340results about How to "The preparation method is simple and reliable" patented technology

The invention relates to a piezoelectric twin-wafer type MEMS energy collector and a preparation method thereof, which belong to the technical field of micro electromechanics. The piezoelectric twin-wafer type MEMS energy collector comprises a plurality of piezoelectric twin-wafer cantilever beams, wherein each piezoelectric twin-wafer cantilever beam comprises a silicon immobilizing base, a piezoelectric twin wafer and mass blocks, wherein the piezoelectric twin wafer comprises a metal base chip, a two-layer piezoelectric thin film and a two-layer electrode. The method comprises the following steps: using a pulling method for attaching the piezoelectric film to the upper surface and the lower surface of the metal base chip; sputtering or evaporating a layer of metal materials on the piezoelectric film to obtain the piezoelectric twin wafer; pasting the piezoelectric twin wafer on the upper surface of the silicon chip; forming a rectangular groove on the lower surface of the silicon chip; cutting the silicon chip and the piezoelectric twin wafer; preparing a plurality of mass blocks; pasting the mass blocks on the suspended end of the piezoelectric twin wafer; and polarizing the piezoelectric twin wafer. The invention has high conversation efficiency, high output power and simple and reliable manufacture, and has wide application prospects in the design and the manufacture of wireless sensor network nodes.

The invention relates to a CrMoNbTiZr high-entropy alloy material and a preparation method of the CrMoNbTiZr high-entropy alloy material. The high-entropy alloy material comprises Cr, Mo, Nb, Ti and Zr, wherein the molar ratio of Cr to Mo to Nb to Ti to Zr is 1:1:1:1:1. The preparation method comprises the steps that 1, powder is prepared, and particularly metal powder is prepared according to the equal molar ratio; 2, powder mixing is carried out, and particularly the prepared powder is mixed to be uniform in a V-shaped powder mixing machine; 3, pressing and block forming are carried out, and particularly the mixed powder is subjected to cold pressing under a pressing machine to form blocks; and alloy is molten, and particularly a vacuum non-consumable arc melting furnace is used for melting the samples which are obtained after the powder is pressed to be blocks. The CrMoNbTiZr high-entropy alloy material mainly comprises a BCC solid solution phase and a small amount of Laves phase, meanwhile has the advantages of being high in hardness, high in corrosion resistance and the like, and has the good application prospect in the field of wear resistance and corrosion resistance.

The invention relates to a preparation method for bionic nano-silver. Silver nitrate and natural polymer or derivative of the natural polymer are raw materials and react in a water solution under stimulation of sunlight or visible light. The natural polymer is protective agents, reducing agents and photosensitizer and generates the nano-silver under stimulation of sunlight or low-frequency visible light at the room temperature. The prepared nano-silver has high safety under the protection of the natural polymer, can be applied to biomedical materials or daily chemical products, gives play to an antibacterial function, and can obviously reinforce the Raman signals of molecules to be detected when used as Raman base materials. The preparation method for the bionic nano-silver is simple, reliable, capable of meeting the requirements for the shape and performance of the nano-silver in the field of biomedicine or spectrums, good in biosecurity, capable of controlling the shape and the particle size of products, and wide in application range.

The invention discloses a solar cell module and a preparation method thereof. The solar cell module is composed of five layers of structures. A first layer of conducting backing plate, a second layer of conducting resin connecting points, a third layer of back contact battery piece, a fourth layer of packaging materials and a fifth layer of tempered glass are sequentially stacked together; the first layer of conducting backing plate is of a novel stacked structure. With the design, the solar cell module without welding strips and the preparation method thereof are low in cost and easy to realize.

The invention provides a method for preparing a straw fiber composite material. The method comprises the following steps: (1) pretreating straw fibers; (2) mixing the straw fibers; (3) performing hot press molding; and (4) packaging the product. The preparation method disclosed by the invention has the advantages that the method is simple, reliable and easy to implement, and the prepared composite material is reproducible and degradable and becomes an environment-friendly and energy-saving ideal material; the material can be recycled, and an industry chain of circular economy can be formed; and the composite material is good in mechanical property, excellent in performance, low in cost and wide in application and can be applied to the fields of industries such as buildings, home furnishing and automobiles.

