82 results about "Spinel" patented technology

Container whose inner wall surfaces are at least partially covered with a coating having the following crystallized phases, as a percentage based on the total mass of the crystallized phases: Spinel MgAl2O4: 10% to 60%, and Crystallized phases other than spinel MgAl2O4 and corundum: < 10% Corundum: complement to 100%.

This invention provides a composite magnesium-iron modified biochar and its method for purifying industrial wastewater, belonging to the technical field of functional materials for water treatment. The composite biochar of this invention uses porous biochar as a substrate, and through bimetallic impregnation, in-situ co-precipitation nucleation with pH control, and programmed temperature calcination, a composite crystalline phase of magnesium-iron layered bimetallic oxide and magnesium-iron spinel is anchored in-situ on its surface and internal pores. This material exhibits excellent magnetic field response characteristics and abundant bimetallic active sites. When added to composite wastewater, the bimetallic synergistic mechanism enables one-step simultaneous adsorption and degradation of COD, ammonia nitrogen, and total phosphorus; after the reaction, only an external magnetic field is needed to quickly achieve solid-liquid separation. This invention completely solves the problem of powder material recovery, and is resistant to desorption and regeneration, exhibiting excellent long-term recycling performance.

This invention discloses a cubic spinel-structured sulfide composite gas-sensitive material, a gas sensor, its preparation method, and its application, belonging to the field of gas sensor technology. The preparation method of this composite gas-sensitive material involves using FeCl2, CdCl2, and InCl3 as metal sources, and thiourea as a sulfur source, placing them together in a solvent of water, adding citric acid or sodium citrate as a dispersant, and obtaining a precursor material through a hydrothermal reaction. After calcination and annealing, a cubic spinel-structured FeIn2S4 / CdIn2S4 heterojunction material powder is obtained. The two gold electrodes and the ceramic tube of the gas sensor are coated with the cubic spinel-structured sulfide composite gas-sensitive material. The gas sensor based on this invention, made from a cubic spinel-structured sulfide composite gas-sensitive material, has a simple manufacturing process, low production cost, and is suitable for industrial mass production. It has broad application prospects in the field of acetone detection in trace hazardous situations.

The invention discloses a method for preparing compact fine-grain magnesium aluminate spinel ceramic by low-temperature sintering, which comprises the following steps: S1, mixing ethanolamine, magnesium acetate tetrahydrate and water according to a certain proportion to obtain a mixed solution A; s2, mixing citric acid, aluminum isopropoxide and water according to a certain proportion to obtain a mixed solution B; s3, slowly adding the mixed solution A into the solution B in the step S2 to form uniform colloid; s4, drying the colloidal solution to obtain a dried precursor; s5, performing low-temperature calcination on the precursor to obtain nano magnesium aluminate spinel powder; s6, carrying out ball milling and spray granulation to obtain spherical granulation powder with uniform particle size; s7, performing dry pressing molding and cold isostatic pressing molding to obtain a to-be-sintered ceramic biscuit; and S8, sintering in a muffle furnace to obtain the final magnesium aluminate spinel ceramic. The powder is subjected to ball milling, spray granulation, dry pressing forming and cold isostatic pressing forming, and then the compact fine-grain magnesium aluminate spinel ceramic is prepared through low-temperature sintering.

The invention relates to the technical field of ethylbenzene dehydrogenation, in particular to a preparation method and application of a spinel CoFe2O4 oxygen carrier, and the preparation method comprises the following steps: dissolving cobalt salt and iron salt in water according to a specific molar ratio, adding ethylene glycol, methanol and a polymethyl methacrylate template agent, uniformly mixing, drying, carrying out programmed temperature rise calcination in an oxygen-containing atmosphere, and calcining to obtain the spinel CoFe2O4 oxygen carrier. The CoFe2O4 oxygen carrier with a single spinel crystal structure is obtained. The oxygen carrier is used as a recyclable lattice oxygen source and can catalyze ethylbenzene oxidative dehydrogenation to generate styrene at the ultralow temperature of 200-400 DEG C, especially about 250 DEG C, both the ethylbenzene conversion rate and the styrene selectivity can reach 96% or above, and the performance degradation rate is smaller than 5% after at least 41 times of redox cycles. The process conditions are mild, the oxygen carrier structure is stable, the activity is high, and a new way is provided for energy-saving and low-carbon production of styrene.

