaction device, a particulate matter collection device and a pollutant adsorption device. By adopting the test box, the PM2.5 pollution source is controlled, and the temperature-controlled, humidity-controlled and multi-path pollution source of the dynamics diameter of the PM2.5 pollution source can be controlled. The test box has the advantages that the floor occupation area is small, the structure is simple, convenience in operation is realized, the pollution is small, the temperature, the humidity and the pollution source are proportionally and simultaneously controlled, and the test box is applicable to the scientific research and the engineering test research.

The invention discloses a metal-organic framework MIL-160 film, a preparation method and an application, and belongs to the technical field of preparation of functional film separating materials. Themetal-organic framework MIL-160 film has excellent chemical stability and hydrothermal stability, the hole diameter of the film is about 0.6 nanometer, and the size of the hole diameter is equal to that of the dynamics diameter of a xylene homologue. According to the method, a porous aluminum oxide substrate is functionally modified through dopamine, polydopamine is modified on the surface of theporous substrate, MIL-160 particle 'capturing' and 'adsorbing' capacity of the surface of the porous substrate is enhanced, so that nucleating and growing of the MIL-160 film on the surface of the substrate are facilitated, and the uniform and compact MIL-160 film is prepared and has high separation performance. The MIL-160 film prepared by the method is used for separation of xylene geometric isomers, the xylene permeation flux of the film is 258-563g*m<-2>*h<-1>, and the p-xylene/o-xylene separation coefficient of the film is 16.8-38.5 at the pervaporation temperature of 25-100 DEG C.

The invention relates to a portable system for generating and conveying aerosol rich in negative oxygen ions and antioxidase, which comprises a battery, a negative ion generator, an atomizer (comprising a driving circuit and an ultrasonic atomization film), solution containing the antioxidase, a gas-mist mix suction nozzle and the like. The negative ion generator is connected with the atomizer in parallel. The negative ion generator uses a piezoelectric transformer to generate negative high pressure and is an electronic emission type negative ion generator, the working frequency of the ultrasonic atomization film is between 1.4 and 3.5 MHz and can make the kinetic diameter of atomized particles of the solution containing the antioxidase be between 0.5 and 15 microns and the atomized particles can be absorbed into a lung in a large amount. The electric power of the system is lower than 25 watts and the volume is less than 700 cubic centimeters so that the system is convenient to carry and use and can generate the aerosol rich in the negative oxygen ions and the antioxidase and beneficial for human body health for people to inbreathe to the lung.

A core-shell-structured composite molecular sieve material is formed in the way that based on the difference between the molecular kinetic diameters of carbon dioxide and nitrogen, through crystallization and ion exchange, a porous material which selectively allows carbon dioxide to penetrate but prevents other gases is built on the surface of a zeolite molecular sieve. Through building core-shell composite molecular sieve materials with different shell-layer thicknesses, and the shell-layer molecular sieve apertures are adjusted through ion exchange, while the excellent adsorption capacity of the original zeolite molecular sieve is maintained, the adsorption selectivity is carbon dioxide is improved.

The invention is directed to a method of stabilizing metalloaluminophosphate molecular sieves and catalysts derived therefrom. In particular, the invention is directed to a method of treating such molecular sieves with one or more nitrogen containing compounds having a kinetic diameter greater than the average pore size of the activated molecular sieve and selected from the group consisting of amines, monocyclic heterocyclic compounds, organonitrile compounds and mixtures thereof to chemisorbed and/or physisorbed the compound onto the molecular sieve. The compounds may be easily desorbed before or during use and after storage. The invention is also directed to formulating the molecular sieve into a catalyst useful in a process for producing olefin(s), preferably ethylene and/or propylene, from a feedstock, preferably an oxygenate containing feedstock.

Provided is an organic ligand-bound metal surface that selects one gaseous species over another. The species can be closely sized molecular species having less than 1 Angstrom difference in kinetic diameter. In one embodiment, the species comprise carbon monoxide and ethylene. Such organic ligand-bound metal surfaces can be successfully used in gas phase separations or purifications, sensing, and in catalysis.

The present invention is one kind of catalyst for producing low-sulfur and low-arene clean diesel oil and its preparation. The catalyst has modified Y-type molecular sieve as its acid component, andthe modification process of the molecular sieve is to make siliceous organic matter with relatively large dynamic diameter contact with the molecular sieve and combine with acid centers on the surface of the molecular sieve while maintaining the acid centers inside the molecular sieve pore passages of the molecular sieve under certain conditions. The catalyst is used in producing low-sulfur and low-arene clean diesel oil and has the advantages of high diesel oil yield, high cetane number of diesel oil product, low sulfur, nitrogen and arene content in diesel oil, etc.

