51results about "Phosphorus preparation" patented technology

The present invention provides a method for preparing high-stability two-dimensional black phosphorus. First, a phosphorus source and an iodine source are introduced into a reaction system for preliminary preheating and activation. After being fully activated in the raw material area of ​​the reaction system, they are slowly transferred to the crystal growth area of ​​the reaction system. The phosphorus source and the transport agent flow through the liquid to the catalyst and are fully converted in the intermediate formation area. The converted intermediate slowly moves to the crystal nucleation growth area to begin crystal nucleation and growth. After further sufficient reaction, the crystal nucleation growth point continues to extend and grow, and finally the black phosphorus crystal slowly nucleates and grows in blocks. After the crystal growth is completely cooled to room temperature, the unconverted raw materials are reused until they are finally converted into black phosphorus crystals and tail gas. The tail gas is absorbed and converted into other by-products. The use of high-temperature and high-pressure resistant pipelines can achieve efficient transportation of gaseous phosphorus, thereby extending the growth time of black phosphorus crystals and improving the growth efficiency of black phosphorus crystals.

The invention discloses a low-cost and green phosphorus coal composite negative electrode material and a preparation method thereof. The preparation method specifically comprises the following steps: pretreating phosphate ore and raw coal; mixing the phosphate ore powder with the raw coal powder to obtain a phosphorus-coal mixed precursor; feeding the phosphorus-coal mixed precursor into a fluidized bed reactor for reaction to generate mixed gas; introducing the mixed gas into a cyclone separator, and separating solid particle impurities; the phosphorus steam is converted into liquid phosphorus, residual phosphorus steam and other impurities are adsorbed, and primary separation of the phosphorus steam from CO and H2 is achieved; and mixing phosphorus steam and H2, introducing the mixture into a CVD reactor, adding the high-specific-surface coal matrix, carrying out a reaction, and carrying out washing and drying. According to the phosphorus-carbon composite material disclosed by the invention, phosphorus steam is uniformly deposited on the surface and pores of a high-specific-surface coal matrix; the porous structure of the high-specific-surface coal matrix provides an expansion buffer space for phosphorus, and meanwhile, part of phosphorus and oxygen-containing functional groups on the carbon surface form chemical bonds, so that the interface bonding strength is enhanced.

The present invention provides a solid electrolyte material that can suppress a decrease in filling efficiency. [Solution] A solid electrolyte material comprising a sulfide solid electrolyte containing lithium, sulfur, and phosphorus, and an organic compound, wherein the organic compound has two or more benzene rings, and the melting point of the organic compound is 82°C or lower.

The invention relates to a method for recovering silicon in the form of silicon tetrachloride, in which biochar having a silicon content of at least 1% by weight, expressed as% by weight of elemental silicon, is reacted with elemental chlorine at a temperature of 350 to 900 DEG C and the formed silicon tetrachloride is separated from the exhaust gas stream, preferably by condensation.

A method for producing phosphorus in which a reaction for forming gaseous phosphorus (g) by bringing phosphorus oxide generated by heating a liquid phosphoric acid compound into contact with a carbon material to reduce the phosphorus oxide and for condensing the gaseous phosphorus (g) to obtain liquid phosphorus (L) is conducted by a flow reaction with a nonoxidizing gas flow, wherein the reduction reaction of the phosphorus oxide is conducted in a carbon material-packed bed, and the condensation of the formed gaseous phosphorus (g) is substantially conducted in a condensation accelerator-packed bed which is disposed downstream of the carbon material-packed bed in contact with the carbon material-packed bed.

The invention relates to a method for synthesizing black phosphorus - polyglycerol (BP-PG) nanoparticles comprising the step of adding (100) black phosphorus (BP) nanoparticles, glycidol and a plurality of beads (10) to a chamber (21) of a milling device (20) and the step of rotating (200) the chamber (21) over a defined period of time. The invention also relates to a method for recovering a precious metal from a precious metal containing matrix comprising the step of providing (300) the precious metal containing matrix in the form of a solution containing dissolved precious metal ions and the step of adding (400) black phosphorus - polyglycerol (BP-PG) nanoparticles to the solution, wherein the black phosphorus - polyglycerol (BP-PG) nanoparticles are synthesized using the method for synthesizing black phosphorus - polyglycerol (BP-PG) nanoparticles.

