68results about How to "Improve electrical conversion efficiency" patented technology

A solar battery system with an improved effect of utilizing solar energy and a thermoelectric hybrid type solar battery system for furthermore recovering heat energy are provided. It is configured to include a solar battery panel 1 receiving sunlight at a light receiving surface 1a and supplying electricity generated by photoelectric conversion to the outside; a heat pipe 2 configured to have a serpentine thin hole provided therein with a sealed refrigerant fluid or configured to have a plate-shaped structure, for example, in a flat shape, a thin shape, furthermore, a thin film shape, wherein a surface of said plate-shaped structure on one end portion side is affixed to a back surface of said light receiving surface of said solar battery panel, and receiving heat H generated at said solar battery panel 1 from said one end portion 2a and conducting to the other end portion 2b; and a heat release part 3, such as a hot water generation part, receiving the heat from the other end portion 2b which is conducted in the heat pipe 2.

The invention discloses a hybrid power control method for a fuel cell vehicle. The hybrid power control method for the fuel cell vehicle comprises the following steps of setting an upper limit value and a lower limit value of an SOC of a power cell; obtaining an SOC value of the power cell, and controlling the turn-on and turn-off of a fuel cell according to the relationship between the SOC valueand the set upper limit value and lower limit value; when the fuel cell is in a working state, obtaining an expected power need of the fuel cell and an expected power need of the power cell; setting an actual output power of the fuel cell and an actual output power of the power cell according to the expected power need of the fuel cell, a power-efficiency curve of the fuel cell, and the expected power need of the power cell; and controlling the fuel cell and the power cell to jointly output energy to a drive motor and a vehicle load according to the set actual output powers. The hybrid power control method for the fuel cell vehicle is capable of effectively improving the total efficiency output of a hybrid power system with the fuel cell and the power cell, and increasing the hydrogen-electricity conversion efficiency.

The invention discloses a joint energy storage system and method with air and water as energy storage working media. The system comprises an air compression energy storage unit, an air expansion energy release unit, a water energy storage unit, a water energy release unit, an energy release logic judgment unit and a heat storage circulation loop. According to the system and method, based on optimal matching of an air and water joint containing cabin and a heat storage / heat exchange device, by means of the acting characteristic of compressible / incompressible fluid, pressure energy stored by high-pressure air is released in a staged manner for continuous power generation; a water turbine is preferentially utilized for release power generation, acting is achieved through an air expander after residual pressure air absorbs compression heat, and classification gradient efficient utilization of pressure energy and heat energy stored in the compression energy storage process is achieved; and compared with the traditional compression air energy storage technology, according to the system and method, the electric conversion efficiency of the energy storage system and the fast response capacity to power grid control are effectively improved, supplemental combustion and contamination are avoided, and an effective path of achieving clean, efficient and economical large-scale energy storage is achieved.

The invention relates to a graphene electrode dielectric elastomer driver. Graphene electrodes are arranged on the two side surfaces of the dielectric elastomer to form a sandwich structure, and a graphene electrode dielectric elastomer thickness displacement driver and a graphene electrode dielectric elastomer plane displacement driver are obtained by deformation in different directions; each graphene electrode comprises a graphene layer and an extraction electrode; the graphene layer is a graphene thin film, a graphene coating layer or a graphene composite material layer; and the graphene electrode dielectric elastomer driver is a graphene electrode single-layer dielectric elastomer driver, a graphene electrode stacked type dielectric elastomer driver, a graphene electrode tubular dielectric elastomer driver or a graphene electrode roll type dielectric elastomer driver. The graphene electrode dielectric elastomer driver can be widely applied to the fields of a robot, aerospace, a mechanical arm, a joint prosthesis, an automobile, artificial muscle, airship tail vane adjustment, a diaphragm pump, intelligent driving, biological medical treatment and the like.

