196results about How to "Guaranteed conversion efficiency" patented technology

The invention belongs to the field of genetic engineering of plants and discloses a method for building a high-efficiency regenerating and transforming system of Oryza sativaL. subsp. japonica 11 through cultivation of induction of embryogenic callus, subculture multiplication of embryogenic callus, transformation mediated by agrobacterium tumefaciens, cocultivation of embryogenic callus and agrobacterium tumefaciens, screening and cultivation of resistant callus and seedlings differentiation of resistant callus. The method has the advantages of simple technological processes, low production cost, and capabilities of obviously increasing the inductivity of the embryogenic callus, the subculture multiplication rate and the differentiation and regeneration rate of the embryogenic callus of the Oryza sativaL. subsp. japonica 11 and simultaneously shortening the period of obtaining regenerative rice plants; and on the basis, an improved agrobacterium tumefaciens-mediated method can be used for remarkably increasing the efficiency of obtaining the transgenosis rice plants and shortening the period of obtaining regenerative rice plants.

The invention discloses a polycrystalline silicon ingot casting molten material and an impurity removing process. The process comprises the following steps: 1, preheating: adopting an ingot furnace to preheat a silicon material filled in a crucible, and gradually raising the heating temperature of the ingot furnace to T1; the preheating time is 6-10h, and T1=1165-1185 DEG C; 2, melting: the melting temperature is T1-T5; T5=1540-1560 DEG C; in the melting process, filling insert gases into the ingot furnace, and keeping air pressure in the furnace in Q1, and Q1=550-650mbar; 3, removing impurities: the process is as follows: the 11th step, reducing pressure: the air pressure of the ingot furnace is reduced from Q1 to Q2, and the pressure reducing time is 8-12min, and Q2=350-450mbar; the 12th step, maintaining pressure; the 13th step, boosting pressure and lowering temperature. The process has the advantages of simple steps, reasonable design, convenience in realization, easiness in grasp and good using effect, can discharge gas containing carbon in the furnace in time, and increases the polycrystalline silicon ingot casting quality.

The invention discloses a working mode control method of a hybrid power vehicle. The method comprises the steps that usable driving power of a driving motor under a serial driving mode after the vehicle is started is obtained; whether or not a driver driving demanding power is met is judged according to the usable driving power of the driving motor; whether or not the engine can be allowed to enter an efficient area by the driver driving demanding power at a current driving speed when the engine is directly driven is judged; whether or not the demand in which the power of a whole vehicle is not reduced is met by the direct driving power of the engine at the current driving speed is judged; a working mode of the vehicle is switched to be a parallel driving mode. According to the method, theswitching timing of the working mode of the vehicle is decided to ensure that the power of the whole vehicle is not consumed and ensure the economical performance of the whole vehicle. The inventionfurther provides a working mode control device of the hybrid power vehicle and the hybrid power vehicle.

The invention discloses a melting process for polycrystalline silicon cast ingots. The process comprises the following steps: 1, preheating: an ingot furnace is adopted to preheat a silicon material filled in a crucible, and the heating temperature of the ingot furnace is gradually increased to T1; the preheating time is 6-10h, and T1=1165-1185 DEG C; 2 melting: the silicon material filled in the crucible is melted, the melting temperature is T1-T5, and T5=1540-1560 DEG C; after the silicon material in the crucible is completely melted, the heating temperature of the ingot furnace is controlled to T5, and then the heating power of the ingot furnace begins to decline; after the heating power of the ingot furnace stops declining and lasts for the time t, the melting process is complete; t=18-22min. The process has the advantages of simple steps, reasonable design, convenience in realization, easiness in grasp and good using effect and can effectively solve the problem that the quality of the produced polycrystalline silicon cast ingots is reduced as the melting time is deficient or too long.