This invention relates to the field of oil additives for power generation, specifically a method for in-situ preparation of black phosphorus nanoparticles (BPNPs) using PVA / PAAM interpenetrating network hydrogel as a microreactor and its application as a wear-resistant additive in lubricating oils. The confinement effect of the interpenetrating network hydrogel results in uniform BPNP size and high crystallinity, thus endowing BPNPs with excellent air / water / oil stability, with an oxidation rate of <5% within 7 days. Swelling allows RP / KI to permeate uniformly and be physically embedded in the network. Subsequently, under a nitrogen protective atmosphere, photolysis of iodine ions generates solvated electrons (e). ‑ (aq) restores RP to P ‑ P ‑ The BP crystal nucleus is formed by recombination, and the IPN three-dimensional nanochannels (pore size 30~120nm) confine and inhibit excessive growth of the crystal nucleus. At the same time, the PVA hydroxyl groups and PAAm amide groups passivate the BP surface in situ through hydrogen bonding / coordination, preventing oxidation.

This invention relates to a non-metallic porous carbon anode material, its preparation method, and its application. The preparation method includes: activating a carbon-containing raw material in a hydrogen-containing mixed gas to obtain porous carbon and a benzene-rich hydrocarbon gas; depositing the non-metallic source gas and the porous carbon in a primary deposition; and then depositing the non-metallic source gas and the benzene-rich hydrocarbon gas in a secondary deposition to obtain the non-metallic porous carbon anode material. The carbon-containing raw material is further de-ashed before use, or the porous carbon is de-ashed and then mixed. This invention achieves continuous preparation of porous carbon and non-metallic porous carbon anode materials by activating the carbon-containing raw material with hydrogen. The excess hydrogen generated in this process can be recycled to the hydrogen activation step for reuse. Hydrogen activation enables efficient deoxygenation of the carbon-containing material, avoiding the generation of other oxide impurities during the deposition of non-metals, effectively ensuring the safety of the deposition process. The benzene-rich hydrocarbon byproduct generated during the preparation of porous carbon can further carbonize the material, achieving efficient utilization of carbon resources.

The utility model discloses an ash bucket deslagging device for phosphorus sludge recovery treatment, which comprises a support frame, a stock bin and a blanking barrel, and is characterized in that the stock bin is arranged at the upper part of the support frame, the stock bin is of a cylindrical structure, an annular reinforcing rib is arranged outside the stock bin, the blanking barrel is arranged at the bottom of the stock bin, and a blanking valve is arranged at the lower part of the blanking barrel; a conveying groove is formed in the lower middle portion of the supporting frame, the bottom end of the discharging barrel is connected with the conveying groove, two conveying shafts are arranged in the conveying groove side by side, and a plurality of conveying blades are arranged outside the conveying shafts; the conveying motor is arranged at one end of the conveying groove and connected with one side of the gearbox through the coupler, the conveying shaft is installed on the other side of the gearbox, the conveying motor drives the conveying shaft to rotate, and dust in the stock bin can be efficiently and rapidly discharged.

This invention proposes a method for preparing black phosphorus nanosheets, comprising the following steps: Step 1, preparing an electrolyte, including adding tetrabutylammonium hexafluorophosphate to an organic solvent to obtain an electrolyte; Step 2, electrochemical cathode stripping, including immersing the anode and cathode in the electrolyte, applying a direct current, and reacting to obtain a precipitate, which is the black phosphorus nanosheet; the cathode comprises black phosphorus. This invention also proposes a black phosphorus nanosheet, a black phosphorus-modified interdigitated electrode and its preparation method, and a multifunctional flexible sensor incorporating the interdigitated electrode. The method for preparing black phosphorus nanosheets provided by this invention has high production efficiency and is expected to be applied to large-scale industrial production. The multifunctional flexible sensor can respond to breathing frequency, light, and strain with high responsivity, realizing the fabrication of multifunctional integrated devices.

