38 results about "Diffusion resistance" patented technology

The invention provides bionic fractal micro-channel reactor equipment for fluid fuel hydrogen production, which is particularly suitable for marine mobile hydrogen production scenes such as a ship power system and an offshore hydrogen refueling station. The microreactor adopts an upper, middle and lower layer functional structure design, and comprises a diversion diffusion area, a chemical reaction area and a product buffer collection area, the diversion diffusion area and the product buffer collection area are fractal tree-shaped microchannels with optimal continuous length ratio and mass diffusion flux, and the diffusion resistance of reactants can be remarkably reduced. By virtue of the characteristics of compact structure, vibration resistance and easiness in integration of the fractal microchannel, uniform distribution and efficient transportation of reactants are realized, heat and mass transfer performance can be enhanced under harsh working conditions of the ocean, and hydrogen production efficiency and system reliability are improved by combining efficient heat source supply and fuel conversion processes; and the requirements of an ocean mobile platform on efficient, compact and stable hydrogen production equipment are met.

The invention relates to the technical field of water treatment intelligent control, and discloses a biochar adsorption capacity dynamics simulation and prediction system, which comprises a data acquisition module, an Arrhenius equation is utilized to introduce a temperature correction coefficient to carry out thermodynamic compensation on an adsorption dynamics constant; the flow state recognition module judges a forward adsorption or reverse desorption working condition based on a Langmuir model; the resistance decoupling module is used for calculating a mass transfer Biot number based on a double-membrane theory so as to distinguish diffusion resistance in a liquid membrane and particles, and distinguishing physical blockage and chemical saturation by utilizing a physical blockage index; the lag compensation module introduces a lag correction factor to correct the desorption equilibrium concentration, and calculates the recovery adsorption capacity during the reverse desorption period; and the life prediction module corrects the theoretical residual capacity by using the dynamic utilization rate coefficient and generates an operation and maintenance instruction. According to the invention, through resistance decoupling and lag compensation mechanisms, physical and chemical attenuation mechanisms are effectively distinguished, and accurate prediction of the adsorption penetration time under the dynamic working condition is realized.

This invention discloses a method for hydrotreating catalytic cracking slurry. A fixed-bed hydrotreating process is employed, comprising: in the presence of hydrogen, the catalytic cracking slurry sequentially contacts a hydrotreating protectant, a hydrotreating transition catalyst, and a hydrodesulfurization catalyst to undergo a hydrotreating reaction, yielding hydrotreated oil. The hydrotreating protectant comprises an alumina support with a most probable pore size of 40–100 nm, molybdenum oxide, and cobalt oxide. The hydrotreating transition catalyst comprises an alumina support containing additives and MoO3 and CoO. The support has a bimodal pore size distribution, with smaller pores concentrated in the 10–40 nm range and larger pores concentrated in the 150–400 nm range. This method eliminates the diffusion resistance during the adsorption and reaction of large molecules on the catalyst surface during the hydrotreating of catalytic cracking slurry, increases the capacity for more deposits such as coke, extends the operating cycle of the unit, and facilitates hydrodesulfurization and other reactions. It also increases the content of tricyclic and tetracyclic aromatics in the hydrotreated oil, making it a high-quality feedstock for needle coke production.

The protective transportation device for the medical radiopharmaceuticals comprises a protective barrel, a protective cover and a plurality of adsorption assemblies arranged in the protective barrel, storage grooves are formed among the adsorption assemblies, the adsorption assemblies are distributed in the circumferential direction of an inner cavity of the protective barrel at equal angles, and the radial sections of the adsorption assemblies are each of a 90-degree fan-shaped structure; each adsorption assembly comprises a plurality of splicing frames, every two adjacent splicing frames are tightly attached, circulating holes are formed in the circumferential outer walls of the splicing frames, the multiple adsorption assemblies distributed in the circumferential direction at equal angles are arranged in the protection barrel, the radial section of each adsorption assembly is of a 90-degree fan-shaped structure, and the multiple adsorption assemblies are formed by stacking the multiple splicing frames; the circulation holes of the adjacent splicing frames are formed in a staggered mode to form a continuous snake-shaped airflow channel, the structure remarkably prolongs the escape path of radioactive gas, the gas is forced to undergo multiple times of steering and diffusion resistance when passing through the multiple adsorption layers, and therefore the leakage risk is effectively reduced.

