44results about How to "Solve urgent problems" patented technology

The disclosed measuring apparatus and method for frictional moment comprise: the target bearing with diameter as D is suspended a segment nylon wire with ends connected to weight and dynamometer respectively, when bearing static, the show value on dynamometer as A1 balances to the weight; if rotating toward one direction by some rate, the show value increases to A2, and the formula M=(A2-A1) .D / 2 can express the corresponding frictional moment. This invention is reliable, simple, and well practical.

The invention discloses a large power thick film circuit high temperature sintering resistor paste for aluminium nitride base materials, and a preparation method thereof. The thick film resistor paste includes an inorganic bonding phase, a composite function phase, and an organic carrier, wherein an inorganic bonding phase is formed by SiO2, B2O3, ZnO, Al2O3, MgO, nucleus agent, and rare earth oxide system microcrystalline glass powder; the composite function phase is mixed powder of spherical silver powder, sheet shape silver powder, and nanometer palladium powder; and the organic carrier is formed by organic solvent, high-molecular thickening agent, dispersant, antifoaming agent and thixotropic agent. The preparation method comprises the steps: inorganic bonding phase preparation, composite function phase preparation, organic carrier preparation and resistor paste preparation. The paste has high thixotropy and fluidity, and the microcrystalline glass powder and the conductive phase do not react with the aluminium nitride base materials, and the sintered resistance layer has the advantages of being smooth and compact in structure, being high in adhesive force, being aging resistant, being adjustable in sheet resistivity, being lower and adjustable in the resistance temperature coefficient and being high in printing sintering characteristic.

The invention discloses a water-free odor-resistant vehicle-mounted toilet for pony cars. The water-free odor-resistant vehicle-mounted toilet comprises a container, a cover, a miniature fan, a high polymer material opening type packaging bag, a pipeline and an adsorption material layer which are arranged on a pony car seat, wherein the pony car seat is provided with a pony car cushion, a groove is formed on the pony car seat and positioned below the pony car cushion, the container is arranged in the groove, the cover plate is arranged on the top of the container for sealing the container, the cover plate is positioned below the pony car cushion, the high polymer material opening type packaging bag is arranged inside the container, the adsorption material layer is arranged at the bottom of the high polymer material opening type packaging bag, one side of the upper part of the container is provided with a mounting hole for mounting the miniature fan, and the miniature fan is arranged in the mounting hole, and exhausts air inside the high polymer material opening type packaging bag out of the car through the pipeline. The water-free odor-resistant vehicle-mounted toilet can effectively solve the problem of urgency of urination of old people, children or patients under the condition that the car cannot be randomly stopped or the car is subjected to traffic jam, is convenient to clean and does not occupy space.

The invention discloses a thick film circuit rare-earth electrode slurry based on a stainless steel base material. The thick film circuit rare-earth electrode slurry comprises a compound function phase, an inorganic binding phase and an organic carrier, wherein the compound function phase consists of nano silver powder, palladium powder and a rare earth oxide; the inorganic binding phase consists of SiO2, CaO, B2O3, Al2O3, Bi2O3 and a nucleation agent; and the organic carrier consists of an organic solvent, macromolecule resin, a dispersing agent, a defoaming agent and a thixotropic agent. A preparation method of the thick film circuit rare-earth electrode slurry comprises the following steps: preparing the compound function phase; preparing the inorganic binding phase; preparing the organic carrier; and preparing the electrode slurry. The thick film circuit rare-earth electrode slurry prepared by the invention is good in electrical conductivity, high in adhesive force, high in weldability, high in welding dissolution resistance, good in printing and sintering characteristics and high in environmental protection capability, is matched with the stainless steel base material, and is good in wettability and compatibility with dielectric slurries and resistance slurries.

The invention discloses a thick film circuit medium temperature sintered silver electrode slurry for an aluminium alloy substrate and a preparation method thereof. The electrode slurry comprises an inorganic bonding phase, spherical silver powders, flake silver powders and an organic carrier. The inorganic bonding phase is formed by seven materials which comprise Bi2O3, B2O3, CaO, ZnO, K2O, a nucleating agent and a rare earth oxide. The organic carrier is formed by five materials which comprise an organic solvent, a polymer thickening agent, a dispersing agent, a deforming agent and a thixotropic agent. The preparation method of the electrode slurry comprises the steps of (a) inorganic adhesive phase preparation, (b) organic carrier preparation and (c) electrode slurry preparation. The electrode slurry has good thixotropy and fluidity and low sintering temperature, a sintered electrode has the advantages of a smooth structure, compactness, no crack, no pinhole, no bubble, lead-free and environment-friendliness, and at the same time the sintered electrode has the advantages of strong adhesion, aging resistance, low resistance and excellent printing characteristic and sintering characteristic.