A composite particle composed of spinel and disordered rock salt domains interspersed therein, made by removing lithium from a disordered rock salt to form a lithium deficient disordered rock salt and heating the lithium deficient disordered rock salt for a time and temperature to form the composite particle.

The invention relates to a spinel-perovskite three-phase high-entropy ceramic powder material, the chemical formula of the three-phase high-entropy ceramic powder material is (A1xA2yA3zA4uA5v) Mn2O4, A1, A2, A3, A4 and A5 are four transition metal elements of Ca, Cu, Ni, Co, Zn and Mg and one rare earth element of La and Pr, the molar ratio of metal atoms is x: y: z: u: v: 2, and x + y + z + u + v = 1; the perovskite-spinel composite material has a spinel phase and a perovskite phase of two cubic structures. The high-entropy ceramic powder material has three phases coexisting, has excellent broadband emissivity and high-temperature thermal stability, and can be used as an infrared radiation material to be widely applied to high-temperature infrared radiation environments, such as the fields of aerospace thermal protection, industrial high-temperature kilns, power station boiler thermal management systems and the like.

A method of preparing a calcined hydrogenolysis / hydrogenation catalyst includes mixing a copper-containing material, manganese-containing material, sodium aluminate, and water to obtain an aqueous slurry; contacting the aqueous slurry with a caustic material to form a precipitate in a caustic aqueous slurry; removing the precipitate from the caustic aqueous slurry; and removing residual water from the precipitate to form a dried precipitate; calcining the dried precipitate to form the calcined hydrogenolysis / hydrogenation catalyst exhibiting a Brunauer-Emmett-Teller (“BET”) surface area of about 5 m2 / g to about 75 m2 / g. The calcined hydrogenolysis / hydrogenation catalyst may include a spinel structure crystallite size of about 15 nm or less. The calcined hydrogenolysis / hydrogenation catalyst may include a tenorite crystallite size of about 20 nm to 30 nm.

This invention belongs to the field of enamel material preparation technology, specifically relating to a corrosion-resistant enamel material and its preparation method. The corrosion-resistant enamel material of this invention comprises a Q345R low-alloy steel substrate and an enamel coating; wherein the enamel coating consists of a base glaze layer and a top glaze layer. The base glaze layer is composed of glaze A, silica, and quartz powder; the top glaze layer is composed of glaze B, modified nano-sepiolite, and magnesium aluminum spinel micro powder. The corrosion-resistant enamel material of this invention uses a Q345R low-alloy steel substrate as the base material and a composite coating consisting of a base glaze and a top glaze as the enamel coating. The base glaze layer is tightly adhered to the surface of the Q345R low-alloy steel substrate, achieving a tight bond between the enamel coating and the substrate, and serving as an interlayer transition. The top glaze layer covers the base glaze layer and mainly serves a corrosion-resistant function. Through the synergistic function of the base glaze and the top glaze, corrosion protection of the substrate is achieved.

Provided are: a carbon dioxide reduction catalyst that can reduce carbon dioxide under mild conditions; a carbon dioxide reduction method using the carbon dioxide reduction catalyst; and a carbon dioxide reduction apparatus. The metal oxide according to the present invention has a spinel-type crystal structure comprising a metal element A, manganese and oxygen. The A comprises at least one metal element selected from the group consisting of nickel and copper, the (manganese) / (oxygen) molar compositional ratio is 1:1.8 to 1:2.2, and the (metal element A) / (manganese) molar compositional ratio is 1:1.7 to 1:2.3. The metal oxide is characterized in that the ratio of the intensity of a peak having a 2θ value of 16° to 20° (P18°) to the intensity of a peak having a 2θ value of 35° to 39° (P37°) in an X-ray diffraction pattern obtained by an X-ray diffraction measurement using Cu-Kα line, i.e., I18° / I37°, is 0.2 or more.