The invention belongs to the technical field of catalyst carriers, and particularly relates to an alumina carrier as well as a preparation method and application thereof. The specific surface area of the alumina carrier is 250m / g-470m / g, the pore volume of the alumina carrier is 1.0 mL / g-3. 3mL / g, the content of pores with the pore diameter larger than 100nm in the alumina carrier is larger than or equal to 15%, and the strength of the alumina carrier is larger than 5N / mm. The alumina carrier has the beneficial effects that the pore volume ratio of macropores of the alumina carrier reaches 15% or above, so that the in-particle diffusion limitation of the catalyst is effectively relieved, and the alumina carrier is particularly suitable for treating high-diffusion resistance systems such as macromolecules, heavy oil, asphaltene and coal tar; according to the present invention, the pore structure of the alumina carrier has strong adjustability, and by matching the type and the amount of the demulsifier with the auxiliary pore-enlarging agent, the 200-3500 nm macropore regulation can be flexibly achieved so as to meet different hydrogenation reaction requirements; the alumina carrier provided by the invention is high in mechanical strength, even though the pore volume is large and diffusion macropores are rich, the prepared alumina carrier still has the single grain strength of greater than or equal to 5N / mm, and meets the requirements of an industrial fixed bed hydrogenation device.

To prevent the influence of the dynamic pressure of gas to be measured on a pump cell.SOLUTION: A sensor element is to detect the concentration of specific gas in gas to be measured and comprises a diffusion rate determination unit that applies diffusion resistance to the gas to be measured introduced from a gas introduction port. The diffusion rate determination unit has a first space part 85a that allows the gas to be measured to pass through in a fore-and-aft direction. The shape of a cross section orthogonal to the fore-and-aft direction in at least part of the first space part 85a in the fore-and-aft direction is a predetermined shape with a longer outer periphery than a reference rectangle S1. The reference rectangle S1 is a rectangle having the same area as the cross section of the first space part 85a and is obtained by deforming a circumscribed rectangle R of the cross section formed of two sides parallel in the vertical direction and two sides parallel in the transverse direction orthogonal to the vertical direction, so as to reduce the length of the short sides while maintaining the length of the long sides.SELECTED DRAWING: Figure 6

The application relates to a gas detection device and a gas concentration detection method. The gas detection device comprises a micro-detection chamber, a power source, an air outlet, a gas diffusion resistance element, and a working electrode. The volume of the micro-detection chamber is fixed, and the micro-detection chamber is provided with an air inlet. The power source is connected with the micro-detection chamber. The air outlet is connected with the power source. The gas diffusion resistance element is arranged in the micro-detection chamber. The working electrode is connected with the gas diffusion resistance element, and the working electrode is provided with a catalytic material. The working electrode is used for detecting a response value of a to-be-detected gas concentration and / or consuming the to-be-detected gas. The gas detection device has a small volume and a simple structural design. When the gas concentration is detected, a small amount of gas is required. According to specific experimental requirements, the gas detection device with different structural features can be used for measuring a single gas concentration or a mixed gas concentration.

The application relates to the technical field of intelligent water treatment control, and discloses a system for simulating and predicting the kinetics of the adsorption capacity of biochar, which comprises the following modules: a data acquisition module uses the Arrhenius equation to introduce a temperature correction coefficient to perform thermodynamic compensation on adsorption kinetic constants; a flow state recognition module determines a forward adsorption or reverse desorption working condition based on the Langmuir model; a resistance decoupling module calculates the mass transfer Biot number based on the double membrane theory to distinguish the liquid film and the internal diffusion resistance of the particles, and uses a physical blockage index to distinguish physical blockage and chemical saturation; a hysteresis compensation module introduces a hysteresis correction factor to correct the desorption equilibrium concentration and calculate the recovery adsorption capacity during the reverse desorption; and a service life prediction module uses a dynamic utilization rate coefficient to correct the theoretical residual capacity and generate operation and maintenance instructions. Through the resistance decoupling and hysteresis compensation mechanisms, the physical and chemical attenuation mechanisms are effectively distinguished, and the precise prediction of the adsorption breakthrough time under dynamic working conditions is realized.

