28 results about "La element" patented technology

The invention provides a TiB2-Al-Ce-La-Fe alloy with high elongation and high thermal conductivity and a preparation method and application of the TiB2-Al-Ce-La-Fe alloy. According to the TiB2-Al-Ce-La-Fe alloy, the mass fraction of Ce is 4%-5%; the mass fraction of the Fe element is 0.3%-0.5%; the mass fraction of the element La is 1.2%-1.7%; the mass fraction of the TiB2 is 0.01%-0.1%. The preparation method of the TiB2-Al-Ce-La-Fe alloy comprises the following steps: smelting raw materials in a well type smelting resistance furnace, adding an Al-TiB2 intermediate alloy, and casting the obtained melt into a mold, so as to obtain the TiB2-Al-Ce-La-Fe alloy. The TiB2-Al-Ce-La-Fe alloy with the high elongation rate and the high thermal conductivity is good in thermal conductivity, and the thermal conductivity of the alloy ranges from 202.96 W / (m.K) to 209.27 W / (m.K); the mechanical property is excellent, and the ductility is 23.8-31%.

The application provides a copper alloy, a preparation method thereof and an elastic electronic component, and relates to the technical field of copper alloys.The copper alloy comprises the following elements in percentage by mass: the content of Ti element is 2.70-4.20%, the content of Y element is 0.010-0.030%, the content of La element is 0.010-0.030%, the content of B element is 0.010-0.020%, the total content of unavoidable impurities is less than or equal to 0.01%, and the balance is Cu element and M element; wherein, the M element is Fe element or P element, when the M element is Fe element, the content of Fe element is 0.28-0.45%, and when the M element is P element, the content of P element is 0.05-0.15%. The copper alloy has excellent tensile strength, hardness, elastic modulus and conductivity.

The invention relates to a high-conductivity semi-hard aluminum alloy material as well as a preparation method and application thereof. The high-conductivity semi-hard aluminum alloy material comprises the following alloy elements in percentage by mass: 0.02-0.04% of B, 0.20-0.30% of Zr, 0.10-0.20% of La, 0.15-0.25% of Ce, less than or equal to 0.01% of (Ti + V + Cr + Mn) and the balance of aluminum and other inevitable trace impurity elements. Through the composite addition alloying design that the B element, the Zr element, the La element and the Ce element are added into the aluminum alloy, an Al3X strengthening phase is generated under a certain preparation technology, and the electric conductivity is improved on the basis that the strength and the heat resistance are guaranteed. The preparation method of the high-conductivity semi-hard aluminum alloy monofilament comprises two stages of aging treatment, in the first stage of aging treatment, heat preservation is carried out for 0.5-1 h at the temperature of 300-325 DEG C, in the second stage of aging treatment, heat preservation is carried out for 1-2 h within the range of 200-230 DEG C, and then room temperature cooling is carried out, due to the two stages of heat treatment, the precipitation speed is increased, the evolution process of a precipitated phase is changed, and finally the aluminum alloy monofilament with good comprehensive performance is obtained.

The application relates to a high-entropy perovskite material and a preparation method and application thereof, the chemical formula of the high-entropy perovskite material is AB03, wherein the A-site element is a La element, and the B-site element is selected from 5-10 kinds of transition metal elements; the high-entropy perovskite material has a two-dimensional Turing structure, nano-particles are cross-linked and arranged, and there are gaps between the particles. Compared with the prior art, the two-dimensional Turing structure high-entropy perovskite material has unique morphology and components, excellent electrocatalytic water decomposition hydrogen production performance, and fluctuation power adaptability of clean energy such as wind energy and solar energy, and has a wide industrial application prospect.

The invention discloses an aluminum alloy and a preparation method and application thereof. The aluminum alloy comprises the following components in percentage by mass: 0.06 to 0.28 percent of Fe; 0.24% or less of Mn; less than or equal to 0.15% of Cr; zr < = 0.15%; less than or equal to 0.15% of Sc; less than or equal to 0.15% of Er; 0.24% or less of Ce; 0.24% or less of La; 0.003% to 0.04% of Ti; 0.4% to 5.6% of Mg; 0 to 0.8 percent of Si; 0 to 6.5% of Zn; 0 to 1.1% of Cu; the components of the aluminum alloy at least comprise one of Mn, Cr, Zr, Sc, Er, Ce and La. According to the aluminum alloy disclosed by the invention, the surface presents unique textures like sparkling sea, and the original mechanical property and durability of the aluminum alloy are maintained while the appearance attraction is improved.

