14results about How to "Increase cell density" patented technology

The invention relates to construction of a Ralstonia strain capable of producing isobutanol by utilizing fructose and carbon dioxide and application of the Ralstonia strain. The construction method comprises the following steps: firstly, knocking out bkdA and bkdB genes in tricarboxylic acid cycle of the Ralstonia H16 to obtain a recombinant strain H1601; then, a PHB operator phaCAB in the H1601 is knocked out, and an alsS gene of bacillus subtilis and ilvC and ilvD genes of Ralstonia are introduced into the site, so that a recombinant strain H1602 is obtained. And finally, introducing yqhD and kivD gene expression cassettes of escherichia coli into the H1602, and constructing a recombinant strain H1603 capable of synthesizing isobutanol by using fructose and carbon dioxide. The strain can be used for synthesizing isobutanol through heterotrophic or autotrophic fermentation by taking carbon dioxide and fructose as carbon sources, the operation is simple and convenient, and higher yield can be obtained.

The invention relates to the field of novel polymer materials, and particularly discloses a degradable expandable polylactic acid polymer foam material and a preparation method thereof, the degradable expandable polylactic acid polymer foam material comprises the following raw materials: a polylactic acid-starch-polyamide blending modified mixture, polylactic acid foam material waste leftover materials, a foaming agent, a nucleating agent and an activating agent; the preparation method comprises the following steps: melting and mixing polylactic acid, acylated starch and polyamide in proportion to prepare a polylactic acid-starch-polyamide blending modified mixture, weighing the polylactic acid-starch-polyamide blending modified mixture, mixing the polylactic acid-starch-polyamide blending modified mixture with the polylactic acid foaming material waste leftover materials, the foaming agent, the nucleating agent and the activating agent, and performing extrusion molding to obtain the polylactic acid foaming material. Extruding and pelletizing to obtain foaming master batch, and foaming and forming; the preparation method has the characteristics that the expandable performance of the polylactic acid material is improved, and the prepared polylactic acid foam material is more uniform in cell size distribution, small in cell size and excellent in mechanical property.

The invention provides a wide bandgap semiconductor trench gate MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) structure and a manufacturing method thereof. In the structure, an N + current expansion layer is positioned in an upper region of an N-epitaxial layer; the P-well region is located on the N + current expansion layer, and the source N + region is located on the P-well region; the plurality of trench gate electrodes are arranged at intervals along the horizontal direction, and a first source P + region is arranged between every two adjacent trench gate electrodes in the middle region; the trench gate electrode penetrates through the source N + region, the P-well region and the N + current expansion layer in the longitudinal direction and extends into the N-epitaxial layer; a second source P + region is arranged at the bottom of the trench gate electrode; the P-type connection region is connected with the plurality of second source P + regions in the second direction; an interlayer dielectric layer is arranged above the trench gate electrode; the N + contact region is arranged at the first source P + region in an extending mode in the first direction, and the Schottky contact region is located above the N + contact region. The structure can improve the current density of the device, improves the conduction characteristic of the device, can also form a net-shaped P-type region protection gate electrode, and improves the dynamic reliability of the gate electrode of the device.

The invention relates to the technical field of rubber foaming materials, and discloses a preparation method and application of a microporous EPDM rubber foaming material. The anti-aging co-crosslinking agent structure contains a multi-maleimide group, which can generate chemical crosslinking with the EPDM rubber, and the crosslinking activity of the molecular chain is enhanced, so that the carbon dioxide dissolved in the matrix is ​​not easy to diffuse out of the matrix, and the nucleation sites are gradually increased, which can support the formation of the pore structure and maintain the integrity of the pore structure, so as to form a dense microporous structure; the imide heterocycle, triazine ring and benzene ring in the anti-aging co-crosslinking agent have strong high temperature resistance. In the rubber vulcanization process, the double bonds are opened to participate in the crosslinking reaction, and free radical active species are formed, which undergo a co-crosslinking reaction with the EPDM rubber, improve the crosslinking network structure, improve the heat air aging resistance and salt spray aging resistance of the EPDM rubber, and enhance the elastic recovery ability of the rubber.