The invention discloses a method for recovering gold and copper from a waste mobile telephone, which comprises the following steps: 1) processing a mainboard of a waste mobile telephone into fragments smaller than 1cm; 2) adding the fragments into a supercritical water oxidation reaction device, adding deionized water and 30% hydrogen peroxide, sealing, and controlling the solid-to-liquid ratio of the reactants to be (1:5)-(1:30)g / ml; 3) heating to 250-400 DEG C, controlling the pressure to be 12-30MPa by means of a manual pressurization device, reacting for 30-180 minutes, and then stopping heating; 4) after the reaction is completed, cooling to room temperature, then opening a reaction kettle, performing solid-liquid separation, soaking the solid phase in a 0.5-3mol / L sulfuric acid solution for 5-40 minutes, filtering, vaporizing to concentrate and crystallize the filtrate, and recovering a CuSO4 crystal product; and (5) drying the surplus solid residue, then soaking in a potassium iodide-iodine solution for 30-180 minutes, filtering to obtain a gold concentrated solution, and recovering.

The invention discloses an aluminum alloy substrate thick film circuit middle-temperature sintering dielectric paste and a preparation method thereof. The preparation method is used for preparing the aluminum alloy substrate thick film circuit middle-temperature sintering dielectric paste. The aluminum alloy substrate thick film circuit middle-temperature sintering dielectric paste comprises the following materials in part by weight: 60%-80% of lead-free microcrystalline glass powders, 1%-10% of rare earth oxide and 19%-30% of organic bonding phase, wherein the lead-free microcrystalline glass powders are formed by SiO2, Bi2O3, B2O3, ZnO, K2O, SrO2 and CaO; and the organic bonding phase is a mixture formed by an organic solvent, a high-polymer thickener, a surfactant, a plasticizer, a dispersant, an antifoaming agent and a thixotropic agent. A dielectric layer formed by printing the dielectric paste on an aluminum alloy substrate has the advantages of large adhesive force, large breakdown strength and high insulation resistance, and is capable of being compatible with a thick film circuit of the aluminum alloy substrate with a resistance paste and an electrode paste.

The invention discloses a hydraulic transmission and automatic control stepless speed regulator, which comprises an enclosure, a speed regulator component, an overrunning clutch and a speed regulator component brake device, wherein the speed regulator component comprises an inner shell, a speed regulator input shaft and a speed regulator output shaft; a two-way hydraulic variable pump, a constant displacement hydraulic motor, a variable control driving device and a control system are arranged in the inner shell; the two-way hydraulic variable pump is connected in series with the constant displacement hydraulic motor; the two-way hydraulic variable pump, the constant displacement hydraulic motor and two oil passages communicated with the two-way hydraulic variable pump and the constant displacement hydraulic motor form a closed loop; a buffer cavity is connected to each of the two oil passages connected with the two-way hydraulic variable pump and the constant displacement hydraulic motor; in addition, a second hydraulic electromagnetic valve is arranged between an oil port of the two-way hydraulic variable pump and an oil port of the constant displacement hydraulic motor; a first hydraulic electromagnetic valve and the second hydraulic electromagnetic valve are electrically connected with the control system. The hydraulic transmission and automatic control stepless speed regulator is simple and compact in structure, low in manufacturing cost, continuous in transmission ratio, high in bearing capacity, high in transmission efficiency, safe, reliable and long in service life.