The invention discloses an alloy diffusion source and diffusion method of a rare earth permanent magnet material, and belongs to the technical field of magnetic materials. For magnets with different Ce contents, La-containing heavy rare earth diffusion sources (LaxHRE1-x) yM100-y with different La contents are adopted, on one hand, the content of REFe2 phase in the crystal boundary of the magnet can be reduced by introducing the La element, so that the diffusion depth is increased, the crystal boundary diffusion effect is improved, on the other hand, the introduction of the La element is reduced as much as possible, and deterioration of the thin-layer crystal boundary caused by aggregation of the La element in the crystal boundary is avoided. The invention also designs a low-temperature long-time and high-temperature short-time diffusion process matched with the method, the REFe2 phase in a diffusion channel is reduced to the maximum extent, the diffusion depth of the heavy rare earth element is improved, and more and more complete high-HA core-shell structures are formed. The invention aims to solve the problem that the improvement amplitude of the coercive force of the magnet after grain boundary diffusion is small due to the fact that a REFe2 phase exists in a Ce-based magnet and hinders and absorbs a diffusion source.

The invention belongs to the technical field of inorganic functional film materials, and particularly relates to a lanthanum and manganese co-doped bismuth ferrite film and a preparation method thereof. The chemical general formula of the bismuth ferrite film is Bi (1 + Z-Y) LaYFe (1-X) MnXO3, X is the molar equivalent of Mn element, 0.09 < = X < = 0.13, Y is the molar equivalent of La element, 0.12 < = Y < = 0.18, the element Bi is added excessively, Z is the molar equivalent of Bi element, the film has N layers, Z in the first layer accounts for 8-11%, Z in the second layer to the (N-4) th layer accounts for 5-8%, Z in the (N-3) th layer to the Nth layer accounts for 3-5%, and Z in the second layer to the Nth layer accounts for 3-5%. Meanwhile, the invention provides a method for preparing the bismuth ferrite film. According to the method, parameter setting of a sol-gel process is optimized, lanthanum and manganese co-doping is achieved, the doping amount of doped ions is increased, and then the effects of reducing the leakage current of the thin film and improving the electrical performance are improved.

The invention relates to a method for determining metal elements in a lead-silver alloy through photoelectric direct-reading spectrometry, and relates to the technical field of analysis and detection. The method specifically comprises the following steps: (1) preparing a self-made analysis standard sample; (2) setting various parameters when the photoelectric direct-reading spectrometer is excited; (3) preliminarily selecting an analysis line of each metal element; (4) screening out a better analysis line; (5) selecting different regression modes and reference lines of corresponding sparks close to wavelengths to fit according to the screened better analysis lines to obtain different analysis curves, and determining the analysis lines, the reference lines and the regression modes of the corresponding metal elements according to the combination with the highest correlation coefficient, so as to establish a working curve; and (6) analyzing the metal elements in the lead-silver alloy according to the working curve. The photoelectric direct-reading spectrometry is used for determining the Ag, Ce and La elements in the lead-silver alloy, and the operation is simple, accurate, rapid and reliable.

The present invention discloses a thermoelectric material of a ternary system and a preparation method thereof, including La, Bi and Te. In terms of mass percentage, the proportion of the La element is 4-5%, the proportion of the Bi element is 10-19%, the proportion of the Te element is 2%-14%, and the rest is the O element, which is synthesized by a solvothermal method. The present invention innovatively uses La to improve the electrical properties of the material and uses Bi to reduce the thermal conductivity, ultimately improving the thermoelectric properties, ensuring that its various performance parameters do not fluctuate greatly with temperature changes, and the preparation of its material has the potential for industrial production, being suitable for miniaturized and large-scale production and manufacturing.