The invention provides a method for recovering waste lithium iron phosphate powder, and relates to the technical field of solid waste resource recovery. The method comprises the following steps: mixing waste lithium iron phosphate powder with silicon powder, and carrying out silicothermic reduction under a vacuum condition to obtain steam (lithium and phosphorus steam) and solid residues (comprising silicon dioxide and silicon iron); carrying out condensation separation on the steam to respectively obtain lithium and phosphorus; and the solid residues are subjected to magnetic attraction separation, and ferrosilicon is obtained. According to the method, the waste lithium iron phosphate powder is recovered by adopting a method of combining vacuum metallurgy silicothermic reduction with condensation separation and magnetic attraction, no harmful gas and waste liquid are generated, the method is safe and environment-friendly, comprehensive recovery of Li, P and Fe is realized, the process is simple, and the metal recovery rate is high. Results of the embodiment show that when the waste lithium iron phosphate powder is recycled through the method, the reduction rate of lithium ranges from 98.67% to 99.97%, and the reduction rate of phosphorus ranges from 99.87% to 99.91%.

The application relates to a method for recovering liquid-phase phosphorus and acetic acid by co-hydrothermal carbonization of fish paste and cellulose acetate, and belongs to the technical field of waste resource utilization and clean energy preparation. The method comprises the following steps: (1) mixing fish paste and cellulose acetate according to a mass ratio of 1:3-3:1, and carrying out hydrothermal carbonization at 200-240 DEG C for 0.5-2 h; (2) carrying out solid-liquid separation on the hydrothermal carbonization product to obtain liquid products and solid products; (3) recovering liquid-phase phosphorus and acetic acid from the liquid products; and (4) using the dried solid products as clean solid fuel. The application realizes the collaborative treatment of fish paste and cellulose acetate through a single process, simultaneously completes the recovery of phosphorus and acetic acid and the preparation of solid fuel, does not need to add chemicals, and has the advantages of simple process flow, low cost and environmental friendliness.

The invention provides a preparation method of a two-dimensional nanometer black phosphorus-based cadmium sulfide-doped heterojunction material, and relates to the technical field of nanometer material photocatalysis. The method comprises the following steps: preparing a two-dimensional nano black phosphorus / red phosphorus composite material by taking red phosphorus as a raw material, and doping cadmium sulfide on the basis of the black phosphorus / red phosphorus composite material to construct the heterojunction. The two-dimensional nano black phosphorus-based cadmium sulfide-doped heterojunction material disclosed by the invention is increased in photocatalytic sites and increased in specific surface area, has efficient photocatalytic ability, and can be used for decomposing water to generate hydrogen.

The application discloses a preparation method of black phosphorus / molybdenum disulfide nanoflower composite materials and application of the black phosphorus / molybdenum disulfide nanoflower composite materials in detection of foodborne pathogenic bacteria, and has the characteristics that the preparation method comprises the following steps: (1) black phosphorus nanosheets are prepared by using a hierarchical centrifugation assisted liquid phase exfoliation method; and (2) the black phosphorus / molybdenum disulfide nanoflower composite materials are prepared by using a hydrothermal method: 10 ml of the black phosphorus nanosheet aqueous solution prepared in the step (1), 5 ml of an ammonium molybdate aqueous solution and 5 ml of a thiourea aqueous solution are sequentially transferred into a polytetrafluoroethylene-lined stainless steel autoclave, the mixture is allowed to react at 200 DEG C for 24 hours after ultrasonic treatment, and then the black phosphorus / molybdenum disulfide nanoflower composite materials are obtained by washing with ethanol and deionized water several times, and can be used for detection of foodborne pathogenic bacteria and preparation of antibacterial agents, and the black phosphorus / molybdenum disulfide nanoflower composite materials have the advantages that the detection sensitivity of the foodborne pathogenic bacteria is improved, and the black phosphorus / molybdenum disulfide nanoflower composite materials have the functions of photothermal and photocatalytic synergistic antibacterial.

The invention relates to a method for recovering phosphorus in the form of chloride, in which sewage sludge ash having a phosphorus content of at least 2% by weight, expressed as the weight percent of elemental phosphorus in the ash, is reacted with elemental chlorine in the presence of a carbon source at a temperature of 350 DEG C to 900 DEG C, and the formed phosphorus chloride is removed from the exhaust gas stream.