The invention relates to a stainless steel heat exchanger with high heat exchange efficiency, energy conservation, environmental protection and free maintenance. The technical scheme provided by the invention is that: the stainless steel heat exchanger comprises a right tube plate, a left tube plate, radiating tubes and a shell, wherein two ends of the shell are provided with the right tube plate and the left tube plate with mounting holes; the radiating tubes are arranged in the shell; two ends of the radiating tubes are respectively inserted into corresponding holes of the right tube plate and the left tube plate; the radiating tubes comprise first radiating tubes and second radiating tubes; the interior of the shell is divided into three chambers, namely a combustion chamber at the bottom, a sparse tube chamber in the middle and a dense tube chamber on the top; the first radiating tubes are arranged inside the sparse tube chamber; the second radiating tubes are arranged in the dense tube chamber; the arrangement density of the second radiating tubes is greater than that of the first radiating tubes; and insulating plates are arranged between inner side walls of the left tube plate and the right tube plate and a contact surface of the shell. The stainless steel heat exchanger has the remarkable characteristics of high heat conversion efficiency, small floor area, space saving, application of stainless steel radiating tubes and free maintenance in 30 years.

The invention discloses a photovoltaic and photo-thermal combined system for full-spectrum solar energy frequency-division, regulation and control. The photovoltaic and photo-thermal combined system comprises an optical-focusing apparatus, a photovoltaic battery assembly and a frequency-division and heat-collecting apparatus, wherein the frequency-division and heat-collecting apparatus is arranged above the optical focus of the optical-focusing apparatus, the photovoltaic battery assembly is positioned on the optical-focusing apparatus and right below the frequency-division and heat-collecting apparatus, and the frequency-division and heat-collecting apparatus comprises a frequency division apparatus and a heat-collecting tube. Incident sunlight on the optical-focusing apparatus is reflected to and focused on the frequency-division and heat-collecting apparatus, the frequency division apparatus decomposes the sunlight into near infrared and ultraviolet light and visible light through frequency and division. The near infrared and ultraviolet light is directly transmitted to and absorbed by the heat-collecting tube from the frequency division apparatus, and converted into heat energy. The frequency division apparatus reflects the visible light to the photovoltaic battery assembly, which converts the visible light into electric energy. The photovoltaic and photo-thermal combined system makes full use of the full spectrum energy of sun light, and the energy conversion efficiency of the entire system is improved.

The invention relates to an aftertreatment system of before-turbine urea injection and a control method thereof. The aftertreatment system comprises a turbosuperchager, an SCRF system and an SCR system which are sequentially arranged on an engine exhaust pipeline, a first reducing agent nozzle is formed in an upstream pipeline of the turbosuperchager, a second reducing agent nozzle is arranged ona pipeline between the SCRF system and the SCR system, during cold starting or low-temperature condition, according to the aftertreatment system, the first reducing agent nozzle is arranged on the upstream portion of the turbosuperchager, the exhaust temperature before the turbosuperchager is used for achieving in-advance pyrolysis and hydrolysis of the urea, the SCRF system is subjected to ammonia storage and pretreatment, the NOX content in the tail gas can be reduced, in the high-temperature condition, the first reducing agent nozzle and the second reducing agent nozzle eject the reducing agent at the same time, the NOX conversion efficiency under the high temperature is ensured, the NOX content in the tail gas can be reduced, and the requirement of ultra-low emission regulations in thefuture can be met.

The invention discloses an IBC (Interdigitated back contact) battery, a battery pack and a preparation method, and relates to the technical field of solar cell. The battery comprises an N-type silicon chip, the backlight surface of the N-type silicon chip is divided into upper part and lower part, each part comprises a row and several columns P-type doped area, a N-type doped area is arranged between P-type doped areas or P-type doped areas and an edge of the silicon chip to form the P-type doped areas and the N-type doped area which are arranged in an alternatively adjacent way, each doped area of the upper part is connected with a corresponding doped area of the lower part through the same main grid line, each main grid line comprises a plurality of auxiliary grid lines which is used for connecting auxiliary grid areas on the doped areas. Under a premise of maintaining battery photoelectric conversion efficiency of the IBM battery, the pressure opening of the battery can be increase, the electric current can be reduced, and the power loss caused by a welding strip resistance during component packaging can be reduced.