The invention provides a detection system of a light distribution characteristic of an ellipsoid unit. The detection system comprises a rotary table for placing a plurality of ellipsoid units, and further comprises a rotary part, a positioning locking part, a picking-placing part, a light detection signal transmitting part, a light type collecting part and a control part, wherein the rotary part comprises a servo controller, a servo motor and a main shaft; the positioning locking part comprises an approach switch set, a position encoding bolt set and a positioning air cylinder on the rotary table, a positioning pin and a positioning hole on the rotary table; the picking-placing part comprises a one-way electric air valve, a clamping claw air cylinder, an air faucet, and a clamping claw air opening and a clamping claw on the rotary table; the light detection signal transmitting part comprises an LIN (Local Interconnect Network) controller, a CAN (Controller Area Network) controller and an electric mortiser plug; the light type collecting part comprises a convex lens, an imaging screen and a camera, and is used for obtaining light type distribution images of the ellipsoid units; and the control part comprises an industrial personal computer and a digital I / O (Input / Output) card connected with the industrial personal computer, and is used for controlling the rotary part, the positioning locking part, the picking-placing part, the light detection signal transmitting part and the light type collecting part, and analyzing the light type distribution images to obtain a detection result of the light distribution characteristic.

The invention discloses a resistance slurry and a preparation method thereof, which are prepared from the following raw materials in parts by weight: 50-100 parts of a conductive phase, 100-150 parts of an inorganic phase, 200-500 parts of an organic phase, and 25-50 parts of an auxiliary agent Parts; wherein: the conductive phase is 20‑30% flake graphite powder, 40‑50% ruthenium dioxide powder, 50‑60% nano silver powder; the inorganic phase is 22‑60% silicon oxide, 13‑30% calcium oxide, 5‑60% 23% barium oxide, 12‑28% antimony trioxide, 15‑25% phosphorus pentoxide; organic phase is 16‑36% butyl carbitol, 21‑35% butyl carbitol acetate, 18‑25% 28% tributyl citrate, 7-12% ethyl cellulose, 6-18% hydrogenated castor oil, 0-8% polyamide wax, 18-30% silicone resin; additives are 16-55% nano Carbon-based conductive filler, 24‑48% ultra-fine base metal alloy powder conductive filler; the resistance paste of the present invention has strong adhesion to the substrate and is resistant to aging. The resistance prepared by the resistance paste has been tested and analyzed, showing resistance The performance is good, and the process requirement of the method is simple, and the manufacturing cost is low.

The invention discloses a battery pack sandwich shell with a negative poisson ratio layered quadrilateral energy absorption structure. The battery pack sandwich shell comprises a shell and an energy absorption structure; the energy absorption structure comprises energy absorption units and inverted energy absorption units, and the inverted energy absorption units are arranged between every two adjacent energy absorption units; each energy absorption unit comprises a first energy absorption cell body and a second energy absorption cell body arranged in the first energy absorption cell body; the first energy-absorbing cell body is an isosceles triangle with a concave bottom edge, the concave angle theta1 of the bottom edge is an obtuse angle, and the vertex of the concave angle is located on the angular bisector of the vertex angle of the first energy-absorbing cell body; the second energy-absorbing cell body is an isosceles triangle with a concave bottom edge, the concave angle theta2 of the bottom edge is an obtuse angle, the two bevel edges of the second energy-absorbing cell body are parallel to the two bevel edges of the first energy-absorbing cell body respectively, and a gap is reserved between the concave bottom edge of the second energy-absorbing cell body and the concave bottom edge of the first energy-absorbing cell body; and the three vertexes of the second energy absorption cell body are connected with the three vertexes of the first energy absorption cell body through linear connecting walls correspondingly. The shell is simple in structure and has both the energy absorption effect and the impact resistance.

The invention relates to a disease-preventive insecticide natural mineral fertilizer, which is characterized by comprising the following raw materials in parts by weight: 15 parts of Potassium rock, 11 parts of calcium superphosphate, 33 parts of pumice stone, 31 parts of calcite, 28 parts of Stone I am tamino, 8 parts of ammonium nitrate, 4 parts of azadirachtin, 3 parts of sanguinarine, 0.01 part of isodecyl neopentanoate, 0.02 part of isopropyl palmitate, 0.9 part of adhesive and 4 parts of stabilizer; the fertilizer further comprises 0.3-0.8 part by weight of insecticide. The disease-preventive insecticide natural mineral fertilizer has good prevention and control effect, and is universe in prevention types and environmentally friendly, can efficiently promote the growth of crops. The preparation method is simple and convenient to use, and the disease-preventive insecticide natural mineral fertilizer does not need to be frequently used to achieve good effect.