The invention discloses a voltage-regulating variable-frequency hierarchical control ultrasonic plastic welding power supply, which comprises a sampling control unit, a rectifying and DC voltage-regulating unit, a fixed phase-shift angle inversion unit, a matching boosting isolating unit and an ultrasonic transducer. The sampling control unit comprises a microprocessor, a first signal conditioning circuit, a second signal conditioning circuit, a driving circuit, an effective value detection circuit and a phase detection circuit, wherein the first signal conditioning circuit and the driving circuit are connected with the microprocessor; the second signal conditioning circuit is respectively connected with the effective value detection circuit and the phase detection circuit; and the effective value detection circuit and the phase detection circuit are both connected with an AD sampling port of the microprocessor. The voltage-regulating variable-frequency hierarchical control ultrasonic plastic welding power supply has the advantages that output voltage and current waveform THD is small, the voltage-regulating range is wide, large-power ultrasonic welding can be realized, the voltage-regulating or power-regulating response is quick, the voltage ripple is small, the transducer has a small vibration amplitude fluctuation, the frequency tracking precision and the accuracy are high, the electric conversion efficiency is high and the like.

The invention discloses a coaxial heating chamber and an electronic cigarette device with the coaxial heating chamber. The electronic cigarette device with the coaxial heating chamber includes a coaxial heating chamber which is formed by the fact that an outer conductor chamber is regarded as a chamber, and an inner conductor column which is regarded as a column and inserts from one end of the outer conductor chamber into the outer conductor chamber; and a microwave source from one end of the inner conductor column inserted into the outer conductor chamber into the coaxial heating chamber to conduct microwave transmission to achieve the heating of microwave to a tobacco. A coaxial transmitter and the coaxial heating chamber are used, microwaves with the frequency of 915MHz and 2.45GHz canbe transmitted in the coaxial transmitter and the coaxial heating chamber, and therefore, a relatively mature solid-state microwave device can be used, especially 915MHz electrical conversion efficiency is higher; the size of the device can be effectively controlled; and due to the fact that the microwave has no temperature, through high frequency alternating electric field, polar molecules in thetobacco is made directly to move and heat, tobacco overall temperature is controlled in 200~300 DEG C, local high temperature does not exist, higher temperature does not exist in the overall coaxialheating chamber and the tobacco, cracking does not occur, and aldehyde or other harmful substances cannot be produced.

The invention relates to a plane structure perovskite solar cell and a preparation method thereof. The cell comprises a hole transport layer and a light capture layer, wherein the light capture layer is prepared from an MXZ3-type perovskite material; M is selected from Cs<+>, CH3NH3<+>, CH3CH2NH3<+>, CH(NH2)2<+> or a mixture thereof; X is selected from Pb<2+>, Sn<2+>, Ge<2+> or a mixture thereof; Z is selected from Cl<->, Br<->, I<-> or the mixture thereof; the hole transport layer is prepared from a doped or un-doped ADO2-type semiconductor material with a p-type delafossite structure; A is selected from Cu or Ag; D is selected from one or more of Cr, Ga, Sc, In, Y or Fe; and a doping element is selected from one or two of Mg, Ca, Sr or Ga. A film of the hole transport layer provided by the invention has good electrical conductivity, proper energy level position, high transmittance and low cost; a solar cell device with excellent and stable performance can be obtained; and propulsion of industrialization of the perovskite solar cell is facilitated.