The invention provides a method for culturing beneficial algae by resource utilization of cyanobacterial blooms, which comprises the following steps: 1, obtaining cyanobacterial (microcystis) blooms, and concentrating the cyanobacterial (microcystis) blooms until the concentration of chlorophyll a is 80-150mg / L; 2, carrying out continuous hydrodynamic disturbance on the high-concentration cyanobacterial bloom, wherein the disturbance intensity is suitable for preventing the cyanobacterial bloom from blackening and stinking; 3, continuously disturbing for 20-60 days to obtain cyanobacterial bloom which turns light yellow green or white; 4, tap water is used for diluting cyanobacterial blooms with changing colors, the concentration during dilution is 0.5-2.3 mL / cm < 2 >, and beneficial algae such as diatom and green algae are inoculated for culture under the conditions of normal temperature and weak light; and 5, when the culture is performed for 12-30 days, the growth density of the beneficial algae reaches the highest peak, and the cell density of the beneficial algae can reach up to 2.5 * 10 < 6 >-5.6 * 10 < 7 > cells / cm < 2 >. According to the method, algal toxin can be removed, beneficial algae such as diatom and green algae can be cultured through resource utilization of the cyanobacterial bloom, and a new way is provided for control and resource utilization of the cyanobacterial bloom.

The invention relates to the technical field of foaming polyurethane, and discloses a foamable polyurethane composition, a modified polyurethane and a preparation method thereof, a polyurethane foam material and a preparation method thereof, wherein the composition comprises polyurethane, polar monomer grafted polypropylene and an amino compound, and based on the total weight of the composition, the content of the polyurethane is 70-95wt%, the content of the polar monomer grafted polypropylene is 3-29.9wt%, and the content of the amino compound is 0.1-3wt%. The invention modifies the polyurethane by adopting the polar monomer grafted polypropylene and the amino compound, and the polyurethane cooperates with the polar monomer grafted polypropylene and the amino compound, so that the prepared modified polypropylene has better viscoelastic properties, thereby making the prepared polyurethane foam material have better foaming effect.

This invention relates to the field of wastewater treatment technology, specifically to a microbial preparation, its preparation method, and its application, comprising: a composite microbial agent; and a calcium alginate / polyvinyl alcohol interpenetrating network aerogel carrier loaded with the composite microbial agent; the aerogel carrier contains uniformly dispersed modified nano-attapulgite clay. The microbial preparation of this invention exhibits good wastewater treatment performance and long-lasting effect.

The invention discloses a nutrient highly-concentrated culture medium and a method for promoting high-density growth and high expression of CHO cells, and belongs to the technical field of cell culture. The invention provides a serum-free animal-source-free highly-concentrated mammalian cell culture medium formula with definite chemical components, wide nucleic acid components are added to promote cell growth and metabolism, the inhibition effect of other high-concentration components is relieved, the cell density and motility rate are remarkably improved, and the cell culture medium is suitable for large-scale production. Meanwhile, the high-concentration taurine is added for synergistically improving the cell density and promoting the expression of the target protein, so that the method is suitable for large-scale culture of various CHO cells, and the large-scale production cost of the target protein is reduced.

The invention relates to the technical field of MOS (Metal Oxide Semiconductor) semiconductors, and discloses a process for improving the cellular density of a double-groove MOSFET (Metal Oxide Semiconductor Field Effect Transistor), which comprises the following steps of: injecting phosphorus elements with different concentrations into a semiconductor epitaxial layer to form an N substrate layer and a drift layer; continuing ion implantation of boron elements on the upper layer of the drift layer to form a P body region; performing ion implantation at the center of the P body region to form an N well layer, and performing ion implantation at the upper layer P body region to form a P well layer and a P-well layer; etching the surface of the semiconductor epitaxial layer by an etching process to form a rectangular groove; and depositing metal aluminum to two sides of the rectangular groove so as to form the L-shaped source electrode. In the preparation process, the L-shaped source electrode is in contact with the N well layer by adopting an inward sunken design, the power consumption of the MOSFET device is not easily reduced due to heat accumulation even if the prepared MOSFET device adopts a smaller size, and the cellular density of the MOSFET device can be greatly improved by adopting the source electrode inward sunken process design.