The invention discloses antibiotic-free suckling pig artificial milk. Each kilogram of the suckling pig artificial milk is prepared from components according to the following use quantities: 400 to 600g of whole milk powder, 100 to 300g of whey protein concentrate, 70 to 150g of whey powder, 70 to 150g of lactose, 30 to 80g of fish meal, 1 to 30g of coconut oil, 0.8 to 1.5g of lysine hydrochloride, 3 to 10g of arginine monohydrochloride, 0.5 to 1.2g of DL-methionine, 0.3 to 0.7g of tryptophan, 5g of decavitamin and microelement premix and 1 to 5g of growth-promoting agent. The artificial milk sufficiently considers digestion physiology characteristics and nutriment requirements of newborn piglets in processing and selection of raw materials, sufficiently ensures feed conversion efficiency and palatability, can obviously control diarrhea of suckling pigs and improves food consumption and the immunity. The invention further discloses an antibiotic-free suckling pig liquid feed comprising the suckling pig artificial milk.

The invention discloses a laminating technique for a photovoltaic cell assembly. The laminating technique comprises the technical steps of placing an overlapped photovoltaic cell assembly on the working face of a laminating machine, closing the cover and laminating, and is characterized in that: the process of laminating technique comprises vacuumizing an upper chamber before the cover is closed, vacuumizing the lower camber after the cover is closed, raising the temperature in the lower chamber, charging air into the upper chamber for laminating, cooling working tabletop by charging air or water into the lower chamber, exhausting air in the upper chamber and solidifying in a drying oven; as the relationship between heating and cooling is determined in a laminating process, the air between the laminated layers of the photovoltaic cell assembly is exhausted before temperature rise and EVA melting to prevent air bubbles in a melting process; therefore, the quality of the photovoltaic cell assembly is improved, the rate of conversion of solar into electric energy of the photovoltaic cell assembly is guaranteed and the service life of photovoltaic panels is prolonged.

The invention discloses a barrel curved surface electromagnetic ultrasonic variable incident angle body wave weighted and combined imaging detection method and a barrel curved surface electromagneticultrasonic variable incident angle body wave weighted and combined imaging detection device. The barrel curved surface electromagnetic ultrasonic variable incident angle body wave weighted and combined imaging detection method comprises the steps of: introducing pulse current with the initial excitation frequency of f1 into an electromagnetic ultrasonic oblique incidence SV wave probe, and enabling the interior of a to-be-detected barrel to generate SV waves propagating along an incidence angle theta 1; receiving ultrasonic echoes and acquiring an A scanning signal by the electromagnetic ultrasonic oblique incidence SV wave probe; introducing pulse current with the excitation frequency fi=f1+deltaf*(i-1) into the electromagnetic ultrasonic oblique incidence SV wave probe in sequence, so that SV waves propagating along an incidence angle theta i are correspondingly generated in the to-be-measured barrel; and acquiring A scanning signals of the SV waves which are correspondingly generated by different excitation frequencies fi and propagated along the incident angle theta i, and performing weighted combination and coordinate correction to realize variable incident angle body wave weighted and combined B scanning imaging. By adjusting the excitation frequency, changing the incident angle of the oblique incident SV waves and carrying out weighted combination and coordinate correction on the obtained A scanning signals, B scanning imaging is realized, and the geometric information of the profile of a defect can be obtained.