The invention discloses a nickel-lanthanum intermediate alloy for a high-temperature alloy. The nickel-lanthanum intermediate alloy consists of the following elements in percentage by mass: 5-32% of La, not more than 0.1% of Fe, not more than 0.1% of C, not more than 0.05% of O and the balance of Ni, the invention further discloses a preparation method of the nickel-lanthanum intermediate alloy for the high-temperature alloy, and the method comprises the following steps: step 1, putting a lanthanum block into the bottom of a crucible, uniformly laying a layer of carbon powder, loading a nickel block, vacuumizing, filling argon to reduce oxygen, and starting smelting to obtain a melt; and 2, cooling the melt to obtain a nickel-lanthanum intermediate alloy ingot, taking out the nickel-lanthanum intermediate alloy ingot, and crushing the nickel-lanthanum intermediate alloy ingot to obtain the nickel-lanthanum intermediate alloy for the high-temperature alloy. According to the nickel-lanthanum intermediate alloy, by limiting the component content, the nickel-based intermediate alloy with the La element mass fraction of 5%-32% is formed, the melting point is closer to that of high-temperature alloy matrix nickel, oxidation is not likely to happen, the high-temperature alloy smelting requirement can be met, and the nickel-lanthanum intermediate alloy is suitable for the technical field of alloy preparation.

The invention discloses a high-strength corrosion-resistant aluminum alloy for an automobile battery tray and a preparation method thereof.According to the high-strength corrosion-resistant aluminum alloy for the automobile battery tray and the preparation method thereof, by adding the La element in a specific proportion and regulating and controlling the content of Si and Mg, the corrosion resistance of the material is remarkably improved on the premise that the strength is not sacrificed, in addition, addition of the Cr element is avoided, meanwhile, the La element is introduced, the plastic deformation capacity of the alloy is effectively improved, and the service life of the alloy is prolonged. And an ultrasonic treatment process is combined to promote the uniformity of the melt, so that the complex-section profile is easier to extrude and form, the production efficiency is favorably improved, and the defects such as dragging and breaking are not easy to occur. The La element is added, the morphology of Si particles is converted from a continuous sheet shape to a discontinuous short rod shape, extension of corrosion along a grain boundary is effectively hindered, and the alloy has remarkable mechanical performance and corrosion resistance by combining the synergistic effect of a specific refining agent, components and the process.

The invention discloses a corrosion-resistant metal composite coating, a composite coating as well as a preparation method and application of the corrosion-resistant metal composite coating. The coating is prepared from La2O3 powder and Ni-based alloy containing Mo and Cr, wherein the weight ratio of the Mo element to the La element is 15: (0.5-3). The coating provided by the invention has good machinability and corrosion resistance, and especially has excellent performance in a high-temperature chlorine-containing atmosphere corrosion environment.

The invention discloses a La pre-doped high-cerium neodymium-iron-boron magnet and a preparation method thereof. According to the method, the La element with the specific content is pre-doped in the magnet base material, and the two-step grain boundary diffusion process that the continuous grain boundary network is firstly constructed and then the heavy rare earth hardened shell layer is constructed is combined, so that the problem that the grain boundary diffusion efficiency of the high-Ce magnet is low is successfully solved, the high-performance La pre-doped high-Ce neodymium-iron-boron magnet is obtained with the lowest heavy rare earth cost, and the high-performance La pre-doped high-Ce neodymium-iron-boron magnet is obtained. The La pre-doped high-Ce neodymium-iron-boron magnet has high coercive force, high residual magnetism and good temperature stability. The manufacturing process disclosed by the invention is extremely low in heavy rare earth consumption, remarkable in comprehensive cost advantage and excellent in industrial application prospect.

Disclosed are a cast 5A duplex stainless steel and a method for preparing a large casting made of this steel. By controlling contents of Cr and Mo elements and meanwhile adding W, Nb, Ce and La elements, precipitation of a brittle phase can be avoided through a coupling effect of the four elements, the precipitation of the brittle phase during a slow cooling process of the large casting is avoided, crack defects of the large casting during a casting process are fundamentally solved, and a finished product rate of the casting can be increased to 95% or above. Meanwhile, with increase of a process yield and implementation of cold mold opening and shakeout, the casting production cost is substantially reduced, safety risks during a production process are greatly reduced, and the labor intensity of workers is reduced.

The application discloses a rare earth La modified weather-resistant steel and a preparation method thereof, and belongs to the technical field of Q500qenh weather-resistant steel preparation. The weather-resistant steel comprises the following raw material components: C, Si, Mn, Cr, Ni, Cu, Mo, V, Ti, Nb, Al, 0.001-0.04wt% La, and the balance of Fe and inevitable impurities. Through precise regulation and control of the La element addition amount and the preparation process, the inherent problems of the Q500qenh steel, such as uneven as-cast grains, inclusion hazards and performance fluctuation, are solved.