The invention discloses an icariin sustained and controlled release nano-particle and a method for preparing the same. The method includes preparing icariin/PLGA (polylacticcoglycollic acid) solution and PVA (polyvinyl alcohol) solution; adding the icariin/PLGA solution into the PVA solution; uniformly mixing the icariin/PLGA solution and the PVA solution to obtain mixed solution and then emulsifying and treating the mixed solution; removing organic solvents by means of evaporating; centrifuging and washing the mixed solution; centrifuging and washing the mixed solution again; carrying out repeated operation to obtain the icariin sustained and controlled release nano-particle. The icariin sustained and controlled release nano-particle and the method have the advantages that the average hydrodynamic diameter of the icariin sustained and controlled release nano-particle prepared by the aid of the method ranges from 100 nm to 600 nm, the solubility of the icariin sustained and controlled release nano-particle in water is improved by 100 times at least as compared with icariin crude medicines, and the dispersibility of the icariin sustained and controlled release nano-particle can be obviously improved; icariin can be slowly released to prolong the action time, and accordingly the bioavailability and the efficacy of the sustained and controlled release nano-particle can be effectively improved; materials used in the method are simple and inexpensive, preparation procedures are easy and convenient to operate, and the method is good in repeatability.

The invention relates to a method for improving the catalytic selectivity of a supported catalyst and application thereof. When a catalyst support is a porous one, a poisoning agent of which the kinetic diameter is greater than the dimension of a support pore and a previously prepared supported catalyst are sufficiently stirred to react; and when the catalyst support is a non-porous one, a poisoning agent of which the kinetic diameter is greater than that of a target selective reactant and the previously prepared supported catalyst are sufficiently stirred to react, thereby obtaining the poisoned supported catalyst. According to the method, the catalytic activity of internal metal nanoparticles is retained by reducing the catalytic activity of metal nanoparticles on the external surface of the support; or the effect of improving the catalytic selectivity of the supported catalyst is achieved by screening the target reactant by means of the poisoning agent. The method can effectively improve molecular dimension selectivity or chemical reaction site selectivity in catalytic hydrogenation reaction of olefin.

A N-acylsarcosine modified water-base magnetic liquid used as magnetic carrier to separate cell, protein and gene is prepared through synthesizing and washing magnetic nanoparticles, and using N-acylsarcosine as tabilizer to prepare magnetic liquid.

A composition containing polydisperse aminodextran polymer molecules is soluble in an aqueous solution at a concentration of 10 mg/ml. The molecules therein have a narrow size distribution characterized by an average molecule mean hydrodynamic diameter of greater than 115 nm, a polydispersity index of between 0.10 and 0.47, an average molecular weight (MW) greater than 3 million daltons, and an amine content of greater than 50 amines per molecule. Similar soluble compositions contain the polymer molecules with an average MW of greater than 7 million daltons. These compositions are useful in forming reagents by conjugation with proteins for labeling cells. Methods of making these compositions and reagents from conventional mixtures of aminodextran polymers involve fractionation on column chromatography.

The invention discloses an icariin nanoparticle and a preparation method thereof. The preparation method includes preparing an icariin solution and a PVA solution, adding the icariin solution into thePVA solution, and performing emulsification after even mixing; collecting the mixed solution after emulsification, and evaporating an organic solvent; centrifuging a sample, washing sediments by purified water, performing centrifugation again, and repeating operations to wash the nanoparticle clean to obtain the icariin nanoparticle. The average fluid dynamics diameter of the obtained icariin nanoparticle is 100-400 nanometers. Compared with icariin crude drugs, the icariin nanoparticle has the advantages that water dissolving property of the icariin nanoparticle is improved by more than 10 times, and dispersing performance is also improved remarkably, so that biological utilization rate and medicinal effect of the icariin nanoparticle can be improved effectively. The preparation method does not need carriers, used materials are simple and cheap, the preparation process is simple and convenient to operate, and repeatability is high.

A process for the preparation of a dispersion of crystalline nanoparticles in an aqueous medium is disclosed. Specifically, a first solution comprising a substantially water-insoluble substance in a water-miscible organic solvent is rapid mixed with an aqueous phase comprising water, and optionally a stabilizer, to form a dispersion of amorphous particles. The dispersion of amorphous particles is then sonicated for a sufficient period to form crystalline nanoparticles of the substantially water-insoluble substance. The process provides nanocrystals with a mean hydrodynamic diameter of less than 1 micron, particularly less than 300 nm, and is particularly useful for the preparation of nanocrystalline dispersions of pharmaceutical substances.

The present invention discloses one kind of catalyst for producing low-freezing point clean diesel oil and its preparation. The catalyst has modified beta-zeolite as its acid component and the zeolite modifying process is to make siliceous organic matter with relatively dynamic diameter contact with zeolite in certain condition so that the organic matter is combined with the acid centers on the outer surface of zeolite to deactivate while maintaining the acid centers inside the pore passages of zeolite. The catalyst is used in producing low-freezing point clean diesel oil, and has the advantages of high yield and cetane number, low sulfur and nitrogen content and low low-freezing point of diesel oil product, etc.