The invention discloses a measuring tool for measuring an aluminum alloy ring and a measuring method, wherein the measuring tool comprises a hot-state measuring long ruler and a cold-state measuring template, the main body of the hot-state measuring long ruler is long angle steel, one end of which is provided with a locating pin which is vertical to the angle steel, and the other end of the angle steel which is provided with the locating pin is fixed with a one-meter steel ruler. The whole long ruler is transmitted according to a national standard length value transmission system by adopting a direct-measuring method, and the error of the long ruler is calibrated. The cold-state measuring template comprises a square framework and an aluminum alloy standard round ring which is fixed on the framework. By using the two methods, the problems of hot-state measurement and cold-state measurement of Phi 5000mm-grade aluminum alloy forging parts are solved, and conditions are created for rapidly and accurately determining the ring size, the form and position tolerance and the allowance, thus solving the problems that are badly in need of solution in production.

The invention discloses a reactive dye colorfastness-to-bleeding improving agent, as well as a preparation method and application thereof. The reactive dye colorfastness-to-bleeding improving agent isprepared from the components: 50 to 70 parts of component A, and 30 to 50 parts of component B, wherein the component A comprises 10 to 30 parts of acrylamide, 5 to 10 parts of urea, 10 to 30 parts of methacrylic acid, 5 to 15 parts of stearic acid, 10 to 40 parts of polyethylene polyamine, 10 to 30 parts of distilled water, 5 to 15 parts of ammonium chloride, and 0.5 to 2 parts of initiator; thecomponent B comprises 5 to 10 parts of non-ionic surface active agent, 20 to 30 parts of quaternary ammonium salt, 40 to 80 parts of distilled water, and 1 to 5 parts of acidifier. The invention further provides the preparation method and the application of the reactive dye colorfastness-to-bleeding improving agent. According to the reactive dye colorfastness-to-bleeding improving agent, as wellas the preparation method and the application thereof provided by the invention, a dye is firmly fixed to the surface of a fabric, the adverse effect of metal ions on colorfastness to bleeding is effectively avoided, the surface tension of water is greatly reduced, the reactive dye is uniformly distributed on the fabric, a dyeing effect is good, the use performance is excellent, and the cost performance is high.

An external Chinese medicine plaster, especially for treating empyrosis. It is prepared by garden burnet, bee glue and balsam proportionally. The plaster could stanch bleeding, disinfecting and preventing infection.

The invention relates to a method and device for receiving and processing multipath emergent calls, wherein the method comprises the steps of: 1, connecting a fixed station with an intelligent network / train number server, and executing the step 2; 2, obtaining information of the fixed station by the intelligent network / train number server, and executing the step 3; 3, connecting the fixed station with a DCS (Decentralized Control System) server, and executing the step 4; and 4, logining the DCS server by the fixed station through a user name and a password, and executing the step 5, and the like. The device comprises the intelligent network / train number server, the DCS server, the fixed station and a local area network, wherein the intelligent network / train number server is connected with the DCS server through the local area network, and the fixed station is respectively connected with the intelligent network / train number server and the DCS server through the local area network. Compared with the prior art, the invention has the advantages of improving the working efficiency, furthest lowering the adverse impact generated by emergent events, ensuring line smoothness and safety, and the like.

An online and offline comprehensive interactive smart supermarket system and method of large data management are disclosed. An online module, an offline module, a large data analysis module and an interactive development module are included. The online module means a network platform linked with offline. A user can carry out online shopping and can be interacted with a supermarket. The offline module is an offline supermarket which is divided into a commodity display area and a commodity extraction area so that the different needs of a customer can be satisfied. The large data analysis modulecan know useful information through analyzing user data. The interactive development module gives a proposal authority to each customer becoming a member so that the smart supermarket becomes a resultof joint construction of many customers.

The invention relates to a silkworm breeding sterilizing machine, in particular to a portable electric dusting and sterilizing machine using powdered silkworm drug. Sterilization is an indispensable and important link during silkworm breeding, and the powdered silkworm drug is used almost every day but is corrosive and irritating generally; according to manual drug spraying, working efficiency is low and drug is sprayed unevenly, killing effect cannot be implemented on airborne pathogens in a silkworm breeding chamber, and importantly, human body organs are damaged in different degrees after contacting with the silkworm drug for long periods. The portable electric dusting and sterilizing machine can be widely applied into silkworm breeding by using the powdered silkworm drug to sterilize, and accordingly manual drug spraying is replaced. The silkworm breeding sterilizing machine is characterized in that air flow produced by a centrifugal type electric blower drives the powdered silkworm drug to spray rapidly and evenly, rapid disinfection and sterilization are performed on silkworms, silkworm rearing beds and in the environment, and manual sterilizing operation is replaced. The silkworm breeding sterilizing machine is mainly applied to an electrical sterilizing machine using the powdered silkworm drug for sterilizing during silkworm breeding.