The invention provides a sensor element and a gas sensor, which can suppress the influence of the dynamic pressure of the measured gas on a pump unit. The sensor element is a sensor element for detecting the concentration of a specific gas in the gas to be measured, and has a diffusion rate control unit for applying diffusion resistance to the gas to be measured introduced from the gas introduction port. The diffusion velocity control unit has a first space section (85a) through which the gas to be measured flows in the front-rear direction. The shape of a cross-section orthogonal to the front-rear direction of at least a portion of the first space section (85a) in the front-rear direction is a predetermined shape in which the length of the outer periphery is longer than the reference rectangle (S1). The reference rectangle (S1) is a rectangle obtained by deforming a circumscribed rectangle (R) having the same area as the cross section of the first space section (85a) and comprising two sides parallel to the up-down direction and two sides parallel to the left-right direction orthogonal to the up-down direction so that the length of the long sides is maintained and the short sides are shortened.

This invention relates to a method for modeling the curing kinetics of polymer resins, specifically providing a method for fitting the curing kinetics of polymer resins based on a segmented model. The method employs a three-stage segmented kinetic model. In the first stage, an external catalytic model is introduced to quantify the inductive acceleration effect of the co-catalyst in the early stages of the reaction. In the second stage, the Kamal-Sourour model is used to ensure the fitting accuracy of the chemical control region. In the third stage, a diffusion correction term based on thermodynamic evolution is introduced to quantify the diffusion resistance caused by entering the glassy state in the later stages, significantly improving the fitting accuracy at the end of curing. More importantly, this invention creatively proposes a method based on the activation energy minimum point. α tr and dynamic glass transition point α vit The segmentation points effectively couple the external catalytic model, the Kamal-Sourour model, and the dynamic diffusion model, effectively solving the problem of inaccurate fitting of the full-cycle kinetics, improving the fitting accuracy, and providing data support for the fine-tuning of the curing process.

The sensor element includes a diffusion control section that provides the measurement-object gas introduced from the gas inlet with diffusion resistance, wherein the diffusion control section includes a space portion through which the measurement-object gas is caused to flow in the first direction, a shape of a cross-section perpendicular to the first direction in at least a part of the space portion in the first direction is a predetermined shape with a longer outer circumference than a reference rectangle, and the reference rectangle is a rectangle that has the same area as the cross-section of the space portion, and the reference rectangle is a rectangle that is formed by deforming the circumscribed rectangle of the cross-section, which is composed of two sides parallel to the layered direction and two sides parallel to a second direction that is perpendicular to the layered direction.

A sensor element serves to detect the concentration of a specific gas in a sample gas. The sensor element comprises an element body that has an internal sample gas flow section, which introduces the sample gas from a gas inlet and causes the sample gas to flow in a front-to-back direction, and a diffusion control section 11a located in the sample gas flow section, which exerts a diffusion resistance on the sample gas introduced from the gas inlet. The diffusion control section 11a comprises a first porous body 87a and a first spatial section 85a, which are provided in at least a portion of the diffusion control section 11a in the front-to-back direction.The first porous body 87a is provided such that it occupies part of a cross-section of the diffusion control section 11a perpendicular to the front-back direction and allows the gas of the object to pass through it, and the first space section 85a comprises part of the cross-section that is not occupied by the porous body 87a and allows the gas of the object to pass through it.

The invention discloses a method for preparing durene by utilizing unsym-trimethylbenzene and methanol, which comprises the following steps: mixing unsym-trimethylbenzene, methanol and hydrogen, heating and gasifying, feeding into a fixed bed reactor, and carrying out alkylation reaction through a molecular sieve catalyst with hierarchical pore distribution to prepare durene, after a reaction product flowing out of the alkylation reactor is subjected to gas-liquid separation and oil-water separation, liquid-phase hydrocarbon components enter a rectification separation system, and light hydrocarbon with the carbon number of C6 or below, methylbenzene, xylene, trimethylbenzene, tetramethylbenzene and aromatic hydrocarbon fractions with the carbon number of C11 or above are separated out. The mesoporous channel of the catalyst increases the contact probability of the raw material and the active site of the molecular sieve, promotes the playing of the activity of the catalyst in a fixed bed, reduces the diffusion resistance of the raw material and the product, promotes the rapid diffusion of the product, and reduces the occurrence of side reactions, so that the conversion rate of unsym-trimethylbenzene and the selectivity of durene are improved; therefore, high durene yield can be obtained.