A method and apparatus is provided for operating a methane-fuelled engine in a lean burn operating mode or a stoichiometric operating mode. When a methane oxidation catalyst is employed to treat the exhaust gas from an engine running in a lean burn operating mode, the catalyst can be inhibited by SOx reducing the catalyst's methane conversion efficiency. When an engine is running in a stoichiometric operating mode, desulphation of the catalyst can occur, thereby restoring the catalyst's methane conversion efficiency. The disclosed method relates to fuelling the engine with a lean fuel mixture when operating the engine at one of a predetermined first set of points on an engine map, and fuelling the engine with a rich fuel mixture when operating the engine at one of a predetermined second set of points on said engine map. The exhaust gas from the engine flows through a methane oxidation catalyst, which is preferred embodiments is adapted to promote the reduction of NOx when the engine is running in the stoichiometric operating mode. The apparatus comprises means for detecting and controlling lambda, and an electronic controller programmed to operate the engine in one of a lean burn mode and a fuel-rich mode at respective predetermined points on an engine map.

The invention discloses a preparation method of a cadmium-free buffer layer in a flexible CIGS thin film solar cell. The method is a chemical water-bath deposition method, and the prepared cadmium-free buffer layer is a zinc sulfide film. The method has the advantages of simple technology, large preparation area, low cost, simple equipment, no requirement of a vacuum system, low deposition temperature, and realization of growing polycrystalline or amorphous semiconductor films having a good stability and a high quality, . More importantly, there is no environmental pollution in the preparation process of zinc sulfide. The preparation method of the zinc sulfide film through chemical water-bath deposition comprises the following steps: 1, sequentially depositing a barrier layer, a back electrode layer and a CIGS absorption layer on a flexible substrate to form a sample; 2, preparing a reaction solution containing a zinc source, a sulfur source, a complexing agent and a buffer agent; 3, placing the sample in the reaction solution, and stirring and heating to prepare a film; and 4, drying a sample obtained in step 3 for later use.

The invention discloses a preparation method of 1,4,9(11)-triene-androst-3,17-dione, which uses a compound I 9alpha-OH-4AD as an initial raw material and comprises the following steps: A) elimination reaction: adding the compound I into an eliminating solvent to eliminate 9- alpha hydroxy group by using the eliminating reagent, and reacting to obtain a compound II; and B) fermentation conversion: preparing a fermentation culture medium by using the compound II as a raw material, inoculating a Nocard's bacillus strain into the fermentation culture medium, culturing for conversion, and extracting to obtain a compound III, namely 1,4,9(11)-triene-androst-3,17-dione. The new initial raw material adopted by the method is cheap and accessible; and the new elimination method avoids ultralow temperature reaction, is simple to operate, and has the advantages of low equipment investment, fewer side reactions and high yield.

The invention discloses an Agrobacterium local invasion device applied in a soybean hypocotyl explant transformation acceptor system, and an invasion method thereof. The invention provides the simply-designed device successfully applied in the Agrobacterium invasion of the soybean hypocotyl explant conversion acceptor system to inhibit the excess propagation of the Agrobacterium on the surface of the explant in a medium in order to prevent the decay of a plant material, and the device enables the whole explant to be immersed in the Agrobacterium solution, so only the upper end notches of the hypocotyl having an adventive bud regeneration potential undergo the Agrobacterium invasion. Invasion method conditions are further optimized in the invention. The medicine cost of the soybean hypocotyl explant genetic transformation acceptor system can be reduced and the transformation working efficiency can be improved through applying the device and the method.

The invention provides a direct current to direct current conversion circuit comprising a bridge circuit, a variable voltage circuit and a secondary rectifying circuit which are sequentially connected. In the secondary rectifying circuit, a positive electrode of a first rectifying unit and a negative electrode of a second rectifying unit are connected with one end of a secondary winding of the variable voltage circuit, a positive electrode of a third rectifying unit, a negative electrode of a fourth rectifying unit and the other end of the secondary winding are connected with one end of a controllable switch, one end of a first capacitor and one end of a second capacitor are connected with the other end of the controllable switch, the other end of the first capacitor is connected with the negative electrodes of the first rectifying unit and the third rectifying unit, and the other end of the second capacitor is connected with the positive electrodes of the second rectifying unit and the fourth rectifying unit. By the aid of the scheme, based on different scenes, off and on of the controllable switch are controlled, secondary rectifying modes are switched, assistant adjustment of output voltage is realized, and conversion efficiency is ensured in the scene that input and output voltage is changed within a wide range.

