72results about How to "Increase growth temperature" patented technology

The invention relates to the technical field of flower cultivation, in particular to a method for cultivating peonies for oil. The method comprises the steps that sandy soil is laid in a greenhouse, pH is adjusted, and fertilization and sterilization are carried out; selected peony plants for the oil are planted with row spacing*line spacing of 30cm*50cm; hoeing and topdressing are carried out in the growing period of the peonies for the oil, indoor air ventilation and light transmission are kept, insect killing and sterilization are carried out, chlormequat chloride is sprayed, the flower head of each plant is covered with a plastic bag for 2-3 days, and then a plurality of small holes are pricked in each plastic bag with needles; in the florescence, the plastic bags on the flower heads of the plants are removed, gibberellins and daminozide are sprayed on pistils and stamens respectively, pollinating insects are placed in the greenhouse, temperature, illumination time and ventilation time in the greenhouse are controlled, and meanwhile hand pollination is carried out; fallen leaves are swept away in time, and are burned up or buried deeply in a centralized mode. According to the method, the growing conditions of the peonies for the oil are improved, meanwhile, the pollination success rate in the florescence of the peonies for the oil is increased, and therefore the seed setting rate is improved.

A method of making II-VI core-shell semiconductor nanowires includes providing a support; depositing a layer including metal alloy nanoparticles on the support; and heating the support and growing II-VI core semiconductor nanowires where the metal alloy nanoparticles act as catalysts and selectively cause localized growth of the core nanowires. The method further includes modifying the growth conditions and shelling the core nanowires to form II-VI core-shell semiconductor nanowires.

The invention discloses a preparation method for an epitaxial wafer of a GaN-based light emitting diode, and belongs to the technical field of a semiconductor. The preparation method comprises the steps of laminating a buffer layer, a non-doped GaN layer, an N type layer, a stress release layer, a multi-quantum well layer and a P type layer on a sapphire substrate in sequence, wherein the stress release layer comprises multiple stress release sub-layers, the stress release sub-layers comprise a first sub-layer, a second sub-layer, a third sub-layer and a fourth sub-layer which are laminated in sequence, the first sub-layer is an AIGaN layer, the third sub-layer is an InGaN layer, the second and fourth sub-layers are GaN layers, and the growth temperature of the first sub-layer is higher than that of the third sub-layer. According to the method, a periodic structure is employed in the stress release layer, the relatively low growth temperature is employed in the InGaN layer, thereby facilitating good growth of lattices, the stress generated between the sapphire substrate and the GaN layers due to lattice mismatch can be released, the growth quality of the multi-quantum well layer is improved, and the photoelectric property of the LED is improved.

The ternary alloy CdSe_xTe_1-x(2 1 1) and the quaternary alloy Cd_1-zZn_zSe_xTe_1-x have been grown on Si(2 1 1) substrates using molecular beam epitaxy (MBE). The growth of CdSeTe is facilitated using a compound CdTe effusion source and a Se effusion source while the growth of CdZnSeTe is facilitated using a compound CdTe effusion source, a compound ZnTe effusion source, and an elemental Se source. The alloy compositions (x) and (z) of CdSe_xTe_1-x ternary compound and Cd_1-zZn_zSe_xTe_1-x are controlled through the Se/CdTe and ZnTe/CdTe flux ratios. The rate of Se incorporation is higher than the rate of Te incorporation as growth temperature increases. As-grown CdSeTe with 4% Se and CdZnSeTe with 4% Zn+Se, which is substantially lattice matched to long-wavelength infrared HgCdTe materials, exhibits excellent surface morphology, low surface defect density (less than 500 cm²), and a narrow X-ray rocking curve (a full-width at half maximum of 103 arcsec).

The invention discloses a culture method for chlorella, which comprises the following contents: the volume of chlorella seed liquid in a bioreactor accounts for 5 to 15 percent of the total volume of a culture medium; a gas containing 5 to 15 volume percent of CO2 is introduced, the volume of introduced gas is 0.1 to 1.0vvm; and the culture temperature is reduced to 0 to 15 DEG C from 25 to 40 DEG C within 0.5 to 10 days, and chlorella is continuously cultured at a constant temperature of 0 to 15 DEG C for 5 to 15 days. The method disclosed by the invention can allow microalgae to grow normally at a low temperature, and the accumulated amount of fat and CO2 utilization rate of microalgae can be increased.