The invention relates to a non-contact transmission friction-electromagnetic composite wave energy collector adapted to complex excitation. The device collector comprises a floating ball, a rocker, alifting rod and a frequency-increasing electromagnetic power generation assembly, the floating ball is rigidly connected with the top of the rocker; the bottom end of the rocker is connected with thelifting rod through a universal joint; an electret rolling ball capable of rolling is arranged in the floating ball; a metal pole I and a metal pole II are arranged on the lower surface in the floating ball; the lifting rod is arranged in a lifting sleeve; a spring is arranged between the lifting rod and the lifting sleeve; a driving permanent magnet combination is arranged on the lifting rod; thelower end of the lifting sleeve is connected with a frequency-increasing electromagnetic power generation assembly, the frequency-increasing electromagnetic power generation assembly is provided witha driven permanent magnet combination, the driving permanent magnet combination is in magnetic coupling connection with the driven permanent magnet combination, the driven permanent magnet combination is in mechanical transmission connection with a power generation permanent magnet, and the power generation permanent magnet is correspondingly provided with a power generation induction coil. The collector can effectively work in a marine all-weather climate environment, adapts to complex wave excitation, and has a frequency increasing function and high reliability.

The invention provides a thermoelectric generator using superconducting fluid for heat transfer, and belongs to the field of development and utilization of new energy techniques. The thermoelectric generator using superconducting fluid for heat transfer is characterized in that hot fluid flow into a hot fluid inlet pipe (1), is diverted to enter branch pipes and then is diverted to enter a hot fluid heat exchanger module (5a), in the hot fluid heat exchanger module (5a), heat is transferred to the two planes of the hot heat exchanger module (5a) through the superconducting fluid, semiconductor thermoelectric generating sheets are placed in parallel or in series on the planes to form high-temperature end surfaces, the heat of the high-temperature end surfaces is transferred to low-temperature end surfaces through the thermoelectric generating sheets, and the low-temperature end surfaces are in contact with cold ends for heat dissipation; the hot fluid which flows through the hot fluid heat exchanger module (5a) flows out of a hot fluid outlet pipe (2); cold fluid flows into a cold fluid inlet pipe (3) and flows out of a cold fluid outlet pipe (4) to form the cold ends on the surfaces of a cold fluid heat exchanger module (5b); and the semiconductor thermoelectric generating sheets (9) and the cold and hot end surfaces of the heat exchanger module (5) are alternately arranged to generate temperature difference to generate power. The invention provides a method for generating power in a large scale by using steam, flue gas, industrial waste gas, terrestrial heat, solar energy and the like. The method is not only energy-saving, but also environmental-friendly.

The invention provides a superconducting claw-pole motor. A stator part comprises a hollow support shaft, n superconducting exciting winding supports and a Dewar structure, wherein the n superconducting exciting winding supports and the Dewar structure are fixed on the hollow support shaft, a superconducting exciting winding is arranged in each exciting winding support, and a refrigerant pipe and a superconducting outgoing line are arranged in the hollow support shaft; a rotor part comprises a rotor shaft and n rotor magnet yoke sets; and each rotor magnet yoke set comprises an A magnet yoke and a B magnet yoke, claw poles on the two magnet yokes are distributed in a staggered mode and oppositely buckled on the two sides of a corresponding superconducting exciting winding, and the rotor shaft and the n rotor magnet yoke sets can rotate synchronously around the central axis of the rotor shaft. Motors in different power levels can be implemented through expanding the diameters along the radial direction or increasing the number of superposed claw pole assemblies along the axial direction. According to the invention, under the premise of meeting the operation of superconducting motors, the superconducting claw-pole motor disclosed by the invention has the characteristics of simple structure, low cost, easy machining, direct power-supply connection of exciting windings, no carbon brush or induced circuit required, small weight and size, and the like, and improves the reliability and efficiency of systems.

The invention relates to a high energy solid state discharge igniting module, a inverter component is composed of a PWM control chip U1 which enables electric connection between a filter circuit and a boosting transformer and its auxiliary circuit, the boosting transformer is electrically connected to an energy-storage capacitor component through a high voltage silicon stack D1, a discharge control component is electrically connected to a part between the energy-storage capacitor component and a high voltage boost circuit, the high voltage boost circuit is composed of a high-frequency transformer electrically connected to a mutual inductance coil L1 and an oscillation capacitance C8, a dc source DC is electrically connected to the filter through a power supply input interface for completing the filtering, and converted to high voltage AC pulse through an inversion circuit and the boosting transformer, and is charged through the silicon stack rectification backward energy-storage capacitor component, and high voltage is output to a high voltage output interface can be completed by the discharge control circuit and the high voltage boost circuit. The high energy solid state discharge igniting module has the advantages of high loss of gas discharge tube energy, low transition efficiency and short life, and the output energy and transition efficiency can be increased by about 30%. The high energy solid state discharge igniting module has the characteristics of high efficiency, long life and no radioactivity.