The invention discloses a catalyst for improving an octane number in light naphtha isomerization and a preparation method of the catalyst. The catalyst comprises 40-70wt% of a carrier, 5-15wt% of a dispersing agent, 15-25wt% of a pore forming agent and 8-20wt% of transition metal, wherein the transition metal is based on the oxide thereof. The two active centers of the ZSM-5-5at-ZrO2 composite molecular sieve catalyst cooperate to catalyze cracking and alkylation, and due to the mesopores of the shell, the diffusion resistance is reduced, and the diffusion of reactants and products is accelerated, so that the ZSM-5-5at-ZrO2 composite molecular sieve catalyst has the characteristics of good accessibility of the catalytic active centers, high catalytic activity, good stability and the like.

The application provides a fuel cell water management fault diagnosis method and system. The method comprises the following steps: controlling the on-off of the output current of the fuel cell by using DC / DC, periodically recording the voltage change before and after the current interruption, and processing the step data of the voltage response and the relaxation data of the voltage response; calculating the ohmic resistance according to the step data of the voltage response; calculating the diffusion resistance coefficient according to the relaxation data of the voltage response; judging the dry-wet state inside the fuel cell through the ohmic resistance and the diffusion resistance coefficient; and adjusting the operation parameters in real time according to the dry-wet state inside the fuel cell, so that the fuel cell can keep the best working state. The system comprises a data acquisition unit, an ohmic resistance calculation unit, a diffusion resistance coefficient calculation unit, a dry-wet state judgment unit and a central control unit. The application realizes the real-time feedback of the dry-wet state inside the fuel cell by periodically monitoring the change of the ohmic resistance and the diffusion resistance coefficient inside the fuel cell.

The present application provides a gas sensor that can suppress deterioration of measurement accuracy even when contaminated gas is generated on the reference gas space side. A housing of a gas sensor that has a reference gas space inside is provided with: an outer cylinder, one end portion side of which protrudes into the outer cylinder on the other end portion side of a sensor element that has a monitoring portion; and a sealing member, which is embedded in the end portion of the outer cylinder, seals the reference gas space. The sensor element is provided with: a first electrode lead portion, which has a first electrode through portion for electrically connecting the outside and at least one inside electrode and a first through portion insulating layer that covers the first electrode through portion; and a second electrode lead portion, which has a second electrode through portion that can electrically connect the outside and a measurement electrode and a second through portion insulating layer that covers the second electrode through portion. In a case where a diffusion resistance of the first electrode lead portion is set to A (cm －1 ) and a diffusion resistance of the second electrode lead portion is set to B (cm －1 ), A / B < 1.00.

Gas sensor for detecting the concentration of a specific gas in a gas of a measuring object, wherein the gas sensor comprises: a sensor element that an element body comprising an oxygen ion-conducting solid electrolyte layer, wherein a sample gas flow section is arranged in the element body, which allows the sample gas to be introduced into and flow through it, a measuring electrode that is arranged in the gas flow section of the object being measured, a device-gas-side electrode that is arranged inside or outside the element body in such a way that it comes into contact with the device gas, a reference electrode located inside the element body, and comprising a reference gas introduction section which allows a reference gas to be introduced into it and to flow through it to the reference electrode, the reference gas being used as a reference for detecting the concentration of a specific gas in the gas of the object being measured; a detection device which detects the concentration of a specific gas in the gas of the object being measured based on a voltage between the reference electrode and the measuring electrode; and a reference gas regulating device which allows an oxygen pumping current to flow between the reference electrode and the device gas-side electrode for pumping oxygen into the environment of the reference electrode from the environment of the device gas-side electrode, wherein a ratio R1 / R2 of a reaction resistance R1 of the reference electrode to a diffusion resistance R2 of the reference gas introduction section is greater than or equal to 0.1 and less than or equal to 2.0, wherein the reaction resistance R1 of the reference electrode correlates with the amount of oxygen to be pumped from the environment of the device gas-side electrode into the environment of the reference electrode, and the diffusion resistance R2 of the reference gas introduction section correlates with the probability that the oxygen in the environment of the reference electrode will be released to the outside.