The invention discloses an acanthosphere-shaped multi-interface type metal oxide magnetic particle and a preparation method and application thereof.The magnetic particle comprises a core composed of magnetic nanoparticles and a shell layer composed of titanium oxide nanosheet spines arranged in a radial mode, and the magnetic particle has superparamagnetism, high specific surface area and rich active sites; and a large number of trap spaces matched with the exosome scale range, so that the method can be used for efficiently enriching and separating the exosome from the biological fluid. Meanwhile, the magnetic core has an out-phase junction composed of amorphous phase titanium oxide and anatase phase titanium oxide, a heterojunction interface composed of titanium oxide and the magnetic core and an ordered spine microstructure, the synergistic effect of the multi-interface effect and the point effect is fully exerted under laser irradiation, the excellent ultraviolet absorption capacity and electron-hole separation efficiency are shown, and the magnetic core has the good application prospect. The method is used for laser desorption ionization mass spectrometry, efficient in-situ pyrolysis of the exosome is achieved, desorption and ionization of metabolite in a lysis solution are promoted, and a high-resolution mass spectrum of the metabolite of the exosome is obtained.

The invention discloses a preparation method of a temperature-sensitive color-changing iron oxide-based material, and belongs to the technical field of iron oxide pigments. The preparation method comprises the following steps: mixing iron oxide powder and cobalt aluminate spinel powder, carrying out ball milling, and carrying out spray drying granulation on the mixed powder to obtain composite particles; adding the composite particles into a zirconium oxide solution for hydrothermal reaction, filtering and washing after the reaction is finished, and calcining at high temperature to obtain the temperature-sensitive color-changing iron oxide-based material. The ZrO2 buffer layer is introduced, the problem that an existing composite system is insufficient in cycling stability is effectively solved, after multiple times of temperature cycling, the color changing efficiency of the pigment can still be maintained at a high level, and the application reliability of a product needing a temperature-sensitive color changing function to be repeatedly used for a long time is ensured.

The application discloses a formaldehyde catalytic oxidation agent and a preparation method and application thereof, and aims at solving the technical problem of how to use copper manganese oxide with a spinel structure as an active component to efficiently and stably catalyze and oxidize formaldehyde at room temperature. The formaldehyde catalytic oxidation agent comprises the following components in percentage by mass: 70-94% of an activated carbon carrier with oxygen vacancy defects on the surface; 5-20% of an active component composed of copper manganese oxide with a spinel crystal phase structure; and 1-10% of an anti-poisoning auxiliary agent composed of an alkaline alkali metal salt; wherein, the active component and the anti-poisoning auxiliary agent are jointly loaded on the activated carbon carrier. The formaldehyde can be efficiently mineralized and decomposed at room temperature, and the service life is long.

The invention discloses a special chemical additive for LDS (laser direct structuring) with high light resistance and weather resistance and a preparation method of the special chemical additive, and belongs to the technical field of laser direct structuring materials. The additive is prepared from inorganic powder through surface pretreatment and composite ionomer coating, the inorganic powder is composed of copper-chromium oxide spinel and magnesium-aluminum-based hydrotalcite according to the mass ratio of (3-5): 1; the surface pretreatment agent is phytic acid; the composite ionomer coating layer comprises an ethylene-aluminum maleate ionomer and at least one auxiliary ionomer selected from a short-side-chain perfluorosulfonic acid ionomer and a zinc type vinyl acid ionomer. The preparation method comprises the steps of premixing, phytic acid surface treatment, composite ionomer coating, vacuum drying and the like. According to the invention, phytic acid treatment and composite ionomer synergistic coating are carried out, and nanosheets can be selectively introduced, so that the light resistance and weather resistance of the additive are remarkably improved, and the problem that the existing LDS material is easy to yellow and age is solved.

The invention discloses a multi-stage synergistic self-repairing type composite enhanced converter slag-stopping sliding plate brick and a preparation method thereof. The material is composed of zirconium system / corundum / spinel multi-scale aggregate, a boron system self-repairing reinforcement phase containing ZrB2, B4C and Al3BC3, a metal Si / Al in-situ hard phase generating agent and functional powder, and is prepared by adopting a normal-pressure sectional drying and high-temperature sintering process. In the service process, cracks are blocked through ZrO2 / B2O3 glass phases, the oxidation resistance, the wear resistance and the thermal shock resistance are improved through Al18B4O33 whisker bridging and SiC / Al4C3 and other in-situ hard phases, the service life of the sliding plate is remarkably prolonged (larger than or equal to 20 heat times), meanwhile, the low-heat-conductivity and low-energy-consumption processes are achieved, and the sliding plate is suitable for the fields of converter slag control and other high-temperature fire-resistant components.