The invention discloses an epitaxial wafer of a light-emitting diode and a growth method thereof, and belongs to the technical field of semiconductors. The epitaxial wafer comprises a substrate, and a buffer layer, a non-doped GaN layer, an N-type GaN layer, a light-emitting layer and a P-type GaN layer which are laminated on the substrate in turn. Mg is doped in the buffer layer. According to the epitaxial wafer, Mg is doped in the buffer layer, Mg can induce the material of the buffer layer to three-dimensional growth from two-dimensional growth to form three-dimensional island crystal grains with no requirement for the growth mode of low temperature and low pressure of the buffer layer, and the growth temperature of the buffer layer can be increased so that edge dislocation, screw dislocation and other lattice defects can be reduced, the crystal quality of the epitaxial wafer can be enhanced and the internal quantum efficiency and the anti-static capacity of the LED can be enhanced. Besides, the non-doped GaN layer is arranged between the buffer layer and the N-type GaN layer, and the non-doped GaN layer has the effect of separation so as to avoid the influence of the doped Mg in the buffer layer on electron injection light-emitting layer composite luminescence of the N-type GaN layer.

The invention provides an AlN single crystal substrate production apparatus and an application method thereof. The main body of the AlN single crystal substrate production apparatus is a high temperature resistant crucible and the crucible is divided into two parts, namely a crystal growth chamber and a raw material chamber. A gas pipe of ammonia gas or nitrogen gas or mixed ammonia gas and nitrogen gas is arranged on the sidewall of the crystal growth chamber, and a gas outlet is formed in a position opposite to the gas pipe; a substrate is fixed on the top of the reaction chamber; a carrier gas pipe is arranged at the bottom of the raw material chamber; raw materials are placed at the bottom of the raw material chamber; and the growth chamber is separated from the raw material chamber by a perforated separator. The crucible can be heated by heaters around the crucible, or directly heated by use of the crucible. According to the AlN single crystal substrate production apparatus, a large-size cheap sapphire substrate is taken as seed crystal for AlN crystal growth and the problem of expensive seed crystal of the PVT apparatus is solved; and besides, compared with halide vapor phase epitaxy (HVPE) equipment, the growth temperature of the AlN single crystal substrate production apparatus is higher and closer to the balance growth temperature of the AlN crystal, and therefore, the grown crystal is higher in quality.

The invention provides a preparation method of an ultraviolet LED and the ultraviolet LED. The preparation method comprises the following steps: introducing a metal source and a V-group reactant on a substrate, and decomposing to form a buffer layer under high temperature; increasing growth temperature, growing a non-doped AltGa1-tN layer and growing an N-type AluGa1-uN layer on the basis of the AltGa1-tN layer; adjusting the temperature to be a temperature for growing quantum wells, and growing an AlxGa1-xN/AlyGa1-yN multi-quantum well structure; growing an AlzGa1-zN electron barrier layer with the thickness of 5 to 100 nm on the grown AlxGa1-xN/AlyGa1-yN multi-quantum well structure; growing a P-type layer with high hole concentration and low ultraviolet absorption rate on the basis of the AlzGa1-zN electron barrier layer, wherein the P-type layer is an AlvGa1-vN/GaN superlattice structure, a P-type GaN layer with high dosage concentration is on the P-type layer to form a P-type ohmic contact layer. Through the embodiment of the invention, the absorption of the P-type layer for ultraviolet light emitted by the quantum wells can be effectively reduced, the luminous efficiency of the ultraviolet LED is improved, and the service life of the ultraviolet LED device can be prolonged.

The new fluorocarbon-functionalized and/or heterocycle-modified polythiophenes, in particular, α,ω-diperfluorohexylsexithiophene DFH-6T can be straightforwardly prepared in high yield and purity. Introduction of such modifications to a thiophene core affords enhanced thermal stability and volatility, and increased electron affinity versus the unmodified compositions of the prior art. Evaporated films behave as n-type semiconductors, and can be used to fabricate thin film transistors with FET mobilities ˜0.01 cm²/Vs—some of the highest reported to date for n-type organic semiconductors.

The invention discloses a GaN-based light emitting diode epitaxial wafer and a manufacturing method therefor and belongs to the field of light emitting diodes. The GaN-based light emitting diode epitaxial wafer comprises a substrate, a buffer layer, a three-dimensional growth layer, a u-GaN layer, an n type layer, an n type current expansion layer, a stress releasing layer, a multiple quantum well layer and a p type layer; wherein the buffer layer, the three-dimensional growth layer, the u-GaN layer, the n type layer, the n type current expansion layer, the stress releasing layer, the multiple quantum well layer and the p type layer orderly arranged on the substrate in a covering manner; the n type current expansion layer comprises a first sub-layer covering the n type layer and a second sub-layer covering the first sub-layer; the first sub-layer is an AlGaN layer, the second sub-layer is of a superlattice structure formed by a non-Si-doped GaN layer and an Si-doped GaN layer, the first sub-layer is higher than the n type layer and the second sub-layer in terms of growth temperature, and the second sub-layer is greater than the first sub-layer in terms of growth pressure. The GaN-based light emitting diode epitaxial wafer is capable of overcoming defects and improving photoelectric performance.