The invention relates to an electronic approving system and its mobile urging method which is a mobile approving mould and method to inform the division chief approve the electronic spreadsheet. The mobile urging method of the electronic approving system includes steps as following: generating approving wrap-up based on the content of the electronic spreadsheet; gaining the mobile telephone number of the relative approving division chief from the human database; contacting the message service center; the approving wrap-up will be transferred to the corresponding mobile device with the mobile telephone number by the message service center, the approving division chief can execute the approving action. The electronic approving system includes: a human information database, an approving database, a passing approving implement mould, a monitor mould and message receiving and sending mould. The invention can increase the efficiency of the approving further, and improve the approving flow and operating efficiency; it is very suit for application.

The invention discloses a portable toilet, comprising an upper cover, a rear plate, a left side plate and a right side plate which can be folded together, and further comprising a left curtain, a right curtain, a front curtain, a rear curtain and a top cover which are made of a rainproof fabric, wherein the upper cover is provided with an excrement opening, a plastic bag is sleeved below the excrement opening, a cavity is formed in each of the left and right side plates, and the left and right curtains are respectively arranged in the cavities of the left and right side plates; the front curtain, the rear curtain and the top cover are connected into a whole and are all arranged in a cavity of the rear plate; two telescopic rods are respectively arranged in the left and right side plates; and two through holes are formed in one side of the upper cover approaching the rear plate, and are matched with the telescopic rods approaching one side of the rear plate in the left and right side plates. The portable toilet is simple in structure, can be folded to facilitate carrying, and can solve the problem of urgency of urination during long journey or outdoor playing.

The invention relates to a multi mode approving system and its method which is used to provide approving action for the division chief. The multi mode approving method includes steps as following: the corresponding approving flow information which includes approving chief is gained according to the electronic spreadsheet; affirming the approving condition of the electronic spreadsheet; when the approving condition is not approved, affirming the approving time limit; and when it comes to the approving time limit, generating approving wrap-up based on the content of the electronic spreadsheet and gaining the mobile telephone number of the relative approving division chief from the human database, then it will contact the message service center, the approving wrap-up will be transferred to the corresponding mobile device with the mobile telephone number by the message service center, the approving division chief can execute the approving action. The multi mode approving system includes: human information database, approving database, passing approving implement mould, monitor mould and message receiving and sending mould. The invention can increase the efficiency of the approving, and it is very suit for application.

The invention provides a urination urgency handling device. The urination urgency handling device comprises an underpants main body which is provided with an absorber for absorbing urine, a guiding device and a storage device, wherein the absorption device is fixedly connected with the underpants main body, and directly faces the private parts of a human body; the guiding device comprises a guide pipe which is connected with the absorber; the guide pipe is further connected with a pumping unit; the storage device comprises a urine storage bag which is connected with the guide pipe. The urination urgency handling device can be worn any time and used for a long time, and is especially suitable for adults under the circumstances that no toilet can be found away from home, and the urination urgency handling device is capable of solving the problem of urination urgency, and can be used continuously by changing the urine storage bag; in short, the urination urgency is very practical and convenient, portable, light and comfortable, and can be worn instead of underpants.

The invention provides a urination urgency handling device. The urination urgency handling device comprises an underpants main body which is provided with an absorber for absorbing urine, a guiding device and a storage device, wherein the absorption device is fixedly connected with the underpants main body, and directly faces the private parts of a human body; the guiding device comprises a guide pipe which is connected with the absorber; the guide pipe is further connected with a pumping unit; the storage device comprises a urine storage bag which is connected with the guide pipe. The urination urgency handling device can be worn any time and used for a long time, and is especially suitable for adults under the circumstances that no toilet can be found away from home, and the urination urgency handling device is capable of solving the problem of urination urgency, and can be used continuously by changing the urine storage bag; in short, the urination urgency is very practical and convenient, portable, light and comfortable, and can be worn instead of underpants.