Provided is a secondary battery in which charge / discharge characteristics can be improved. The secondary battery comprises: a positive electrode that includes positive electrode active material particles; a negative electrode; and an electrolyte that contains an aqueous solvent. The positive electrode active material particles include a lithium manganese composite oxide having a spinel crystal structure. The pH of the electrolyte is smaller than 9. The ratio I2 / I1 of the maximum value I1 of scattered light intensity in the range of 600 cm-1 to 700 cm-1 and the maximum value I2 of scattered light intensity in the range of 950 cm-1 to 1000 cm-1 as measured by Raman spectroscopy using excitation light of 532 nm on the surface of the positive electrode active material particles is 0.2 to 2, inclusive. The molar ratio of phosphorus to manganese as measured by X-ray photoelectron spectroscopy on the surface of the positive electrode active material particles is 0.2 to 5, inclusive.

The invention relates to a magnesium hydroxide composite flame retardant and a preparation method and application thereof, and belongs to the technical field of flame retardant materials.Porous graphite phase carbon nitride powder is prepared through secondary calcination, FeNi2S4 is generated on the surface of the powder in situ to form heterojunctions, then nano magnesium hydroxide is loaded, silicon dioxide is coated, the flame retardant efficiency and the smoke suppression effect are remarkably improved, and the flame retardant efficiency and the smoke suppression effect are improved; ammonia gas and carbon dioxide gas released during synergistic calcination of melamine and ammonium bicarbonate form porous channels in graphite phase carbon nitride powder, sufficient anchoring sites are provided for FeNi2S4 and magnesium hydroxide, transition metal sites of iron ions and nickel ions can catalyze a base material to form carbon in a trans-spinel structure of FeNi2S4, and the transition metal sites of the iron ions and the nickel ions can catalyze the base material to form carbon in the trans-spinel structure of FeNi2S4. Graphite-phase carbon nitride promotes graphitization of a carbon layer, the carbon yield is increased through synergism of graphite-phase carbon nitride and graphite-phase carbon nitride, release of combustible gas is effectively blocked, magnesium hydroxide is uniformly loaded in a nano-particle form, and crystal water is released through high-temperature decomposition to absorb latent heat.

The invention discloses high-strength impact-resistant tempered glass and a preparation method thereof, and belongs to the technical field of inorganic non-metallic materials. A rare earth doped Al2O3-ZrO2 nano-composite precipitated phase is uniformly dispersed and distributed in a tempered glass matrix, and the rare earth doped Al2O3-ZrO2 nano-composite precipitated phase is composed of Y3 + or Ce4 + stabilized tetragonal phase ZrO2 and spinel type Al2ZrO5; the glass has a gradient stress structure, and comprises an upper surface compressive stress layer, a lower surface compressive stress layer and a subsurface toughness buffer area positioned below the upper surface compressive stress layer and the lower surface compressive stress layer, and the buffer area is in a micro-tensile stress state and contains the nano-composite precipitated phase. Through the collaborative design of rare earth doped nano phase change toughening and asymmetric gradient stress, the mechanical property of hard surface and tough interior is achieved, the impact resistance height is high, the fracture toughness is large, the structural integrity is still kept after multi-point impact, and the composite material is particularly suitable for high-safety-requirement scenes such as building curtain walls, explosion-proof windows and new energy automobile skyscreens.

The application discloses a method for synthesizing spinel nanomaterials based on subcritical technology, and the specific preparation method is as follows: precursor solution and additives are put into a high-pressure reaction kettle for mixing, then the characteristics of high diffusion coefficient, high reaction rate and low surface tension of subcritical water are utilized, a heating device (160-180 DEG C) and different reaction atmospheres (oxygen, helium or nitrogen) are used to promote the uniform mixing and high-efficiency reaction between reactants, and the reaction is kept for 30-180 min, so that the crystal nucleates rapidly and forms nanoparticles. Compared with traditional synthesis methods of spinel nanomaterials, the method has good safety, stability and controllability, and is a subcritical technology method for synthesizing spinel nanomaterials with wide prospect.

A composition comprising a disordered rock salt having a cation comprised of lithium and at least one other metal and an anion comprised of oxygen having a coating comprised of a metal fluoride, a metal oxyfluoride or combination thereof may be made by a dry or wet method. The methods comprise intermixing a metal fluoride and a disordered rock salt and heating to a temperature to react a metal fluoride with the DRS. The method may form a spinel in addition to the metal fluoride or metal oxyfluoride, when in the presence of a base such as ammonium.