A polymorphous Hanson yeast expressed recombinant cholera toxin B subunit gene (CTB) is disclosed. In order to increase the expression of CTB in Hanson yeast, the coding gene of CTB is redesigned according to the application method of codon for the high-expression gene of Hanson yeast. The expression product can be used for preventing the diarrhea caused by cholera ribro and as the immune vaccine.

The invention belongs to a method for surface modification of a ceramic valve core, and particularly relates to a method for preparing an ultra nanometer diamond coating, which can improve the overall performance of a ceramic valve core matrix. The method comprises the following steps of: soaking the planar tap ceramic valve core in soaking solution; grinding the surface of the matrix by using diamond micropower suspension; and placing the ceramic valve core in a microwave plasma reaction cavity for growing the ultra nanometer diamond coating. The ultra nanometer diamond coating generated by the method has the advantages of high wear resistance and hardness, small frictional coefficient and thermal expansion coefficient, high self-lubrication, high chemical stability, no toxin and harmlessness and high hydrophobicity; and the ultra nanometer diamond coating can also improve the overall performance of the tap using the ceramic valve core, and the service life of the tap is prolonged by over 10 times. The tap and the oil-gas valve can be used in various mediums for a long time, are always kept tightly sealed and eliminate leakage, and are switched flexibly and light.

The invention discloses a preparation method of an epitaxial wafer for an 8-inch high-power IGBT component. The method includes following steps: preparing a substrate: selecting an 8-inch substrate with a p-doped middle resistance, wherein the resistivity is 3-25 ohm*cm, and a back-sealing structure is in a polycrystalline (Poly) back-sealing mode; HCl polishing: selecting the HCl flow of 1-2 L/min at the temperature lower than 1080 DEG C with the polishing time of 2 minutes, and performing purging with high-flow H2 for 3 minutes after completion of polishing; and epitaxial growth: selecting at least three layers of epitaxial process conditions, wherein a silicon source employs ultra-high-purity trichlorosilane, the epitaxial growth of each layer employs the same growth temperature and growth rate, an epitaxial layer with flat resistivity is grown on a first layer, an intermediate transition layer is grown on an intermediate layer through introduction of a doping source with a variabledoping flow, and a high-resistance epitaxial layer is grown on a final layer. According to the method, the growth of the epitaxial layer of each layer employs the same growth rate and growth temperature so that the controllability of epitaxial parameters of products in a batch production process is facilitated.

An object of the present invention is to provide a production method of a Group III nitride semiconductor element having an excellent electrostatic discharge property and enhanced reliability.

In the inventive production method, the Group III nitride semiconductor element has an n-type layer, an active layer and a p-type layer, which comprise a Group III nitride semiconductor, on a substrate in this order, wherein, during or/and after growth of the n-type layer and before growth of the active layer, the growth rate of the semiconductor is reduced.

The invention discloses a method for growing a bismuth selenide high-index surface single crystal thin film on a silicon (211) substrate. The method comprises the following steps: 1), performing flashing silicon treatment or chemical etching treatment on a Si substrate having a crystal plane orientation of (211); 2), raising the temperature of a Bi beam source, depositing and growing a Bi buffer layer on the Si (211) substrate prepared in the step 1); 3), after the Bi buffer layer is grown in the step 2), adjusting the temperature of the Bi beam source, raising the temperature of a Se crackingbeam source, and starting to grow a Bi2Se3 nucleation layer; 4): after the growth of the Bi2Se3 nucleation layer is completed in the step 3, continuing to grow a Bi2Se3 high-index surface single crystal epitaxial thin film to obtain the bismuth selenide high-index surface single crystal thin film. According to the method, the Bi ultra-thin single crystal layer is adopted as a buffer layer, the low-temperature Bi2Se3 nucleation layer with a thickness of 3-5 nm is grown on the surface of the Bi buffer layer, then the growth temperature is appropriately increased to grow the Bi2Se3 high-index surface single crystal thin film epitaxial layer, and the Bi2Se3 high-index surface single crystal thin film having a relatively good crystallinity can be obtained.