The invention relates to a charcoal-supported transition metal carbon-nitrogen compound, a preparation method and application thereof. The transition metal compound is supported on a charcoal carrier by adopting a dipping method, and is dried and roasted to obtain a precursor. The prepared precursor is subjected to temperature programmed reaction in mixed gas of ammonia gas and hydrogen gas to obtain the transition metal carbon-nitrogen compound highly dispersed on the charcoal carrier. The charcoal-supported transition metal carbon-nitrogen compound prepared through the method shows good catalytic activity in various hydrogen-involved reactions.

The invention belongs to the technical field of aquatic feeds, relating to a special feed for living through the winter for tilapia. The special feed for living through the winter for the tilapia consists of raw materials and addictives. The invention is characterized in that the raw materials comprise the following components in parts by weight: 35 parts of rice bran, 35 parts of bean pulp, 13 parts of fish meal, 14 parts of wheat middling, 1.5 parts of meat and bone meal, 0.5 part of salt and 1.0 part of vegetable oil; the addictives are vitamin C and vitamin E, the content of the vitamin C is 800-1000ppm of the raw material by weight, and the content of the vitamin E is 100-200ppm of the raw material by weight; and the rice bran, the bean pulp, the fish meal, the wheat middling, the meat and bone meal and the salt are smashed, then fully mixed with the vegetable oil and granulated, drying and cooling are carried out, the vitamin C is prepared into a water solution with the concentration of 80-100g / l, the vitamin E is prepared into a vegetable oil solution with the concentration of 10-20g / l, the water solution with the concentration of 80-100g / l and the vegetable oil solution with the concentration of 10-20g / l are sprayed on the granulated mixture, and finally, sealed package is conducted after drying. The feed has high crude protein and crude fat contents and the added vitamins C and E, and has obvious effect with above 90% of overwintering survival rate in cultivating oreochromis aureus, gift tilapia and nile tilapia.

The invention discloses a vanadium manganese sodium phosphate @ 3D porous graphene composite material, a preparation method thereof, and applications of the vanadium manganese sodium phosphate @ 3D porous graphene composite material in sodium-ion batteries. The vanadium manganese sodium phosphate @ 3D porous graphene composite material is formed via in-suit growth of flaky vanadium manganese sodium phosphate on a 3D porous graphene skeleton. The preparation method comprises following steps: oxidized graphene is added into an aqueous solution containing a phosphorus source, a sodium source, a manganese source, and a vanadium source; ultrasonic dispersion is adopted, stirring reaction is carried out at room temperature, an obtained product is delivered into a reaction kettle for hydro-thermal reaction so as to obtain a hydrogel precursor; the hydrogel precursor is subjected to freeze drying so as to obtain an aerogel; and the aerogel is subjected to calcining so as to obtain a finished product. The vanadium manganese sodium phosphate @ 3D porous graphene composite material possesses excellent electrochemical performance as a sodium-ion battery cathode material. Operation of the preparation method is simple; cost is low; and commercial application prospect is promising.

The invention relates to composite puffed oat whole powder and a preparation method thereof. The whole powder comprises the following compositions in portion by weight: 25 to 40 portions of oat, 45 to 65 portions of maize, and 10 to 15 portions of dioscorea opposita thumb. The composite puffed oat whole powder is in light yellow powdered shape, has aromatic flavor and puffing rate (determined by a volume method) reaching 150 to 170 percent. The whole powder becomes into paste through pouring by boiling water to be directly eaten, has smooth mouthfeel, good water solubility, rehydration rate reaching 6 to 8 and pure and aromatic flavor, not only maintains nutrient health-care components and unique flavor of oat whole powder and the dioscorea opposita thumb, but also leads the maize to achieve the aim of making coarse grains into fine foods, accords with the requirement on health of consumers and social fashion, and has good social benefit and economical benefit.

The invention relates to the field of medical appliances, and provides a medical sacculus and a preparation method thereof. The medical sacculus comprises a main body and a drug coating which is arranged on the main body and is used for treating hemadostenosis. The medical sacculus is characterized in that the main body comprises an inner layer which is made of a non-water-soluble polymer material, and an outer layer which is made of a non-water-soluble polymer material and is provided with a porous structure, wherein the pore size of the main body is submicron or micron, and the drug coating is coated on the outer surface of the outer layer and a hole in the porous structure of the outer layer. The invention further provides a method of preparing the medical sacculus. According to the medical sacculus, drugs are guaranteed to be firmly stuck and loaded on the outer layer of the main body, the initial drug capacity is increased, and the drug loss in a sacculus delivery process is reduced, so that after the medical sacculus reaches a diseased region, the sufficient drug quantity is released to a vascular wall, and furthermore, the preparation method of the medical sacculus is simple, reliable and lower in cost, and is beneficial for mass production.