The invention provides a method for regulating the wavelength of light emitted by an LED, which comprises the following steps: firstly, growing a first n-shaped ohm contact layer on a buffering layer; then depositing a layer of SiO2 films as mask films; disposing a growing window with a certain geometrical shape and size on the mask films; and then continuously growing a second n-shaped ohm contact layer, an active layer and a p-shaped ohm contact layer at the growing window. An instrument which is prepared under the same growing process condition emit radiation light with different wave bands in such a way that growing windows with different shapes and sizes regulate the inside stress of a secondary epitaxial instrument. By adopting the special method, a white light LED can be prepared, i.e. the growing windows with different shapes, sizes and amounts are designed at different areas of the mask films according to a preset design, and the white light is obtained through mixing radiation lights which can be emitted from different wave bands of one instrument. The LED instrument can emit the white light by only one chip and has the advantages of simple and convenient preparation, simple circuit, no need of fluorescence, long service life and higher photoelectric transformation efficiency.

The invention discloses a durable photovoltaic component, which comprises an upper cover plate, an EVA (Ethylene Vinyl-Acetate) adhesive film, a monocrystalline silicone battery component string, a backboard, a frame and a junction box, wherein the upper cover plate, the EVA adhesive film, the monocrystalline silicon battery component string and the backboard are laminated into a component by a laminating machine after being sequentially stacked from top to bottom, then the junction box is adhered to the back surface of the component, and the frame is finally mounted on the component; the upper cover plate is tempered glass of which the surface is coated with a nanometer titanium dioxide coating. Through the adoption of the scheme, the photovoltaic component is high in photoelectric conversion efficiency, and meanwhile, the service life can reach more than 25 years.

The invention provides a magnetic shielding structure applied to an ultrahigh voltage autotransformer clamp and relates to the magnetic shielding structure. The magnetic flux leakage density between an inner winding and an outer winding of the ultrahigh voltage autotransformer is high; and the loss cannot be effectively reduced and the hidden danger of local overheating cannot be effectively eliminated by use of a usual method. The magnetic shielding structure comprises a bent magnetic shielding part, a first insulating base plate and a fastener of connecting the bent magnetic shielding part and the first insulating base plate to the clamp; the cross section of the bent magnetic shielding part is L-shaped and the bent part is in circular arc transition; and the bent magnetic shielding part is arranged at the outer end part of the clamp. The L-shaped bent magnetic shielding part is added to the outer end part of the clamp with relatively high leakage flux density, so that leakage flux entering a non-magnetic clamp is reduced and the additional loss generated by the leakage flux can be effectively reduced.

The invention discloses a frequency-stable solid state discharging ignition device which is connected with a power input port. The frequency-stable solid state discharging ignition device comprises aninverter circuit, a spark frequency stabilizing circuit, a booster circuit, a rectifying circuit, an energy storage circuit, a discharging circuit and a high-frequency booster circuit; the inverter circuit, the booster circuit, the rectifying circuit, the energy storage circuit, the discharging circuit and the high-frequency booster circuit are connected with each other in turn; an output end ofthe energy storage circuit is connected with an input end of the spark frequency stabilizing circuit; the output end of the spark frequency stabilizing circuit is respectively connected with the inverter circuit and the discharging circuit. The frequency-stable solid state discharging ignition device is capable of solving the problems of high energy loss, uncontrollable discharge time and short service life of the traditional ignition device and has the characteristics of high efficiency, long service life and high spark frequency stability.