The present application belongs to the technical field of lubrication, and particularly relates to an organic-inorganic superlattice structure black phosphorus material and a preparation method and application thereof, and a lubricating coating and a preparation method thereof. The organic-inorganic superlattice structure black phosphorus material is obtained by an electrochemical intercalation reaction of black phosphorus as a negative electrode and a positive electrode in an electrolyte. The electrolyte comprises hexadecyl trimethyl ammonium bromide and an organic solvent. The hexadecyl trimethyl ammonium cation is embedded into the interlayer of the black phosphorus by an electrochemical intercalation strategy to form a CTA-BP organic-inorganic superlattice structure, and the black phosphorus is modified in lubricating performance. The technical defects of the prior art, such as the difficulty in balancing the low friction and the anti-wear performance of the black phosphorus, the poor chemical stability, and the short service life, are effectively solved. Meanwhile, the problems of the traditional black phosphorus friction modification technology, such as the high cost, the complex process, and the limited application, are overcome.

This invention relates to an in-situ stabilization method and apparatus for atomic-level manufacturing of two-dimensional black phosphorus based on controllable micro-explosion, belonging to the field of two-dimensional semiconductor materials and atomic-level precision manufacturing technology. This invention uses a phosphorus-based energetic compound as a phosphorus source-energy integrated precursor. Under the constraint of an array-type nano-confined microcavity, a controllable micro-explosion is synchronously triggered by a nanosecond laser. Combined with in-situ coating of hexagonal boron nitride and directional electric field modulation, the directional self-assembly of nanosecond-level highly stable two-dimensional black phosphorus is achieved, completely solving the industry pain points of easy oxidation and poor stability of traditional black phosphorus. The preparation cycle of this invention is reduced to less than 10 minutes, the product exhibits high room temperature carrier mobility, and a stable storage time in air of ≥30 days. It is 100% compatible with existing semiconductor production lines and is suitable for large-scale manufacturing in fields such as high-speed photodetectors, millimeter-wave devices, and biosensors.

The invention discloses purple phosphorus microcrystalline powder, a preparation method thereof and a semiconductor device. The method comprises the following steps: placing amorphous red phosphorus and iodine in a quartz tube; carrying out vacuumizing treatment and flame sealing on the quartz tube; and placing the flame-sealed quartz tube in a tubular furnace for heat treatment to obtain the purple phosphorus microcrystal powder. Therefore, direct synthesis of the purple phosphorus microcrystal powder is realized, a high-energy crushing process of block crystals is not needed, the energy consumption and the production cost of the purple phosphorus powder in industrial application are remarkably reduced, and the method has a good actual popularization value; the process is simple and convenient, raw materials are easy to obtain, introduction of toxic metal impurities is reduced, the prepared purple phosphorus microcrystal powder is high in purity and excellent in crystallization quality and can be directly used for practical application such as catalysis and flame retardance, and a technical foundation is laid for large-scale popularization of high-purity purple phosphorus in the fields of electronics, photoelectrons and the like.

The application discloses a preparation method of a black phosphorus / metal organic framework composite water splitting electrocatalyst, adopts an electrochemical exfoliation method and an ultrasonic exfoliation method in combination to prepare an ultrathin thin layer BP (FL-BP); the ultrathin thin layer BP is added into a methanol solution of cobalt acetate, a 2-methyl imidazole methanol solution is added while stirring, and then standing, centrifugation, alcohol washing and drying are carried out; the obtained product is heat treated under an inert atmosphere to obtain the black phosphorus / metal organic framework composite water splitting electrocatalyst; the application has the advantages of mild and safe reaction conditions, high product yield, low production cost, good economic benefits and application prospect; the obtained black phosphorus / metal organic framework composite water splitting electrocatalyst has a water splitting potential as low as 1.64 V under a current density of 10 mA cm ‑2 After 2000 cycles of water splitting electrocatalysis test, the overpotential only increases by 9 mV, and the defect of poor stability of black phosphorus nanosheet is overcome.

Provided is a method of preparing black phosphorus crystal. First, one area of a double-opening reactor is used as the feedstock area, the other area is used as the nucleation area, and the middle area is used as a transition section, and the feedstock area is sealed, the phosphorus feedstock and the transport agent are weighed and placed inside the feedstock area under an inert atmosphere, then the nucleation area is sealed, the first step of heating reaction is performed in the reactor through an optimized temperature-control program, when the reaction is complete, monoclinic phosphorus crystals are prepared in the feedstock area. Then the nucleation area of the reactor is started, the weighed catalyst is placed inside the feedstock area under an inert atmosphere, and the nucleation area is sealed, and then the second step of a heating reaction is performed in the reactor through an optimized temperature-control program.