The invention provides a slurry of waterborne polyurethane for synthetic leather produced by the replacing wet method, and provides a preparation method for the slurry. The slurry has low cost, good effect, safety, environmental protection, no toxic and side effects. The invention also provides the preparation method for using the slurry of water-borne polyurethane to produce synthetic leather by the replace the wet method and a prepared synthetic leather bass product. The preparation method for producing synthetic leather by the replace the wet method is simple and reliable, has no hazardous and noxious gas emission in the manufacturing process, and can realize clean production and safety production. The synthetic leather base prepared by the waterborne polyurethane has high property of simulating the derma and good ventilation property, has no toxic and residue odor, fully corresponds to relevant national standards, and has low cost and strong market competitiveness.

The invention relates to an expansive char-forming flame-retardant polypropylene composition and a production method thereof. The composition comprises the following components: 100 weight parts of polypropylene, 10-30 weight parts of ammonium polyphosphate, 2.8-8.3 weight parts of pentaerythritol, 2.8-8.3 weight parts of melamine cyanurate and 0.5-5 weight parts of montmorillonite. The total additional amount of ammonium polyphosphate, pentaerythritol and melamine cyanurate is at least 31 weight parts. The production method comprises the following steps: proportioning all components (including polypropylene, ammonium polyphosphate, pentaerythritol, melamine cyanurate and montmorillonite) at the given ratios, melting, mixing, extruding and granulating. The composition has better flame retardation, good processability and mechanical property. The production method is simple and reliable.

The invention discloses a high-entropy alloy with high strength and toughness and a preparation method thereof, and belongs to the field of metallic materials. The high-entropy alloy is AlaCrbFecNidVe according to a mole ratio; the method comprises: firstly, putting Al, Cr, Fe, Ni and V into a melting furnace, performing electric arc melting at a certain vacuum degree under the protection of a gas to obtain alloy liquid, and performing stirring and cooling to obtain an alloy ingot; and overturning the alloy ingot, and then performing electric arc melting, stirring and cooling to obtain the AlCrFeNiV high-entropy alloy. The high-entropy alloy is simple in structure, excellent in mechanical property, and relatively good in strength and toughness matching; and the method is simple and reliable, and is good in safety and high in economic value.

The invention relates to the field of chemical engineering, in particular to a high-performance waterborne inorganic paint and a preparation method thereof. The high-performance waterborne inorganic paint, provided by the invention, comprises the following ingredients in parts by weight: 20-35 parts of silica sol, 5-15 parts of a polymer solution, 5-15 parts of a pigment, 15-30 parts of a filling agent, 0.5-1.5 parts of a foam breaking agent, 1-2 parts of a coalescing agent, 0.05-0.5 part of a thickening agent, and 20-35 parts of water. The waterborne inorganic paint introduces an organic macro molecule solution, so as to optimize the ratio of pigment, the filling material, the foam breaking agent and the coalescing agent, and obtain the high-performance waterborne inorganic paint which is environment-friendly and has remarkably strong adhesion, good leveling property and glossiness property, as well as other characteristics; the preparation method is simple and reliable, and is low in manufacturing cost, thereby being suitable for industrial manufacture and application.

The invention discloses a manufacturing method for an Asia elephant specimen, comprising steps of peeling off the skin, measuring sizes of key parts of the elephant body, removing the fat, performing sterilization, performing salinization during tanning, performing preservation and immersion, applying oil, making a keel, making the prosthesis of the elephant according to the measured size of the key part of the elephant, working out the prosthesis of the elephant, covering skin and sewing, and finishing the manufacture of the specimen. The manufacturing method for the Asia elephant specimen is simple and low in cost.