The invention discloses a magnesium alloy subjected to twin crystal reinforcement and aging strengthening and a preparation method thereof. The magnesium alloy comprises the following components in percentage by weight: 4.5%-6.5% of Er element, 0.65%-1.25% of La element, 0.85%-2.25% of Sr element, 0.55%-0.75% of Zr element and the balance of metal Mg and some inevitable impurity elements. Belongs to the technical field of material alloys. The magnesium alloy has excellent room-temperature and high-temperature mechanical properties and good plasticity, after twin crystal introduction and aging treatment are conducted on the twin-crystal-reinforced aging-strengthened magnesium alloy through compression deformation, the tensile strength and the elongation of the magnesium alloy at the room temperature and the temperature of 300 DEG C are 356 MPa and 5.3% respectively, and the tensile strength and the elongation of the magnesium alloy at the temperature of 300 DEG C are 304 MPa and 8.7% respectively. The magnesium alloy has excellent tensile strength, higher high-temperature mechanical property and good plasticity, and solves the technical problems of low tensile strength, poor high-temperature mechanical property and low plasticity of the existing magnesium alloy.

The invention provides a copper alloy, a preparation method thereof and an elastic electronic component, and relates to the technical field of copper alloys. The copper alloy is prepared from the following elements in percentage by mass: 2.70 to 4.20 percent of Ti element, 0.010 to 0.030 percent of Y element, 0.010 to 0.030 percent of La element, 0.010 to 0.020 percent of B element, less than or equal to 0.01 percent of total content of inevitable impurities and the balance of Cu element and M element, wherein the M element is an Fe element or a P element, and when the M element is the Fe element, the content of the Fe element is 0.28-0.45%; and when the M element is a P element, the content of the P element is 0.05-0.15%. The copper alloy has excellent tensile strength, hardness, elasticity modulus and electric conductivity.

The invention belongs to the technical field of gas sensing, and particularly relates to a phosphorus-lanthanum co-doped TiO2-based oxygen sensing material as well as a preparation method and application thereof. According to the oxygen sensing material, TiO2 is used as a main crystalline phase, and meanwhile, phosphorus and lanthanum are introduced to form a P / La co-doped structure; wherein the doping amounts of the P element and the La element are respectively 1-3 mol% of the Ti element, and the particle size of the material is 1-3 [mu] m. Wherein the synergistic doping of P and La not only regulates and controls the lattice structure of TiO2, but also induces the generation of a large number of oxygen vacancies, and significantly increases the specific surface area and the number of gas adsorption active sites. The material can be synthesized from TiO2 powder, soluble lanthanum salt and phosphoric acid / phosphate through a solvothermal method, and is applied to a Pt interdigital electrode to obtain a high-performance oxygen sensing gas sensitive element. The problems that an existing gas sensitive element is insufficient in sensitivity, poor in selectivity and poor in environmental stability in ppb-level low-concentration oxygen detection are solved.

The application belongs to the technical field of rare earth permanent magnet materials, and particularly relates to a diffusion source, a preparation method of the diffusion source and a method for improving coercivity of a magnet. The diffusion source comprises lanthanum elements, heavy rare earth elements and non-rare earth elements; wherein the heavy rare earth elements are one or a combination of two or more of dysprosium elements, holmium elements, terbium elements and gadolinium elements; and the non-rare earth elements are one or a combination of two or more of aluminum elements, copper elements, cobalt elements and gallium elements. The diffusion source introduces La elements with stronger oxidizability, can promote Ce elements to enter a main phase, and reduce the influence of CeFe2 phase on diffusion of the heavy rare earth elements; meanwhile, due to the stronger oxidizability of the La elements than the heavy rare earth elements, the heavy rare earth oxides gathered in a grain boundary phase are reduced, the utilization rate of the heavy rare earth elements in the diffusion process is improved, the diffusion of the magnet is more uniform, the coercivity of the magnet is significantly improved, and the temperature coefficient of the magnet is improved.