The invention belongs to the technical field of novel material and relates to a preparation method of small-tube-diameter carbon nanotubes. The method includes generating an iron-containing metal-organic framework compound from iron ions and an organic ligand through a solvothermal process; after separation, washing and drying, soaking the compound in a solution containing rare earth ions and thenperforming carbonization in an inert gas to obtain a porous carbon material loaded with iron; and ejecting the porous carbon material, as a solid carbon source and a catalyst, from a plasma torch byadopting a high-temperature plasma process to gasify the carbon source and catalyst through high temperature so that carbon nanotubes grow during following downstream cooling. The porous carbon material derived from the metal-organic framework compound can enable ultrafine particle uniform distribution of original iron element and the porous carbon facilitates high-temperature gasification, thus providing an ultrafine nanometer catalyst and highly active carbon source for growth of ultrafine carbon nanotubes, and greatly increasing the growth efficiency of the small-tube-diameter carbon nanotubes. The method is an effective means for preparing the small-tube-diameter carbon nanotubes and single-walled carbon nanotubes, and has important practical application value.

The invention discloses (In, Mn) As nano-wires and a preparation method thereof. According to the present invention, the nano-wires are aligned along the crystal orientation, the epitaxy of the nano-wires grows on the substrate of the GaAs (001) single crystal, and the nano-wires transversely lie on the surface of the GaAs (001) single crystal; In(1-x)MnxAs (0.3<=x<=0.5) is the nano-wires, the sphalerite structure of the GaAs (001) single crystal is maintained, and the In(1-x)MnxAs is spontaneously aligned along the crystal orientation, such that the In(1-x)MnxAs has the magnetic anisotropy along the orientation, wherein the epitaxy of the In(1-x)MnxAs grows, and the In(1-x)MnxAs transversely lies on the surface of the GaAs (001) single crystal; according to the preparation method for the (In, Mn) As nano-wires, a molecular beam epitaxy technology and equipment are adopted, the GaAs (001) single crystal is adopted as the substrate, the Mn content in the elements of In and Mn is increased to 30-50%, and an intermittent growth way is adopted, such that the (In, Mn) As nano-wires are obtained, wherein the epitaxy of the In(1-x)MnxAs grows, and the nano-wires transversely lie on the surface of the GaAs (001) single crystal, and have the uniaxial anisotropy.

The invention provides an engineering bacterium of Geobacillusthermoglucosidasius and a construction method and application of the engineering bacterium. The construction method includes: through genetic engineering of Geobacillusthermoglucosidasius, introducing ribC (G199D) point mutation, sequentially knocking out purR, purA, ccpN and ldh genes, and then introducing an expression vector carryinga riboflavin synthesis gene cluster into the transformed engineering bacteria to obtain a series of high-temperature riboflavin-producing geobacillus engineering bacteria. The results show that yieldof riboflavin after fermentation of geobacillus after genetic engineering for 24 h is 520 mg/L; and through mixed fermentation with glucose and xylose for the strain, the yield can reach more than 1g/L. The engineering bacterium has advantages of high growth temperature and short generation time, can utilize an inexpensive carbon source, and can be used for large-scale production of riboflavin at low cost.

The invention discloses a preparation method of a long-wavelength LED epitaxial wafer. The preparation step comprises a step of placing an epitaxial substrate into an epitaxial growth reaction chamber, and a step of growing a CaN epitaxial layer on the epitaxial substrate, growing a GaN buffer layer on the surface of the epitaxial substrate, growing an n-type Can on the GaN buffer layer, growing aquantum well on the n-type CaN, and growing a p-type CaN on the quantum well, wherein the thickness of the CaN epitaxial barrier is h, the thickness is controlled to be larger than or equal to 0.35 micrometers and smaller than or equal to 6 micrometer. The electrical performance of an LED prepared by a gallium-nitride-based long-wavelength LED epitaxial wafer prepared by the invention is consistent with the electrical performance of a blue-green CaN-based LED.

The invention discloses a method for preparing a gallium-nitride-based photoelectric detector based on a graphene insertion layer. The method is mainly used for solving the problems that in the priorart, a nitride material epitaxially grown on a copper substrate is poor in quality and is not provided with a transition layer. The method comprises the preparation steps that a magnetron sputtering aluminum nitride thin film is arranged on an alpha-surface sapphire substrate; graphene is transferred to the magnetron sputtering aluminum nitride thin film, and a sapphire substrate covered with thegraphene is obtained and heated; a pulsed aluminum nitride transition layer is grown on the heated sapphire substrate; a low-temperature gallium nitride layer is grown on the transition layer to obtain a gallium nitride substrate; and a window graph is photoetched on the gallium nitride substrate, and an electrode is manufactured. Magnetron sputtering aluminum nitride and the pulsed aluminum nitride transition layer are adopted, the graphene serves as the insertion layer, thus gallium nitride can grow on the substrate with the large lattice mismatch constant, the quality of the gallium-nitride-based photoelectric detector is improved, and the method can be used for manufacturing gallium-nitride-based photoelectric devices.