The invention discloses a compound with antitumor activity, which is a compound shown as a formula I, and can be applied to preparation of an antitumor medicament and preparation of a medicament for preventing tumors. The invention further discloses a preparation method of the compound with antitumor activity. The method comprises the following steps of: performing reflux extraction on physalis pubescens L. with an extraction solvent to obtain an extracting solution; concentrating the extracting solution, diluting with water, and extracting with an organic solvent to obtain a dichloromethane extracting solution, wherein the organic solvent at least comprises dichloromethane; and concentrating the dichloromethane extracting solution, passing through a chromatographic column, eluting with an eluting system, and recrystallizing to obtain the compound with antitumor activity. The preparation method is simple and reliable, high operability and high efficiency are achieved, industrial mass production can be performed, popularization and application are facilitated, and a good application prospect is achieved.

The invention relates to a preparation method of a mesoporous carbon material, characterized by using ZnO as a template, using organic polymer of dispersible ZnO particles as a carbon source, such as polyacrylamide, and after charing the organic polymer at a high temperature, using organic acid or inorganic acid or alkali to remove the template ZnO to generate mesopores. The mesopores prepared by the invention have same size with the ZnO particles, and a Zn solution after dissolving can be used for synthesizing ZnO nanoparticles repeatedly, thus the purpose of reducing the cost is achieved.

The invention relates to a composite film electrode and a preparation method thereof. The electrode is a graded porous nano composite film which is composed of an insulating substrate, a first binding layer, a conductive gold layer, a second binding layer and a modified aluminum layer, wherein small holes with a hole diameter of 2-20 nm are uniformly distributed on the conductive gold layer according to a distribution density of 1010 / cm2-1012 / cm2, and the small holes with the hole diameter of 20-400 nm are uniformly distributed on the second binding layer and the modified material layer according to the distribution density of 109 / cm2-1012 / cm2; and the preparation method of the electrode comprises the following steps of: firstly, preparing a multi-layer composite film on the insulating substrate, then, performing anodizing and hole enlargement on the multi-layer composite film to implement that an aluminum layer becomes a porous alumina layer, a gold layer becomes a nano porous structure, the second binding layer becomes a porous oxide of tantalum, niobium or titanium, and cleaning and drying the multi-layer composite film to get a finished product of the graded porous nano alumina / gold composite film electrode. The graded porous nano alumina / gold composite film electrode has high in electroanalytical activity and the dual advantages of a nano porous gold and a porous anodizedaluminum; and the preparation method is simple and reliable, solves the defect of inconvenience in operation caused by high brittleness of an AAO, and fits for mass production.

The invention relates to an anti-swelling clay stabilizer and a preparation method thereof and belongs to the technical field of oil exploitation. The anti-swelling clay stabilizer is prepared from the following components in parts by weight: 1-3 parts of gellan gum, 2-5 parts of potassium fulvate, 5-10 parts of 1-butyl-3-methyl imidazole tetraborofluoride, 10-15 parts of a Gemini surfactant, 5-10 parts of polyethylene glycol, 0.5-3 parts of isopropanol and 18-25 parts of water. The preparation method of the anti-swelling clay stabilizer provided by the invention is simple and reliable and the anti-swelling clay stabilizer prepared has an extremely strong bonding force with clay minerals and is good in compatibility, high in anti-swelling efficiency and easy to popularize and apply.

The invention discloses a graphene modified glue solution and a preparation method and application thereof. The graphene modified glue solution is mainly prepared from a waterborne polyurethane adhesive, graphene and a dispersant. The graphene accounts for 0.1%-0.25% of the weight of the waterborne polyurethane adhesive, the dispersant accounts for 1%-2.5% of the weight of the adhesive, and the solid content of the waterborne polyurethane adhesive ranges from 30% to 50%. The modified water-based adhesive can effectively improve bonding performance and heat conduction performance; the preparation method is easy and convenient to carry out and reliable.

The invention relates to a method for preparing a super-macroporous high-specific-area polymer. The method includes obtaining a super-macroporous polymer through low-temperature freezing polymerization, and subjecting the super-macroporous polymer to post-crosslinking through free radical reaction or Friedel-Crafts alkylation reaction so as to obtain the super-macroporous high-specific-area polymer. The method further includes taking a divinyl benzene as a monomer, dimethyl sulfoxide as a solvent and a crystal as a pore-foaming agent, selecting a redox initiation system and polymerizing to obtain the super-macroporous polymer; taking the super-macroporous polymer as a precursor and dichloroethane as a solvent, adding a free radical initiator or ferric trichloride to perform post-crosslinking, carrying out thermostatic reaction in oil bath at 85 DEG C for 18 hours, washing and drying so as to obtain the super-macroporous high-specific-area polymer. The method is simple and reliable and simple in post-treatment. The super-macroporous high-specific-area polymer has a super-macroporous structure and a high specific area, the pore size range is mainly between 5-100 nm and 20-200 micrometers, and the maximum specific area can be up to 1214.19 m<2> / g.