The invention discloses a snow-melting and deicing coating layer for a pavement and a preparation method of the snow-melting and deicing coating layer, and belongs to the technical field of functional coating layers. The snow-melting and deicing coating layer for the pavement is obtained by mixing components A, B and C, spraying the mixture to the pavement or coating the pavement with the mixture, and curing the mixture; the mass ratio of the components A, B and C is 100: (20 to 60): (70 to 150). The component A is prepared from epoxy resin, an elastic modifier, an epoxy active diluent, a snow melting agent and a dispersing agent; the component B is prepared from an epoxy curing agent, a curing promoter, a coupling agent and a pigment; the component C is prepared from quartz powder, magnet powder and crystal whiskers. The snow-melting and deicing coating layer realizes efficient snow melting and deicing under the synergistic action of the snow melting agent and microwave radiation heating. Compared with the prior art, the snow-melting and deicing coating layer for the pavement has the advantages of low energy consumption, convenience for construction and maintenance, low cost, low technical requirement, high snow melting and deicing efficiency, obvious environmental protection benefit and the like, and has a wide application prospect.

The invention discloses a method for polycrystalline silicon ingot casting. The method comprises a first step of installation of an auxiliary heater, wherein the auxiliary heater is installed in a polycrystalline silicon ingot furnace, the auxiliary heater is a bottom heater below a crucible, and the auxiliary heater forms a six-side heating device together with a top heater and four side heaters; a second step of charging; a third step of preheating; a fourth step of melting: six-side heating melting, fifth-side heating melting and follow-up melting; a fifth step of crystal growth; a sixth step of annealing and cooling which comprise primary annealing, secondary annealing and cooling, wherein during the primary annealing, the heating temperature of the polycrystalline silicon ingot furnace is reduced to T4 and heat insulation is performed for 2-3 h, and T4=1250-1280 DEG C; during the secondary annealing, the heating temperature of the polycrystalline silicon ingot furnace is reduced to T5 and heat insulation is performed for 2-3 h, and T5=900-950 DEG C. The method is simple in steps, reasonable in design, convenient to implement and good in using effect. The six-side heating device is adopted for heating, the oxygen content of the bottom of the crucible can be effectively reduced; the annealing process is adjusted, and the quality of a finished ingot can be effectively improved.

The invention belongs to the field of preparation of perovskite solar cells, and particularly relates to a method for efficiently and stably preparing a large-area perovskite solar cell based on porphyrin doping. The method is mainly characterized by comprises the following steps that firstly, a simple and convenient porphyrin and porphyrin derivative synthetic path is provided; secondly, a traceamount of porphyrin or a trace number of porphyrin derivatives are added into a perovskite pecursor solution; thirdly, a black and dense perovskite film is formed; and fourthly, a perovskite layer iscoated with the perovskite film containing the porphyrin and porphyrin derivative in a spinning mode, a hole transporting layer and an electrode layer are coated in sequence, and the perovskite solarcell is formed. The method has the beneficial effects that the perovskite film is doped with ammonium-based porphyrin, effective crystallization control over the perovskite film is achieved successfully, because the ammonium-based porphyrin has the properties of a surfactant, the film formation property of the solution is improved after the ammonium-based porphyrin is added into the solution, andthe pinhole-free and uniform large-area perovskite film is prepared through a scrape-coating process.