The invention relates to a two-step SERS (Surface Enhanced Raman Scattering) detection method for judging novel coronavirus infectivity in an environment, which comprises the following steps: selecting an SERS enhanced substrate, carrying out SERS detection on SARS-CoV-2 S protein and RNA (Ribonucleic Acid), and constructing a judgment standard according to the difference of SERS signals of the SARS-CoV-2 S protein and RNA; and performing classification treatment on Raman spectrums obtained by performing two-time SERS detection on a new coronavirus sample existing in the environment in combination with a machine learning method so as to judge the infectivity of the new coronavirus existing in the environment.

The disclosed measuring apparatus and method for frictional moment comprise: the target bearing with diameter as D is suspended a segment nylon wire with ends connected to weight and dynamometer respectively, when bearing static, the show value on dynamometer as A1 balances to the weight; if rotating toward one direction by some rate, the show value increases to A2, and the formula M=(A2-A1) .D / 2 can express the corresponding frictional moment. This invention is reliable, simple, and well practical.

The invention discloses a hydraulic transmission and automatic control stepless speed regulator, which comprises an enclosure, a speed regulator component, an overrunning clutch and a speed regulator component brake device, wherein the speed regulator component comprises an inner shell, a speed regulator input shaft and a speed regulator output shaft; a two-way hydraulic variable pump, a constant displacement hydraulic motor, a variable control driving device and a control system are arranged in the inner shell; the two-way hydraulic variable pump is connected in series with the constant displacement hydraulic motor; the two-way hydraulic variable pump, the constant displacement hydraulic motor and two oil passages communicated with the two-way hydraulic variable pump and the constant displacement hydraulic motor form a closed loop; a buffer cavity is connected to each of the two oil passages connected with the two-way hydraulic variable pump and the constant displacement hydraulic motor; in addition, a second hydraulic electromagnetic valve is arranged between an oil port of the two-way hydraulic variable pump and an oil port of the constant displacement hydraulic motor; a first hydraulic electromagnetic valve and the second hydraulic electromagnetic valve are electrically connected with the control system. The hydraulic transmission and automatic control stepless speed regulator is simple and compact in structure, low in manufacturing cost, continuous in transmission ratio, high in bearing capacity, high in transmission efficiency, safe, reliable and long in service life.

The invention discloses a disease preventing insecticide natural mineral fertilizer and a preparation method and usage thereof. The fertilizer comprises following raw materials in parts by weight: 4-26 parts of potash feldspar, 3-15 parts of ultraphosphate, 20-66 parts of pumice, 20-45 parts of calcite, 18-33 parts of yellow liquid in stone, 6-10 parts of urea, 2-5 parts of celastrus angulatus, 2-5 parts of sanguinarine, 0.3-1.5 parts of adhesive, and 1-6 parts of stabilizer. The preparation method comprises the steps of smashing, mixing, smashing again, drying, cooling and canning. According to the usage, in 3-5 days after rain, the fertilizer is applied in the field twice a day in the morning and evening. The disease preventing insecticide natural mineral fertilizer for tropical plants not only has good preventing and curing effects and can prevent diseases of various types, but also is environment-friendly and can promote growing of crops effectively and solve the problems of the scholars and researchers in the field; the disease preventing insecticide natural mineral fertilizer has complete nutrition and high concentration, and is remarkable in fertilizer efficiency; plants using the fertilizer grow vigorously, and the yield and quality of crops using the fertilizer are significantly increased and improved.

The invention relates to a reachability-based airport group spatial layout optimization method, which comprises the following steps of: 1, carrying out regional grid division on a predetermined region; 2, randomly generating m feasible airport group layout strategies Pm based on a grid division result of the region A; 3, establishing an airport group space satisfaction model, and constructing an objective function Z according to airport distance satisfaction; 4, model calculation; 5, layout optimization iteration adjustment is carried out; and step 6, obtaining an airport group space layout strategy Pm and a global optimal solution Pg, and outputting and calculating the maximum airport group space satisfaction max Z. The airport group system structure and space distribution can be reasonably planned, the bottleneck of the overall service quality of the airport group is broken, the operation efficiency is improved, and support is provided for improving the service quality of the airport group system.