The present invention relates to the technical field of polymer foaming materials, and provides a polyamide elastomer foam material with a bimodal pore structure and a preparation method thereof. The present invention utilizes foaming gas CO2 to perform saturation treatment on a polyamide elastomer sheet solid sample, wherein the first saturation treatment is to perform a melting treatment on the polyamide elastomer to eliminate crystals; by regulating the temperature and time of the second saturation treatment, the weight crystallization degree of the polyamide elastomer is regulated to be 1.1-10%, thereby preparing a polyamide elastomer foam material with a bimodal structure having controllable pore size; since the temperature and pressure of the second saturation treatment are under the supercritical condition of CO2, the foaming temperature range is widened, and not only the polyamide elastomer foam material with a bimodal pore structure is obtained, but also the foaming ratio of the polyamide elastomer foam material is improved.

The invention relates to the technical field of polymer composite material processing, and discloses a blending extrusion preparation method of a plant fiber reinforced biodegradable foaming material, which comprises the following steps: firstly, preparing polycaprolactone glycol, zinc isoocatanoate and absolute ethyl alcohol into a polar cosolvent system; the plant fibers are deagglomerated by utilizing the permeation effect of the solvent and a hydrogen bond damage mechanism; then, in a first extruder, a melt sealing material is formed through base resin in a specific proportion to maintain the vacuum degree of a middle-section devolatilization area, and it is ensured that absolute ethyl alcohol is completely removed; in the rear section of the extruder, zinc isoocatanoate immobilized on the surface of the fiber is utilized to catalyze the polyfunctional group epoxy chain extender to generate in-situ ring opening grafting, and a flexible transition layer is constructed on the interface of the fiber and the resin. The problems that plant fibers are prone to agglomeration and poor in resin interface bonding force are solved, the melt strength of a composite system is improved, and the prepared foaming material is uniform in foam hole and stable in performance and has good industrial application prospects.

The invention relates to a high-foaming-rate and high-stability fully-degradable biomass-based foaming material which is prepared by taking PLLA, PDLA, biopolyester, microcrystalline cellulose and surface epoxy grafted carbon nanotubes as main raw materials, and promoting comprehensive regulation and control of melt characteristics and crystallization characteristics through free radical reaction crosslinking and chain extension between matrixes and a stereocomplex. A two-stage melt conveying and extrusion continuous supercritical foaming process is adopted to realize a high-density closed-cell foam structure with high foaming ratio and bimodal pore size distribution of the foam, and the foam has high foaming ratio, high strength and toughness, excellent form stability and low thermal conductivity, can be fully degraded, and can be applied to the light-weight buffer fields of packaging, industry, building and the like.

The invention discloses a production method of BVDV and IBRV genetic engineering subunit fusion protein, which comprises the following steps: inoculating CHO seed cells of fusion expression BVDV-IBRV protein to a basic culture medium, carrying out feed supplement culture, inoculating on the 0th day, supplementing 3% of feed every day from the 1st day to the 6th day, then supplementing 3% of feed every other day, and finishing the feed supplement on the 12th day. Due to the fact that CHO cell genes are prone to denaturation, in order to express different foreign proteins, different culture conditions, different culture media, different material supplementing modes and the like can influence the density, activity and metabolism of CHO cells, the final target yield and the like.

This invention discloses a method for preparing silicon-carbon composite anode materials using porous graphite. First, a porous carbon material with a large number of uniformly distributed nano- to micron-sized pores is prepared using a physical foaming method, and then graphitized at high temperature to obtain porous graphite. Next, the porous graphite is pulverized to obtain graphite powder with a cratered surface structure, and then mixed with a certain proportion of nano-silicon and ball-milled to embed the nano-silicon into the cratered structure on the graphite powder surface. Finally, the mixed material is carbon-coated to obtain a silicon-carbon composite anode material for lithium-ion batteries. Applications of this composite material are also provided. In this invention, nano-silicon and graphite have good electrical contact, greatly improving the electrochemical performance of the silicon-carbon composite anode material. Simultaneously, graphite can buffer the volume expansion of the silicon material. The cratered structure on the graphite surface improves the lithium intercalation reaction of the silicon-carbon composite anode material, improving the rate capability and low-temperature performance of lithium-ion batteries.