The invention relates to a high-capacity easy-to-activate TiFe-based hydrogen storage alloy, which belongs to the technical field of solid hydrogen storage materials, the chemical general formula of the hydrogen storage alloy is TiFexMnyLaz, and the chemical general formula satisfies the following conditions: 0.8 < = x < = 0.96, 0.04 < = y < = 0.1, 0.005 < = z < = 0.05, and 0.84 < = x + y < = 1, the Ti-rich phase proportion in the alloy does not exceed 5%, and the La element is dissolved in the alloy. Compared with the prior art, the high-capacity TiFe-based hydrogen storage alloy provided by the invention is excellent in hydrogen storage performance and can be activated at about 80 DEG C, and the hydrogen absorption capacity at 25 DEG C can reach 1.80 wt.% or above; the TiFe-based hydrogen storage alloy provided by the invention is simple in component design, the problem that the TiFe alloy is difficult to activate can be solved only by adding a small amount of Mn and La, meanwhile, the hydrogen storage capacity of the alloy is improved, and the alloy cost is reduced.

The application belongs to the field of advanced ceramics and energy storage technology, and specifically discloses a Li-Zr double-site co-doped garnet solid electrolyte ceramic and a preparation method and application thereof. 0.1 Ga 0.1 )La3Zr 1.6 (Nb 0.2 Ta 0.2 )O 12 ; the Li element is derived from a lithium source, the Al element is derived from an aluminum source, the Ga element is derived from a gallium source, the La element is derived from a lanthanum source, the Zr element is derived from a zirconium source, the Nb element is derived from a niobium source, and the Ta element is derived from a tantalum source. The application adopts the above Li-Zr double-site co-doped garnet solid electrolyte ceramic and the preparation method and application thereof. The Li-Zr double-site co-doped garnet solid electrolyte ceramic has high ionic conductivity and can improve the cycle stability and rate performance of a solid-state battery.

The present invention discloses a magnesium-based alloy for cyclic hydrogen storage and release and a preparation method thereof. The magnesium-based alloy comprises an Mg-Ni-La alloy and a metal film. The Mg-Ni-La alloy is composed of Mg, Ni, and La elements. The content of Ni is 8.0-14.0 wt%, and the content of La is 0.1-3.0 wt%. The Mg-Ni-La alloy is a tablet formed by agglomeration of particles; the metal film coats the tablet, and the mass ratio of the metal film to the Mg-Ni-La alloy is (0.001-0.002):1. The porous metal copper film of the Mg-Ni-La alloy of the present invention has a uniform pore distribution and presents an irregular shape, which can improve the hydrogen storage and release rate, improve the hydrogen storage and release cycle performance, and reduce the hydrogen storage and release temperature and the rate of particle pulverization. It has the characteristics of low cost and simple processing technology, and is more conducive to the popularization and application of magnesium-nickel-based hydrogen storage alloys.

The invention discloses a La element reinforced rare earth magnesium alloy and a preparation method thereof, and relates to the technical field of metal material manufacturing, and the preparation method comprises the steps that La2O3 particles and an organic solvent are mixed to prepare La2O3 turbid liquid; coating the La2O3 suspension on the surface of the rare earth magnesium alloy wire, and drying to obtain the rare earth magnesium alloy wire with La2O3 particles attached on the surface; the rare earth magnesium alloy wire with the La2O3 particles attached to the surface serves as a raw material for additive manufacturing, layer-by-layer deposition is carried out through an electric arc fuse additive manufacturing process, in the deposition process, the wire is molten through an electric arc heat source to form molten drops and a molten pool, and under the high-temperature effect of an electric arc, the La2O3 particles and liquid magnesium are subjected to an in-situ reaction, so that the rare earth magnesium alloy is obtained. The decomposed La element is fused into an original rare earth magnesium alloy system; and after deposition is completed, the La element reinforced rare earth magnesium alloy deposition state component is obtained. By means of the method, the room-temperature and high-temperature mechanical properties of the rare earth magnesium alloy can be effectively enhanced, the process is simple and universal, and industrialization is easy.