The present invention addresses the problem of providing a novel method for producing yellow phosphorus. As a means of solving said problem, the present invention provides a method for producing yellow phosphorus which includes a step for obtaining yellow phosphorus by reducing phosphoric acid and / or phosphate by using a silicon material.

The invention relates to a modified black phosphorus nanosheet as well as a synthesis method and application thereof. Asphaltene in thick oil is dispersed by grafting a copolymerized oil-soluble polymer on one side of the black phosphorus nanosheet, so that the viscosity of the thick oil is reduced, and meanwhile, the acting force between the modified black phosphorus nanosheet and crude oil is also increased; the hydrophilic polymer grafted on the other side faces water, so that the modified black phosphorus nanosheet is stabilized at an oil-water interface to form an emulsion; the black phosphorus nanosheet is used as a core, the polymer is used as a shell, and good salt resistance and temperature resistance are achieved; meanwhile, the modified black phosphorus nanosheet is used as a thick oil viscosity reducer, and the self-demulsification effect can be achieved by adjusting the pH value of produced liquid.

BPQDs@Fer1, its preparation method, and applications demonstrate that it can simultaneously scavenge excess ROS and efficiently deliver Fer-1. Through a dual mechanism of ROS scavenging and lipid peroxidation inhibition, it synergistically inhibits ferroptosis, effectively mitigating ischemia-reperfusion injury and subsequent rejection after kidney transplantation. This BPQDs@Fer1 uses black phosphorus quantum dot BPQDs as a carrier, loaded with the ferroptosis inhibitor Ferrostatin-1. The average particle size of the black phosphorus quantum dots is less than 20 nm.

The invention discloses a method for preparing a core-shell structure catalyst and applying the core-shell structure catalyst to black phosphorus crystal preparation, and belongs to the field of material synthesis. The method specifically comprises the following steps: synthesizing a polymer-metal catalyst composite material in an inorganic solvent or an organic solvent, drying, placing red phosphorus, a core-shell structure catalyst and a transport agent at a raw material end according to a certain proportion, and carrying out high-temperature treatment to obtain the high-quality black phosphorus at a nucleation end. Wherein the core-shell structure catalyst takes a polymer as a shell layer and a metal-B as a core, compared with a pure catalyst, the polymer of the shell layer improves the reaction participation temperature of the catalyst, and B in the core further improves the reaction activity of the catalyst metal, so that the problem that the reaction participation temperature of each material in the heating stage is different when black phosphorus is amplified to be prepared to be more than 30kg of a system is solved; therefore, the problems that the materials are not fully contacted in the reaction process, the volatilization rate of the materials is low and the hardening condition is serious are solved. Through construction of the core-shell structure, the material volatilization rate of the raw material end can be further improved, and the black phosphorus crystal quality is improved.

The application relates to the technical field of phosphorus chemical engineering new materials, in particular to a one-step synthesis of a supported Sn 24 P 19.3 I8 catalyst. The application takes a phosphorus source, tin powder, iodine and a carbon additive as raw materials, and a supported Sn 24 P 19.3 I8 catalyst is prepared through one-step solvothermal reaction. The method not only simplifies the preparation process of the catalyst, but also significantly improves the preparation efficiency and scale of the supported Sn 24 P 19.3 I8 catalyst, reduces the energy consumption in the production process, improves the catalytic activity and stability of the catalyst, has important significance for promoting the large-scale and efficient preparation of black phosphorus, lays a catalyst foundation for developing more new elemental phosphorus, and promotes the market promotion and industrialization development of phosphorus chemical engineering new materials.

The invention discloses a BPNs chemiluminescence probe, a BPNs chemiluminescence probe loaded scopoletin composite material and a chemiluminescence detection method of the BPNs chemiluminescence probe loaded scopoletin composite material. The BPNs chemical light-emitting probe synthesized through water bath ultrasonic wave loads scopoletin through hydrogen bond interaction to obtain the composite material, and the composite material has efficient active oxygen scavenging capacity and reacts with potassium permanganate to generate a strong chemical light-emitting signal. On the basis, a chemiluminescence detection platform of the BPNs / scopoletin is constructed. The method has the advantages of high sensitivity, low detection cost, simplicity and convenience in operation and the like.