The invention discloses a liquid phase chip kit used for early diagnosis of breast cancer, which primarily comprises: (1) 5-plex coated microsphere comprising a No.51 microsphere coated with an IL-6 capture antibody, a No. 38 microsphere coated with an IL-8 capture antibody, a No. 34 microsphere coated with a TNF-Alpha capture antibody, a No. 20 microsphere coated with a T-PSA capture antibody, a No. 32 microsphere coated with a VEGF capture antibody; (2) intermixture to detect antibodies, which is marked with biomarkers of IL-6, IL-8; TNF-Alpha, T-PSA and VEGF; (3) streptavidin phycoerythrin. The invention discloses a method to prepare the liquid phase chip kit. The liquid phase chip kit used for early diagnosis of breast cancer has the advantages of no side effect, high flux, multiple indices used for parallel detection, high sensitivity, high repetitiveness, quick and accurate detection, low cost and so on.

The invention discloses a lithium supplement additive and a preparation method thereof, and a lithium ion battery containing the lithium supplement additive. A lithium supplemental additive is a powerparticle, that median particle size D50 is greater than or equal to 0.1 mu m and less than or equal to 20 mu m, and the chemical formula is xLi 2O. YM. ZNaOb, wherein, y) 0, z) 0, 2x-Y-Z*a)0.1, b)0;M is one or more of Co, Mn and N is one or more of Co, Mn, Al and Ti. The lithium supplement additive is combined with metal lithium, Compared with organic lithium, organic lithium is more stable andsafer. When added in lithium ion battery, organic lithium can provide lithium source during the first charge, which can compensate the lithium consumption when the positive electrode and negative electrode form SEI film, improve the first discharge capacity, cycle performance and energy density, and is especially suitable for the negative electrode system with low first charge-discharge efficiency.

The invention belongs to the technical field of medicines and provides a cyclic-ahltin type triterpenoid saponin compound and a preparation method and application thereof. The cyclic-ahltin type triterpenoid saponin compound is prepared by the steps of: obtaining an extracting solution or extract liquor by using a flash extraction technology or a solvent extraction method; processing the extracting solution or the extract liquor by using a non-polar resin column to obtain crude saponin; quickly processing the crude saponin by using a silica gel flash column chromatography, and then carrying out solvent gradient elution, and further separating and purifying by using a medium-low pressure column chromatography or open ODS (Oxide Dispersion Strengthened) column chromatography and an HPLC (High Performance Liquid Chromatography) technology. An LC-MS technology is used for detecting the components of the cyclic-ahltin type triterpenoid saponin compound in the preparation process. The prepared cyclic-ahltin type triterpenoid saponin compound has better anti-tumor activity.

The invention discloses a high-entropy quinary alloy with good high strength and high plasticity matching performance. The chemical formula of the high-entropy quinary alloy is AlaCobCrcFedNie (a-e are molar ratios), wherein 1>=a>=0.5, 1.2>=b>=0.7, 1>=c>=0.4, 1>=d>=0.4, and 2.2>=e>=0.8. Furthermore, a:e is 1:1.2-2.5. Furthermore, a is 0.8, b is 1, c is 0.6, d is 0.7, and e is 1.1-2.0. Furthermore,the chemical formula of the alloy is Al0.8CoCr0.6Fe0.7Ni1.1, Al0.8CoCr0.6Fe0.7Ni1.5, Al0.8CoCr0.6Fe0.7Ni1.8, or Al0.8CoCr0.6Fe0.7Ni2.0. The high-entropy quinary alloy has high strength and high plasticity, and the problem that the strength-plasticity matching performance of a high-entropy alloy in the prior art is poor is solved. The invention further provides a preparation method of the high-entropy quinary alloy with the good high strength and high plasticity matching performance. The preparation method is simple, safe and stable.