A resonant transformer includes a bobbin, a primary winding coil, plural secondary winding coils, and a magnetic core assembly. The bobbin includes a main body and a channel running through the main body. The main body includes a first winding section and plural single-trough second winding sections. Plural pins are arranged at the first winding section. The single-trough second winding sections are arranged at bilateral sides of the first winding section. The primary winding coil is wound around the first winding section of the bobbin and connected with the pins. The secondary winding coils are wound around respective single-trough second winding sections of the bobbin. The magnetic core assembly is partially embedded into the channel of the bobbin.

The invention discloses a photovoltaic cell with three layers of antireflective films in composite structures and a composite coating method thereof. Three layers of silicon nitride antireflective films in composites structures are coated on the surface of a silicon chip of the photovoltaic cell from inside to outside, thicknesses and refractive indexes are 10nm, 2.3; 22nm, 2.16; and 50nm, 2.0 respectively. Through refraction synthesis of composite film layers, the absorption bandwidth of the silicon chip to sunshine of each frequency spectrum band is expanded, reflection is reduced maximally to improve the photoelectric conversion efficiency of the photovoltaic cell, the defects that the antireflection spectral bandwidth is narrow and the photoelectric conversion efficiency is difficult to improve in the prior art are overcome, the antireflection spectral bandwidth is expanded and the photoelectric conversion efficiency is improved through the three layers of the silicon nitride antireflective films in composites structures.

The invention provides a friction nanometer and electromagnetic power generation composite wave energy conversion device which comprises a central tube, permanent magnet assemblies, a coil assembly and an oscillating body. The permanent magnet assemblies are arranged at the two ends of the central tube, the electromagnetic induction coil assemblies are arranged at annular grooves of two substrates of the central tube respectively, a first metal plate and a second metal plate are arranged on the inner wall face of the central tube, an organic film is deposited on the outer edge face of the oscillating body and the oscillating body suspends in the central tube due to magnetic repulsive force. According to the invention, low-frequency energy in waves is converted into electric energy by ingeniously utilizing friction motion between a metal plate and an organic material in the device and magnetic induction line cutting motion of a coil. The device can effectively work in an ocean all-weather climatic environment, effectively utilizes wave energy with complex frequency, and has the advantages of simple structure, low maintenance cost and high reliability.

A method for processing an electronic component using a supercritical fluid includes introducing the supercritical fluid into a cavity. The supercritical fluid is doped with a hydrogen isotope-labeled compound, an organic metal compound, an element selecting from a halogen element, oxygen, sulfur, selenium, phosphorus or arsenic, or a compound containing the element. An electronic component in the cavity is modified by the supercritical fluid at a temperature above a critical temperature of the supercritical fluid and a pressure above a critical pressure of the supercritical fluid.

The invention relates to a solar direct current (DC) lamp circuit, relating to a circuit structure and comprising a solar driving circuit (A), a circuit-driving network (B), a voltage-dividing clamping circuit (C) and a lamp circuit structure (D). The circuit-driving network (B) is used for a pulse generator to generate pulses; in the voltage-dividing clamping circuit (C), a divider resistor forms negative feedback to the driving circuit (A), a stabilivolt tube divides the voltage of a driving signal, clamps the peaks of the driving signal and restrains driving voltages in a starting moment and a high-voltage input moment; and the lamp circuit structure (D) comprises a lamp, a start capacitor and a transformer (T) and is connected in parallel with the voltage-dividing clamping circuit (C). The invention solves the problems of the traditional DC lamp circuit structure, such as great loss, low efficiency, short service life of switches and security risk.

A method for reducing defects of an electronic component using a supercritical fluid includes recrystallizing and rearranging grains in the electronic component by introducing the supercritical fluid doped with H2S together with an electromagnetic wave into a cavity. The cavity has a temperature above a critical temperature of the supercritical fluid and a pressure above a critical pressure of the supercritical fluid.