The embodiments of the invention disclose a vehicle fuel sulfur content monitoring method and device, equipment and a storage medium, and aims to ensure that the conversion efficiency of the nitrogenoxide of a vehicle after-treatment system is not influenced by the sulfur content of the newly added fuel. The method comprises the steps: when it is monitored that a new fuel is added into a vehicle,the fording duration of the vehicle between the last time of refueling and the current time of refueling is detected; when the fording duration is less than the preset maximum fording duration, the current nitrogen oxide conversion rate of the vehicle, the state of urea stored in a urea box, the temperature of a selective catalytic reducer and the temperature difference between an inlet of an oxidation catalyst and an outlet of the oxidation catalyst are detected; and according to the detected current nitrogen oxide conversion rate of the vehicle, the state of the urea stored in the urea box,the temperature of the selective catalytic reducer and the temperature difference between the inlet of the oxidation catalyst and the outlet of the oxidation catalyst, whether the sulfur content of the vehicle fuel exceeds the standard is determined.

The invention discloses a production process for a photovoltaic cell assembly. The production process is characterized by comprising the following steps of: testing a single bracket; welding the anode and cathode of a photovoltaic cell chip; overlapping; detecting a photovoltaic cell assembly; and laminating, curing and framing. In the production process, framing is performed along the top angle lines of the four corners of a frame, so that the framing time of a single piece is shortened, the connection is firm, the verticality of the periphery of the frame is high, great convenience is brought to the splicing of a photovoltaic cell matrix, and the working efficiency is increased by 70 percent. In a laminating process, bubbles are not generated in the melting process of EVA (Ethylene Vinyl Acetate), so that the quality of the photovoltaic cell assembly is improved, the efficiency of conversion of solar energy to electric energy is effectively ensured, and the service life of the photovoltaic cell assembly is prolonged.

The invention discloses an enhanced system and method for adsorption removal of mercury in coal-fired flue gas. The system comprises an additive feeding system and an adsorbent ejection system, wherein the additive feeding system is disposed on a coal feeding system, a boiler body, a denitration device or an air preheater, and the adsorbent ejection system is disposed between the air preheater and a dedusting device. The method includes: additives are added into the coal feeding system, the boiler body, the denitration device or the air preheater through the additive feeding system, and the additives are in complex physical and chemical reactions with zero-valence mercury in a boiler chamber or high-temperature flue system to convert the zero-valence mercury into bivalent mercury which is easier to be adsorbed by adsorbent; the adsorbent is ejected into a medium-and low-temperature flue gas system between the air preheater and the dedusting device to adsorb mercury and compounds thereof to generate mercury particles; finally, mercury is captured by the dedusting device along with the adsorbent and fly ash when flue gas passes through the dedusting device, thereby removal of mercury in coal-fired flue gas is realized.

The invention relates to the field of gardening crop genetic engineering, and provides an agrobacterium-mediated peach genetic transformation method. The method comprises the following steps: establishing a genetic transformation receptor, culturing agrobacterium, preparing an infection solution, conducting infection and co-culturing, conducting degerming, screening and culturing, and carrying out GUS staining identification on resistant calluses. According to the method, the calluses are used as receptors, GUS genes are used as reporter genes, genetic transformation of peaches is carried out with an agrobacterium GV3101 mediation method, the resistant calluses are obtained, and the resistant calluses are determined to be positive calluses through multiple times of subculture and GUS staining. According to the method, the success rate of agrobacterium-mediated transformation can be remarkably increased, and meanwhile, the method can be widely applied to peach genetic engineering, cell engineering, metabolic engineering and establishment of a peach genetic transformation system.

The invention discloses a cleaning method of texture surface making equipment for single crystal silicon, belonging to the technical field of solar battery preparation. The cleaning method comprises the steps: draining, water flushing, flakes removing, water flushing, wiping, water flushing, soaking and water flushing. The cleaning method of texture surface making equipment for single crystal silicon can increase the average conversion efficiency of a solar battery, prolong the maintenance period of equipment and increase the productive capacity of the equipment.