The patent application relates to a paper-based packaging material with a carrier paper and a first coating arranged indirectly on at least one side of the carrier paper, wherein the first coating is a barrier layer and has an increased diffusion resistance to at least one substance selected from a group comprising fluid, gas, air, oxygen, carbon dioxide, nitrogen, inert gas, odorant, aromatic substance, water vapor, liquid, water, water-fat emulsion, fat, oil, mineral oil, and edible oil, odorant, flavorant, water vapor, liquid, water, water-fat emulsion, grease, oil, mineral oil, and edible oil individually or in combination, wherein the first coating is disposed between the carrier paper and a visually perceptible surface coating and directly contacts the surface coating. Furthermore, the invention relates to a package made of such a paper-based packaging material and a method of manufacturing the same.

The application discloses a method for improving the uniformity and stability of diffusion resistance, which adopts the furnace tail gas inlet and the furnace mouth gas extraction mode, and the process gas flows from the furnace tail to the furnace mouth; the boat support uniform flow plate and the quartz boat are sequentially placed on the quartz boat support; a plurality of small holes are arranged on the boat support uniform flow plate in sequence; and the furnace inner uniform flow plate is placed at the position close to the gas outlet of the gas inlet pipe at one end of the furnace cavity. The furnace inner uniform flow plate is placed at the position close to the gas outlet of the gas inlet pipe, the process gas is more uniformly dispersed when passing through the furnace inner uniform flow plate, the process gas flow can be more uniformly contacted with the silicon wafer, the influence of the gas flow on the process is avoided, and the uniformity and stability of the diffusion resistance can be greatly improved.

The invention provides a sensor element and a gas sensor, which can suppress the influence of the dynamic pressure of the measured gas on a pump unit. A sensor element for detecting the concentration of a specific gas in a gas to be measured, the sensor element being provided with: an element main body in which a gas-to-be-measured flow section is provided, the gas-to-be-measured flow section allowing the gas to be measured to be introduced from a gas introduction port and allowing the gas to be measured to flow in the front-rear direction; and a diffusion rate control unit (11a) that applies diffusion resistance to the gas to be measured introduced from the gas introduction port in the gas-to-be-measured circulation unit. The diffusion rate control unit (11a) has, in at least a portion in the front-rear direction, a first porous body (87a) that is provided so as to occupy a portion of a cross-section orthogonal to the front-rear direction and through which the gas to be measured can pass; and a first space section (85a) that includes a portion of the cross-section that is not occupied by the first porous body (87a) and through which the gas to be measured can pass.

The utility model provides a grinding device for preparing a diffusion resistance test sample. The grinding device for preparing the diffusion resistance test sample comprises a grinding disc and a pressure adjusting mechanism, the middle area of the grinding disc is a sample grinding area. The pressure adjusting mechanism is arranged above the grinding disc, the projection of the pressure adjusting mechanism on the grinding disc is located in a sample grinding area of the grinding disc, the pressure adjusting mechanism comprises a plurality of pressure applying heads with different weights, a grinding rod and a grinding head, and the grinding rod is arranged over the sample grinding area of the grinding disc. The grinding head is arranged at the end, close to the grinding disc, of the grinding rod, and the pressing head is detachably installed at the end, away from the grinding disc, of the grinding rod. The problem that the grinding pressure of the grinding device is not accurately adjusted can be effectively solved, and the uniformity and high quality of the surface of a sample are ensured.