The invention discloses a method for preparing a MgAlO4-Ca2Mg2Al28O46 composite material by an electric melting method. The MgAlO4-Ca2Mg2Al28O46 composite material is prepared from the following raw materials in percentage by mass: 70-90% of industrial aluminum oxide, 2-15% of magnesium oxide and 2-15% of quick lime. A small amount of CaO and MgO are introduced into Al2O3, a composite refractory material of Ca2Mg2Al28O46 (C2M2A14), magnesium aluminate spinel (MA) and a small amount of calcium hexaluminate (CA6) is obtained after smelting, the grain size of the composite refractory material reaches the millimeter level, and the composite refractory material is large in grain size, high in direct bonding degree among grains, few in grain boundary, high in thermodynamic and chemical stability and good in steel slag corrosion resistance.

The application discloses a spinel lithium manganate electrode material with selective crystal face passivation and a preparation method thereof. The electrode material comprises a spinel lithium manganate matrix and a disordered rock salt structure passivation layer selectively constructed on high-activity crystal faces such as {110} and {100} of the matrix; and the stoichiometric general formula of the matrix is Li x Mn 2‑y M y O4 (M is a doping element, 0.85<=x<=1.15, 0<=y<=0.25). The preparation method comprises the following steps: adding the matrix into specific acid liquid to obtain a crystal face selective acidization matrix, and then performing heat treatment to obtain the spinel lithium manganate electrode material with selective crystal face passivation. The application can effectively inhibit manganese dissolution, enhance the high-temperature surface structure stability of the material, and does not significantly affect the electrochemical capacity, and the process is simple, does not need complex equipment, and is easy for industrialized production.

A lithium-free transparent spinel glass ceramic and preparation method therefor and use thereof. The lithium-free transparent spinel glass ceramic is prepared from a base glass by heat treatment, and a spinel crystal is the main crystalline phase. The composition of the glass ceramic comprises the following oxides in mol%: SiO2 38.00 to 48.00 mol%, Al2O3 25.50 to 30.00 mol%, ZrO2 3.00 to 5.00 mol%, MgO 5.00 to 8.00 mol%, ZnO 8.00 to 14.00 mol%, Na2O 7.20 to 14.00 mol%, B2O3 3.00 to 8.00 mol%, K2O 0 to 2.00 mol% and Y2O3 0 to 1.00 mol%, and is substantially free of Li2O. The lithium-free transparent spinel glass ceramic does not use high-cost lithium, and can achieve excellent surface stress characteristics and deep-layer stress characteristics through chemical strengthening, thereby obtaining an excellent drop resistance performance.

This invention provides a transparent spinel microcrystalline glass with spinel as the main crystalline phase and excellent optical properties. Compared with existing spinel microcrystalline glasses, the spinel microcrystalline glass provided by this invention is easier to polish, has lower polishing difficulty, and higher polishing efficiency. By adjusting the glass formulation and utilizing the synergistic effect of specific amounts of various oxide components, this invention achieves the desired target crystalline phase while giving the microcrystalline glass a specific microstructure. This not only ensures the high intrinsic strength and excellent optical properties of the microcrystalline glass but also significantly reduces the polishing difficulty of the spinel microcrystalline glass while ensuring that its weather resistance meets the application requirements. This results in higher polishing efficiency and easier mass production.

The present application provides a positive electrode plate and the use thereof. The positive electrode plate comprises a positive electrode current collector and a positive electrode active material; the positive electrode active material comprises spinel-type lithium manganate and a ternary material; the crystal X-ray diffraction pattern of the positive electrode plate contains a first characteristic peak having a 2θ of 18.7±0.5°, a second characteristic peak having a 2θ of 44.1±0.2°, a third characteristic peak having a 2θ of 44.6±0.2°, and a fourth characteristic peak having a 2θ of 64.3±0.5°, the intensity of the first characteristic peak being I1, the intensity of the second characteristic peak being I2, the intensity of the third characteristic peak being I3, and the intensity of the fourth characteristic peak being I4, wherein I1 / (I2+I3) is ≥ 2 and I2 / I4 is ≥ 2.