The invention discloses a method for melting of a polycrystalline silicon ingot casting based on auxiliary heating. The method comprises a first step of installation of an auxiliary heater, wherein the auxiliary heater is installed in a polycrystalline silicon ingot casting furnace, the auxiliary heater is a bottom heater arranged below a crucible, and the auxiliary heater, a top heater and four side heaters form a six-side heating device; a second step of charging; a third step of preheating, wherein the six-side heating device is started and the polycrystalline silicon ingot casting furnace is adopted to preheat a silicon material in the crucible; a fourth step of melting, and the process comprises the following steps: a step 401 of primary warming, a step 402 of secondary warming and a step 403 of follow-up melting. The method is simple in steps, reasonable in design, convenient to achieve, easy to master and good in use effect, and the problems of low melting efficiency, poor heating effects, high oxygen content of the bottom of a finished ingot casting as well as reduction of polycrystalline silicon ingot casting quality caused by melting time insufficiency or too long melting time and the like can be solved.

The invention discloses an oxidation catalyst for diesel engine exhaust. The catalyst adopts ceramic honeycomb cleaned by ultrasonic as a carrier. The catalyst is prepared by adding the ceramic honeycomb cleaned by ultrasonic into aged coating colloid, dipping and loading, drying the loaded ceramic honeycomb and calcinating. The catalyst can comprehensively treat discharge of carbon cigarette pellets and gaseous pollutants.

The invention belongs to the technical field of electronic equipment, and discloses a circuit for converting wide input voltage into high-power low output voltage. The circuit includes a 9-60V power input end, a DCDC power module, a circuit control unit, an MOS pipe and a board-grade DCDC chip, wherein the input end of the DCDC power module is connected to the 9-60V power input end, and the output end of the DCDC power module is connected to the board-grad DCDC chip; the input end of the circuit control unit is connected to the 9-60V power input end, the enabled output end of the circuit control unit is connected to the enabled pin of the DCDC power module, and the control output end of the circuit control unit is connected to the grid electrode of the MOS pipe; the source electrode of the MOS pipe is connected to the 9-60V power input end, and the drain electrode of the MOS pipe is connected to the board-grade DCDC chip. Meanwhile, the invention also discloses a method for converting the wide input voltage into the high-power low output voltage. The circuit and method can achieve the conversion from the wide input voltage to the high-power low output voltage, meet the demands for high-power equipment, and improve power supply efficiency.

The invention discloses an engine tail gas NOx purification system. The engine tail gas NOx purification system at least comprises a DOC, a first-stage SCR and a DPF which are sequentially arranged onan engine exhaust pipe in the tail gas flowing direction. A first-stage urea injection valve used for injecting urea to the first-stage SCR is arranged between the DOC and the first-stage SCR. The first-stage SCR is arranged between the DOC and the DPF, so that the problem that NOx in tail gas is too high in the cold start stage of an engine can be effectively solved, so that vehicle tail gas emission meets the requirement, and the purpose of protecting the environment is achieved. The invention further discloses the engine and a control method of the engine tail gas NOx purification system.

The invention discloses a modification method of adding an impervious layer to a flexible substrate in a flexible CIGS (Copper Indium Gallium Selenide) thin-film solar cell. Stainless steel is the preferred material for the flexible CIGS thin-film solar cell; however, diffusion of elements such as Fe and Cu in the substrate can cause reduction of the quality of the cell. Therefore, the seeking of an appropriate diffusion impervious layer material and a low-cost preparation process thereof is meaningful for improving device efficiency and reducing production cost. A 1-2 micron chromium diffusion impervious layer is deposited on a stainless steel substrate through a direct-current magnetron sputtering process; as a result, the crystallization quality of a back electrode layer and a CIGS absorption layer thin film both grown on the substrate can be obviously improved.

The present invention provides titanium tungsten powder and a preparation method thereof, wherein titanium dioxide powder with an anatase structure is modified with ammonium metatungstate to obtain the titanium tungsten powder. The titanium tungsten powder of the present invention can be used for preparation of the SCR catalyst for treating diesel engine waste gas NOx, wherein the anti-sulfur performance and the service life of the catalyst can be improved.