A sensor element for detecting a specific gas concentration in a measurement-object gas includes: an element body provided with a measurement-object gas flow section therein, the measurement-object gas flow section introducing the measurement-object gas and causing the measurement-object gas to flow therethrough; a reference electrode disposed inside the element body; and a reference-gas introduction section that causes a reference gas to flow to the reference electrode, wherein the reference-gas introduction section has a reference-gas flow path, and one or more preliminary chambers which are disposed in a middle of the reference-gas flow path, and have a diffusion resistance lower than a diffusion resistance of the reference-gas flow path, and at least part of the reference-gas flow path is composed of a porous body so that any of the one or more preliminary chambers does not directly communicate with an outside of the element body.

And the anti-back-seepage property and the diffusivity are simultaneously improved by using a simple structure. The problem is solved by: an absorbent article provided with an absorbent material (50) having an absorbent body (56) that includes a crotch section (M) and is provided within the front and rear LD ranges, and a wrapping sheet (58) that wraps the absorbent body (56), the absorbent body (56) being formed by mixing and aggregating pulp fibers and highly absorbent polymer particles; the absorbent material (50) is provided with a plurality of high-compression parts (51) compressed in the thickness direction (TD) at intervals so as to be recessed from the surface of the absorbent material (50) into the absorbent body (56), portions other than the high-compression parts (51) in the region where the plurality of high-compression parts (51) are arranged are non-high-compression parts (52) which are thicker than the high-compression parts (51) and have a lower density, and the density of the absorbent body (56) in the high-compression parts (51) is 60000-250000 g / m3. And the area of each high compression part (51) is 2-200 mm < 2 >.

The application provides an etching-induced defect FeSe-sepiolite composite material and a preparation method and application thereof, and belongs to the technical field of industrial flue gas purification. A selenium source, a reducing agent, an iron source and a surfactant are mixed, etched FeSe is prepared through a hydrothermal reaction-acid etching treatment, and then is mechanically ball milled with sepiolite to obtain the etching-induced defect FeSe-sepiolite composite material. In the composite material, FeSe serves as an active substance, can inhibit the organicization and re-release of mercury from the root due to the antagonism between Hg and Se, and reduces the risk of secondary pollution; sepiolite has a natural fibrous structure, can provide an efficient mass transfer channel, reduces the diffusion resistance of Hg 0 , and simultaneously strengthens the interface bonding between FeSe and sepiolite by means of the shear force generated by mechanical ball milling, so that the structural stability of the adsorbent and the resistance to flue gas scouring are improved.

This application discloses a two-dimensional polymer thin film based on reactive diffusion theory, its preparation method, and its applications. The film exhibits a typical bilayer structure: the lower layer is a continuous and dense covalent organic framework substrate film with good crystallinity; the upper layer is a cyclic / honeycomb Turing structure formed by the orderly assembly of nanoparticles, exhibiting strong periodicity and high uniformity. The preparation method employs gas-liquid interface reactive diffusion: the monomer is dissolved in a mixed solvent of DMF and chlorobenzene, and acetic acid is used as a catalyst, which is then dropped onto the surface of deionized water. By controlling the monomer concentration (5 mg / mL), molar ratio (2:3), drop volume (15 μL), and diffusion resistance, the Turing structure can be precisely controlled. This invention features a mild process, can be used for large-area preparation, and produces thin films with regular structures and excellent stability. It can be directly applied to flexible electronics, membrane separation, sensing, and catalysis, effectively solving the technical bottlenecks of uncontrollable morphology, low crystallinity, and difficulty in large-scale production of traditional two-dimensional polymer thin films.

The application provides a grid-shaped porous structure carbon-supported nickel oxide applied to supercapacitors and a preparation method thereof, and belongs to the technical field of material preparation. ‑1 The specific capacitance of the compound is 1320-1630 F / g under 1 Ag ‑1 The rate performance is 70.2%-76% under 20 Ag The method first performs pore making on the solid spherical Ni-MOF through a salt template method, obtains urchin-shaped porous structure Ni-MOF precursors in a reaction, then performs annealing on the urchin-shaped porous structure Ni-MOF precursors in air, and obtains the grid-shaped porous structure carbon-supported nickel oxide NiO2@C. The preparation method is simple, environment-friendly and low in cost. The grid-shaped porous structure carbon-supported nickel oxide NiO2@C can increase the specific surface area of the material, provide sufficient electroactive centers, reduce the diffusion resistance between the electrode and the electrolyte, and promote the charge transmission in the electrochemical reaction process, and meanwhile, the material has a skeleton connected with each other, so that the electrochemical performance of the material is improved.