The invention discloses a feed applicable to industrial aquaculture of tilapia, and a preparation method and a feeding method of the feed. The feed is prepared from corn protein powder, chicken powder, bean pulp, fermented rapeseed meal, fermented cottonseed meal, flour, soybean oil, fish oil, rice bran, mineral substances, vitamins and the like according to certain weight percent. The materials are prepared into granules by the steps of mixing, crushing, pelletizing, drying, screening and the like, and the granules are fed to the industrially cultivated tilapia according to the corresponding feeding method. The feed disclosed by the invention is made from the common materials, is low in cost, and is made by the simple and reliable preparation method; the raw materials are reasonable in proportion, and thus the feed can better meet the physiological needs of the industrially cultivated tilapia; the excrement of the tilapia is good in molding and unlikely to scatter, thus being discharged out of a culture system more easily. By virtue of the feeding method disclosed by the invention, ammonia and nitrogen emission can be reduced, the content of ammonia nitrogen and nitrite in a water body can be effectively reduced, and the resistance of the tilapia to streptococcus is enhanced.

The invention discloses a preparation method and an application of flaxseed polysaccharides with antiviral and immune activity. The preparation method adopting flaxseeds as a raw material comprises the following steps: crushing flaxseeds, carrying out shell-kernel separation, carrying out microwave assisted hot water extraction, carrying out Sevage technology protein removal, carrying out ethanol precipitation, freeze-drying to obtain crude flaxseed polysaccharides, and carrying out ion exchange column chromatography, carrying out Sephadex column chromatography, and carrying out ultrafiltration to prepare flaxseed sulfated polysaccharides. FHP-1 obtained in the invention has homogeneous composition, and the molecular weight is 2626kDa. Polysaccharide with sulfate and triple-helical structure are separated from the flaxseeds in the invention for the first time. Cell biology experiments prove that the polysaccharides can reduce expression of hepatitis B surface antigen and hepatitis B e antigen and inhibit replication of hepatitis B viruses, can activate immune response, and improves secretion of the tumor necrosis factor TNF-a, interleukins IL-6 and IL-12, and an inflammation factor NO by immune cells.

Reagent kit for predicting 5-hydroxytryptamine re-ingestion inhibitor medicinal effect contains erythrocyte lytic liquid, leukocyte lytic liquid, protein deposit, nucleic acid reserve liquid, PCR reactive mixed liquid with MgC12, dNTP and PCR cloning primer and indicator, DNA polymerase, positive proton, negative control, endonuclease buffer system, limited endonuclease, PCR water, 10X electrophoretic buffer liquid, bromphenol blue 0.25% and sugar solution w / v40%. It extracts gene DNA in biological sampler and has polymerase chain-reaction-limited enzyme fragment polymorphism PCR-RFLP analysis.

The invention discloses an injection containing sodium, potassium, magnesium, calcium and glucose and a preparation method of the injection. Every 1000 ml of injection contains 5-10 g of sodium chloride, 0.1-0.5 g of potassium chloride, 0.05-0.5 g of magnesium chloride hexahydrate, 1-5 g of sodium acetate trihydrate, 0.1-1 g of sodium citrate dehydrate, 0.1-2 g of calcium gluconate monohydrate, 5-20 g of anhydrous glucose, 0.5-2 g of antioxidant and appropriate water for injection, and a pH regulator solution is used for regulating the pH to be 4.5-6.0. The injection containing sodium, potassium, magnesium, calcium and glucose has the advantages that as appropriate antioxidant is added, the content of 5-hydroxymethyl furfural in the sterilized sodium, potassium, magnesium, calcium and glucose injection is effectively reduced; the sterilization time and injection preparation temperature are optimized, so that glucose being converted into 5-hydroxymethyl furfural at excess temperature is avoided, and the content of 5-hydroxymethyl furfural in the injection containing potassium, calcium and glucose is also effectively reduced; the preparation method is simple and reliable and is suitable for industrial production.

The invention discloses a doped lanthanum chromite film type thermocouple and a preparation method thereof, aiming at meeting requirements of measuring at high temperature under extreme environment. The technical solution of the invention is such that: a doped lanthanum chromite film type thermocouple includes two hot electrodes which are disposed on a ceramic substrate; the two hot electrodes are in mutually overlapped connection; the materials of the two hot electrodes individually adopt a lanthanum chromite film which is doped with one or a plurality of doping elements of Mg, Ca, Sr, Ba, Co, Cu, Sm, Fe, Ni and V; the lanthanum chromite films of the two hot electrodes are doped with different types of doping elements, or are doped with the same type of doping elements having different contents.