The invention relates to a method for preparing high-yield black phosphorus by using a P-Fe-Sn alloy catalyst based on ferrophosphorus slag, which comprises the following steps: carrying out pickling soaking, reduction heat treatment and purification on ferrophosphorus slag to obtain a Fe-P intermediate, and carrying out melt alloying on the Fe-P intermediate and elemental tin according to a reasonable ratio to obtain the P-Fe-Sn alloy catalyst; red phosphorus is used as a phosphorus source, and under the action of the catalyst, reaction is carried out for 6-24 hours at 400-600 DEG C in an inert atmosphere through a gas-phase transmission method, so that oriented growth of black phosphorus is realized. The phosphorus iron slag is used as a raw material to prepare the efficient catalyst, the phosphorus iron slag is converted into a P-Fe-Sn alloy catalyst with higher value by utilizing the unique chemical thermal stability of iron phosphide and combining with the characteristic of preparing black phosphorus through catalysis of Sn, and the use proportion of the catalyst Sn is reduced; the prepared P-Fe-Sn alloy catalyst has excellent catalytic activity, and high-yield synthesis of black phosphorus can be realized. The black phosphorus prepared by the method is good in quality, high in crystallinity and low in equipment requirement, is suitable for large-scale production, and can provide technical support for industrial application of the black phosphorus.

The utility model relates to the technical field of high-purity phosphorus preparation, and discloses a high-purity phosphorus preparation device without a flow dead angle, which comprises a catalysis pipe, a yellow phosphorus feeding pipe fixedly connected to the top of the catalysis pipe, a bromine liquid feeding pipe fixedly connected to the top of the catalysis pipe, a nitrogen inlet pipe fixedly connected to the top of the catalysis pipe, and a nitrogen outlet pipe fixedly connected to the top of the catalysis pipe. A stirring and filtering mechanism is arranged at the bottom of the catalysis pipe, a waste pipe is arranged at the top of the stirring and filtering mechanism, hydrogen is subjected to secondary filtering through a filter screen through the arranged stirring and filtering mechanism, impurities in the hydrogen are prevented from influencing the reaction effect, then a first motor is started, the first motor drives a first bevel gear to rotate, and the waste pipe is arranged at the top of the stirring and filtering mechanism. The first stirring frame and the second stirring frame rotate reversely, sufficient combination of phosphorus bromide and hydrogen is further guaranteed, phosphorus bromide and hydrogen (H) generate high-purity yellow phosphorus and hydrogen bromide (HBr), the reaction rate is further increased, and the overall production efficiency of the device is improved.

The invention relates to the technical field of preparation of novel photoelectric semiconductor materials, in particular to a flow field-temperature field coordinated regulation black phosphorus preparation method for short-distance transportation, which adopts a reaction system to realize black phosphorus preparation. The reaction system comprises a multi-temperature-zone pit furnace, a metal reactor and a heat transfer component arranged in the metal reactor; the method comprises the following steps: putting red phosphorus, tin and a tin-iodine compound as preparation raw materials into a metal reactor, and carrying out heat treatment at high temperature by adopting a multi-temperature-zone pit furnace to prepare the black phosphorus. According to the method, the crystallinity and the purity of the product are remarkably improved, the overall energy consumption of the system is reduced while the kilogram-level preparation of the black phosphorus is realized, and a reliable equipment foundation is provided for large-scale and controllable synthesis of the black phosphorus.

The present invention provides a black phosphorus / carbon nanotube composite material, a preparation method therefor, and a use thereof. The preparation method comprises the following steps: (S101) preparing a black phosphorus nanosheet solution by means of a stepwise centrifugation-assisted liquid-phase exfoliation method; (S102) preparing a carbon nanotube solution by means of a liquid-phase exfoliation method; and (S103) preparing a black phosphorus / carbon nanotube composite material by means of a hydrothermal method, wherein the black phosphorus / carbon nanotube composite material prepared by means of a chemical synthesis method comprises black phosphorus and single-walled carbon nanotubes which are closely attached to each other, a three-dimensional network constructed by the carbon nanotubes well covers the surface of black phosphorus nanosheets, and the surfaces of the carbon nanotubes are filled with active electrons, so that a more sensitive detection result can be acquired, the Raman detection limit can be reduced, and the black phosphorus / carbon nanotube composite material is suitable for the detection of urinary tract bacteria.