The application discloses nitrogen-doped high-entropy alloy powder and a preparation method thereof. In order to solve the problems of low gap nitrogen solid solubility, easy precipitation of brittle metal nitride and uneven composition in the existing physical nitriding technology, the application adopts anhydrous metal halide, alkali metal amide and alkali metal azide as a reaction precursor. In the process of closed heating reaction, the amide is melted to provide a continuous liquid phase mass transfer medium; the azide is decomposed to release alkali metal and local high-pressure nitrogen gas; the alkali metal drives the metal halide to co-reduction; in the initial stage of nucleation and growth, the multi-component metal atoms are combined with the amino free radicals and high-pressure nitrogen gas in the system to directly embed nitrogen atoms into the lattice gap position, and high-concentration in-situ solid solution doping is completed. The application avoids the diffusion resistance of gas molecules in the traditional gas-solid nitriding, and realizes the preparation of alloy powder with high purity, uniform phase and no precipitation of brittle metal nitride.

The invention discloses a (Cr / CrNb) / CrNb composite structure coating with high-temperature steam oxidation resistance and diffusion resistance, the composite structure coating comprises a Cr / CrNb transition layer deposited on the surface of a zirconium alloy substrate and a CrNb alloy coating deposited on the surface of the Cr / CrNb transition layer, and the CrNb alloy coating is composed of nanocrystals with the particle size of 500-800 nm; the invention further discloses a preparation method of the composite structure coating. According to the coating with the composite structure, the CrNb alloy coating with the Nb element with stable chemical properties and good compatibility is selected, the characteristic that the Nb element tends to be segregated at the interface of the coating and the substrate is utilized, mutual diffusion of Cr atoms and Zr atoms is greatly inhibited, the stability of the interface is kept, and the coating is suitable for preparing the nuclear reactor fuel cladding material.

To prevent the influence of the dynamic pressure of gas to be measured on a pump cell.SOLUTION: A sensor element is to detect the concentration of specific gas in gas to be measured, and the sensor element comprises: an element body provided therein with a gas-to-be-measured circulation part that introduces the gas to be measured from a gas introduction port and circulates the gas in a fore-and-aft direction; and a diffusion rate determination unit 11a that is provided in the gas-to-be-measured circulation part and applies diffusion resistance to the gas to be measured introduced from the gas introduction port. The diffusion rate determination unit 11a has, in at least part of the fore-and-aft direction, a first porous body 87a that is provided to occupy part of a cross section orthogonal to the fore-and-aft direction and allows the gas to be measured to pass through, and a first space part 85a that includes a portion of the cross section not occupied by the first porous body 87a and allows the gas to be measured to pass through.SELECTED DRAWING: Figure 5

The invention relates to the technical field of protective coatings, in particular to a high-temperature corrosion and erosion resistant composite coating on the surface of a gamma-TiAl-based alloy and a preparation method of the high-temperature corrosion and erosion resistant composite coating. The high-temperature corrosion and erosion resistant composite coating is prepared on the surface of a gamma-TiAl-based alloy matrix by adopting a vacuum physical vapor deposition method, and consists of a TiAlSiN or TiSiN bottom layer and a CrAlSiN surface layer. The composite coating has the dual functions of high-temperature corrosion resistance and diffusion resistance, in the high-temperature thermal exposure process, the surface CrAlSiN coating forms an Al2O3 and (or) Cr2O3 film with good oxidation resistance through the surface, and high-temperature corrosion protection is provided for gamma-TiAl-based alloy. And meanwhile, a Tix (Al) N + Ti5Si3 diffusion barrier layer is generated in situ on the interface of the TiAlSiN or TiSiN coating and the gamma-TiAl-based alloy at a high temperature, so that the mutual diffusion between the coating and the alloy is very slight. The composite coating provided by the invention is a hard coating, has excellent high-temperature oxidation resistance and hot corrosion resistance, and also has relatively high hardness, so that the erosion resistance and wear resistance are also relatively good.