A method for preparing TiB2 particle-reinforced aluminum matrix composites using lanthanum hexaboride (LaB6) and an aluminum-titanium (Al / Ti) alloy is disclosed, relating to the field of high-strength and high-toughness aluminum matrix composite preparation technology. Employing a dual-melt mixing method, the method uses lanthanum hexaboride (LaB6) and an Al / Ti alloy as the source of TiB2. During the melting process, the fine TiB2 particles generated in situ are uniformly distributed within the alloy matrix, providing dispersion reinforcement and improving the strength and toughness of the alloy material. This invention avoids introducing impurity phases such as Al3Ti found in composite fluoride salt preparation processes. The innovative introduction of La through the dual-melt mixing method refines the grain size of the aluminum alloy matrix, allowing for a more uniform and dispersed distribution of the in-situ prepared TiB2 particles within the alloy matrix, thus improving the mechanical properties of the aluminum alloy material. This method can be widely applied in fields requiring lightweight and high-toughness materials, such as new energy vehicles and aerospace.

The invention relates to the technical field of aluminum alloy materials, and discloses a cast aluminum alloy material which comprises the following components in percentage by mass: 11.5-13.5% of Si, 1.5-2.5% of Mg, 0.4-0.6% of Cu, 0.4-0.65% of Ni, 0.1-0.3% of Mn, 0.05-0.15% of rare earth elements and the balance of Al and inevitable impurities. The material cost is remarkably reduced by reducing the content of expensive Ni and Cu elements, and meanwhile, the high-temperature mechanical property of the material can be improved by adding a trace amount of La element. According to the method, the cast ingot is subjected to rapid water cooling, so that more solute atoms are dissolved in a matrix, and the mechanical property of the material can be improved by separating out a fine dispersed phase in the subsequent direct aging treatment process.

The wrought aluminum alloy for forging the steering knuckle is prepared from Al-Mg-Si alloy, and the Al-Mg-Si alloy is prepared from the following chemical components in percentage by mass: 1.05-1.45% of Si, 1.05-1.45% of Al, 1.05-1.45% of Si, 1.05-1.45% of Al, 1.05 0.75% to 1.20% of Mg; 0.6 to 0.9 percent of Mn; 0.2 to 0.4 percent of Fe; 0.2 to 0.3 percent of Cr; 0.1% to 0.3% of La; 0 to 0.1 percent of Cu; and 0.01 to 0.06 percent of Ti. The invention has the following beneficial effects: by increasing the contents of Mn and Cr elements, the corrosion resistance and impact resistance are enhanced; as a rare earth additive with relatively low cost, the La element is suitable for being added and used in civil industry; the La element can form an AlSiLa second phase to promote the dispersion strengthening effect of particles; la is used for modifying a long-strip-shaped beta-AlFeSiLa phase into short-rod-shaped alpha-AlFeSi, so that the harm caused by the Fe element is reduced; and the La element is enriched on the surface of the Mg2Si strengthening phase, so that the corrosion resistance of the Al-Mg-Si element is improved.

The present invention belongs to the technical field of tungsten alloy detection, specifically, a method for determining the La element content in a tungsten alloy, and adopts an inductively coupled plasma atomic emission spectrometer to determine the lanthanum element, which has the advantages of high precision, simple operation, less interference, low detection limit, etc. The present invention can avoid the pollution caused by sample pretreatment by subjecting the sample to be tested to high temperature oxidation, dissolving the oxidized sample with hydrogen peroxide, precipitating lanthanum with magnesium as a carrier in an alkaline medium of triethanolamine solution, filtering and separating to effectively remove the tungsten matrix, dissolving the precipitate with nitric acid and perchloric acid, and directly exciting with an argon plasma light source in a dilute nitric acid medium, thereby achieving the purpose of eliminating background and spectral line interference, improving accuracy, and being able to well meet the determination requirements of the rare earth element La in tungsten alloy.

The application discloses a kind of rare earth enhanced electromigration resistance SnAgCu solder and its preparation method and application, belong to electronic packaging solder field.The application solves the problem of insufficient anti-electromigration capacity of existing SnAgCu alloy solder etc.The application adds rare earth element Ce, La in Sn3.5Ag0.75Cu alloy solder, and controls its content in alloy, utilizes the higher affinity of rare earth element Ce, La element and Sn element, after welding, in alloy solder organization, it tends to form Ce-La-Sn regular polygon second phase by Ce, La, Sn, which is jointly composed, the second phase particle effectively refines the organizational structure of alloy solder, and effectively resists the movement of dislocation line when alloy solder produces plastic deformation, so that Sn3.5Ag0.75Cu alloy solder strength and anti-electromigration performance are improved.