The application provides a nanocrystalline magnetic hydroxyl ferric oxide material and a preparation method and application thereof, and belongs to the field of material preparation. A platinum net is used as a cathode, a carbon rod is used as a counter electrode, Ag / AgCl is used as a reference electrode, and FeCl3 aqueous solution is used as an electrolyte. After voltage is applied by a constant voltage discharge device for electrolysis, flocculent substances can be obtained, and hydrogen gas is generated. Then, the precipitated substances are collected after washing and suction filtration, and the precipitated substances are dried and ground to obtain a hydroxyl ferric oxide material with a spinel crystal structure. The hydroxyl ferric oxide material is a nanoparticle with a particle size of 5-100 nm, has magnetism, and the saturation magnetization value can reach 47.8emu / g. The hydroxyl ferric oxide material is used as a negative electrode material and is applied to a lithium ion button cell. The synthesis method is novel, the preparation process is simple, the reaction condition is mild, the operation is safe, the energy consumption in the reaction process is low, and the method is easy to scale up. The synthesized hydroxyl ferric oxide has the characteristics of high product quality, few impurities and good dispersity.

The application discloses a medium volume density heat-insulating refractory material based on CA6, a preparation method of the medium volume density heat-insulating refractory material and application of the medium volume density heat-insulating refractory material. The medium volume density heat-insulating refractory material based on CA6 has a phase including CA6 and one or more than two phases selected from C2M2A14, CM2A8, magnesium-aluminum spinel and corundum. The heat-insulating refractory material has high purity, good high-temperature stability, uniform tissue structure, stable performance, low thermal conductivity and good corrosion resistance to metal melt and molten slag.

The invention belongs to the technical field of dry granular glaze manufacturing, and particularly relates to a dry granular glaze with strong stereoscopic impression, a ceramic large plate and a preparation method of the dry granular glaze. The dry granular glaze with strong stereoscopic impression belongs to calcium-zinc glaze, and by improving the components of the dry granular glaze, high-content zinc oxide can partially replace calcium ions and magnesium ions, so that the dry granular glaze with strong stereoscopic impression is prepared. According to the present invention, the surface of the ceramic large plate is subjected to a reaction with the silicon dioxide to form the stable network, such that the wear resistance of the surface of the ceramic large plate is improved, the crystallization effect can be retarded, and the precipitation of the zinc-aluminum spinel and other microcrystals can be promoted so as to improve the texture level of the bright face brick, such that the tone is clearer, and the transparency is good; according to the present invention, the fine texture and the crystal texture of the natural stone material can be well restored, the pattern has characteristics of strong three-dimensional effect, good permeability, excellent antifouling property, simple preparation process, and suitableness for the preparation of the large-size ceramic plate.

To provide a positive electrode material including a spinel-type lithium manganese oxide having excellent charge / discharge characteristics and output characteristics at high temperatures, and a lithium secondary battery having excellent charge / discharge characteristics and output characteristics at high temperatures.SOLUTION: A positive electrode material includes a spinel-type lithium manganese oxide having a surface on which a phosphate and at least one metal element selected from aluminum, magnesium, zinc, nickel, cobalt, iron and calcium are contained and which is represented by the chemical formula Li1+XMn2-X-YMgYO4 (X and Y satisfy 0.02≤X≤0.10 and 0.05≤Y≤0.30, respectively), and which has a phosphorus / manganese molar ratio of 0.001 or more and 0.1 or less, and there is also provided a usage thereof.SELECTED DRAWING: None

The application relates to a spinel-perovskite three-phase high-entropy ceramic powder material, which has a chemical formula of (A 1x A 2y A 3z A 4u A 5v )Mn2O4, wherein A1, A2, A3, A4 and A5 are four transition metal elements in Ca, Cu, Ni, Co, Zn and Mg and one rare earth element in La and Pr, the molar ratio of metal atoms is x:y:z:u:v:2, and x+y+z+u+v=1; the high-entropy ceramic powder material has two cubic crystal system spinel phases and a perovskite phase. The three phases of the high-entropy ceramic powder material coexist, have excellent wide-band emissivity and high-temperature thermal stability, and can be widely used as an infrared radiation material in high-temperature infrared radiation environments, such as aerospace thermal protection, industrial high-temperature kiln, power station boiler thermal management systems and the like.