A low cost design for a concentrated photovoltaic (CPV) solar cell device is developed with a 3-D solar cell structure that eliminates the need for sun-ray tracking and with improved electricity conversion efficiency for cooling solar cells. The 3-D solar cell structure can be built with conventional monocrystalline or polycrystalline silicon or with multi-junction III-V solar material, joining two or more solar cell segments perpendicular to a base solar cell. This structure is able to collect all incident sunlight from sunrise to sunset.

The invention discloses a transformation method of lactobacillus brevis, and belongs to the technical field of food microorganisms. Since biochemical characteristics, molecular constitutions and immunological characteristics of bacterial strains of different species of lactic acid bacteria are all different, improvement is made on the basis of an existing electrotransformation method for lactococcus lactis and lactobacillus brevis which does not contain endogenous plasmids. The lactobacillus brevis is continuously activated twice separately through an MRS culture medium and an MRS culture medium containing 1% glycine, and continues to be cultured until the thalli reach a high concentration, then the lactobacillus brevis is collected, competent cells are prepared, and the concentration andactivity of the competent cells are improved accordingly. When exogenous DNA fragments are subjected to electrotransformation, the electric shock condition is 2.4 KV and 3.5 ms, and the electrotransformation efficiency is improved. As is checked, the competent cells are successfully transformed through exogenous genes, and the problems of preparation and transformation in the process of electrotransformation of wild lactobacillus brevis into the competent cells are solved.

The invention relates to an instant type electric heating tap which comprises a heating tube and a control panel. An electric heating film layer is coated on an inner surface of the heating tube, and electric heating film connecting electrodes are disposed on the mouth of the heating tube. An insulation strip winding the heating tube for a loop is disposed at the lower end of the electric heating film connecting electrodes, the distance between the insulation strip and the connecting electrodes is 1-2cm, and a conductive bar is disposed between the heating film and the connecting electrodes. The electric heating film connecting electrodes are the same, without positive electrode and negative electrode, both alternative current and direct current can be connected with the connecting electrodes, and voltage is within the range of 300-400v. A part of the electric heating film which is coated on the heating tube emits heat, and thus electric electrodes are connected to the heating tube safely and reliably. The heating film has the advantages that connection is firm, service life is long, a heating face is an infrared face, heat transmission is concentrated, and electric conversion efficiency is high. Further, electric heating conversion rate of the electric heating tap made of the heating film is as high as 95%, power is 1-4kw, the electric heating tap can provides hot water of 30 DEG C or so after powered on for a few seconds, and a user can use the water to wash hands or clothes. The instant type electric heating tap is energy-efficiency and energy-saving, and overall operating cost of the instant electric heating tap is lower than the prior electric heating taps.

The invention discloses a heat power type solar air conditioner which is characterized by comprising a solar thermal collector, an expansion machine system and a refrigerant circulation system. The expansion machine system comprises a first generator and a second generator, the solar thermal collector is in heat exchange connection with the first generator of the expansion machine system, and the refrigerant circulation system is in heat exchange connection with the second generator of the expansion machine system. The heat power type solar air conditioner is reasonable in structural design, can effectively low-grade heat generated by solar energy to convert and use mechanical energy and can effectively use low-grade hot water generated by the solar thermal collector to drive the expansion machine system to convert mechanical energy through heat exchange. The refrigerant circulation system is driven by the mechanical energy to meet requirements of a refrigeration air conditioner. The heat power type solar air conditioner is high in solar electric conversion efficiency and low in conversion cost and facilitates industrial application.

The invention provides an iPS cell as well as a reprogramming method and application thereof. The reprogramming method comprises the following steps that (1) urine is collected, centrifuging is carried out, a supernate is discarded, precipitates are washed, and cells are resuspended; (2) a coated culture dish is inoculated with the resuspended cells obtained in step (1), culture is carried out overnight, then liquid is changed for culture until UDCs (urine-derived cells) clones grow out, and subculture is carried out; and (3) a culture medium for subculture is sucked and discarded, trypsinization is carried out, the cells are collected and counted, plasmids are subjected to transfection by using an electric transfection method and are added into a resuscitation culture plate for culture overnight, and then liquid is changed for culture, and iPS clones are screened, wherein the plasmids comprise pCXLE-hOCT3 / 4-shp53, pCXLE-hSK and pCXLE-hUL. The method has the advantages that materials are convenient to obtain, trauma and ethical problems are avoided, the safety is remarkably improved, and meanwhile the whole reprogramming cost is lowered.

There is provided a fuel cell system. The fuel cell system includes a fuel cell generating electricity and heat by an electrochemical reaction between a fuel and air, a thermoelectric element converting heat, emitted from the fuel cell, into electrical energy, and a heat storage tank storing heat emitted from the thermoelectric element. The fuel cell system includes therein a configuration allowing for the conversion of heat, emitted from a fuel cell, into electricity or the utilization of heat, thereby minimizing the amount of heat that is released at the final stage. Therefore, a reduction in the size of a heat storage tank can be achieved, and the electricity conversion efficiency of a fuel cell can be improved.

The invention discloses a method for electroporation of Staphylococcus carnosus. The method comprises the following three steps: preparation of competent cells, electroporation, and resuscitation and culture. In the step of preparation of competent cells, Staphylococcus carnosus ATCC 51365 is activated in a LB medium and then inoculated into a growth medium B2, then undergoes shaking culture until OD578 is 0.6, and then is washed with a GS electric shock buffer. In the step of electroporation, to be transformed plasmids and the competent cells are uniformly mixed and subjected to ice-bath treatment and electroporation. In the step of resuscitation and culture, 1 mL of a LBM resuscitation medium is rapidly added into an electric shock cup after electric shock, the plasmids and the competent cells are taken out after uniform mixing and subjected to resuscitation and culture for 4 h, and the plasmids and the competent cells then coat a plate for culture overnight so as to obtain recombinant Staphylococcus carnosus with the introduced plasmids. With the method provided by the invention, conversion efficiency reaches 5.95 * 10<3> CFU / [mu]g DNA, so the conversion efficiency of Staphylococcus carnosus is greatly improved.

A low cost design for a concentrated photovoltaic (CPV) solar cell device is developed with a 3-D solar cell structure that eliminates the need for sun-ray tracking and with improved electricity conversion efficiency for cooling solar cells. The 3-D solar cell structure can be built with conventional monocrystalline or polycrystalline silicon or with multi-junction III-V solar material, joining two or more solar cell segments perpendicular to a base solar cell. This structure is able to collect all incident sunlight from sunrise to sunset.

The invention provides a preparation and transformation method of streptococcus thermophilus competent cells. The preparation and transformation method of the streptococcus thermophilus competent cells comprises the following steps: cultivating the streptococcus thermophilus in an LM17 culture medium until OD600 is 0.3 to 0.9, mixing the LM17 culture medium and an SLM17 culture medium according tothe ratio of 1:1, performing incubation at 37 DEG C for 1 hour, centrifugally connecting thallus at 4 DEG C, washing cells with a precooled buffer solution to obtain competent cells, mixing the competent cells and pIB184 plasmid uniformly, performing electric shock by using electric field intensity of 12.5 kV / cm, and performing resuscitation in an LM17MC2 culture medium for 3 to 8 hours to obtainthe highest electric transformation efficiency, which is 1.3*106 CFU / ug DNA, of the streptococcus thermophilus. The method provided by the invention is simple in operation and high in transformationefficiency; and a new technical method is provided for genetic modification of the streptococcus thermophilus and molecular mechanism for illuminating phenotypic characteristic.