75results about How to "Reduce steric hindrance effect" patented technology

The invention discloses a halogen-free resin composition and a low-fluidity prepreg thereof. The halogen-free resin composition comprises, by weight, 20-80 parts of an epoxy resin composition, 10-50 parts of phenoxy resin, 10-50 parts of a flame retardant, 3-30 parts of a toughening agent, 10-80 parts of an inorganic filler, 1-10 parts of a curing agent, 0-5 parts of an accelerator and 0-80 partsof an additive. The halogen-free resin composition obtained by modifying common epoxy resin with bisphenol F phenoxy resin, liquid epoxy resin and long chain-containing aliphatic epoxy resin has low viscosity and good wettability, and the low-fluidity prepreg produced from the halogen-free resin composition has the advantages of high flexibility, high Tg and bonding strength, excellent heat resistance, greenness, environmental protection, no resin dust, and realization of long-term preservation.

The invention relates to an amphiphilic self-assembled nanomicelle based on nano Low-generation PAMAM (polyamidoamine) dendrimer and application thereof, particularly obtained conjugating low-generation PAMAM dendrimer and a hydrophobic agent and self-assembling in water via ultrasonic vibration. The nanomicelle has active molecules or a prodrug with drug loading capacity; the chemical conjugation of the hydrophobic agent and the low-generation PAMAM dendrimer helps improve the defects of poor solubility of the hydrophobic drug and low bioavailability, and a new idea is provided to solve the problem that traditional clinical chemotherapeutics are high in toxicity and low in safety coefficient; the nanomicelle can also function as a nanocarrier to carry other hydrophobic drugs, enabling joint use of drugs and enhancing therapeutic effect.

The invention relates to the field of medical devices, in particular to a preparation method of a surface-heparinized anticoagulation medical device based on ionic bond-covalent bond synergistic action. The method comprises the following steps: firstly, fixing heparin on the surface of a medical device by utilizing a hydrophilic polymer modified by low-molecular-weight hyperbranched polyethyleneimine as a side chain in an ionic bond combination manner; and furthermore, grafting a stable heparin coating through covalent bonds, so as to obtain the anticoagulant biomedical device with high anticoagulant activity and high anticoagulant stability. The device has a wide application value in the field of biomedical treatment. The method is simple in preparation process, high in controllability and low in material price, does not involve toxic reagents in the experiment process, has universality for various medical device structures, and is suitable for industrial production.

The invention discloses a deep desulfurization hydrotreatment method of diesel oil. The method comprises the following steps that a diesel oil raw material enters a hydrogenation reactor and contactsa hydrogenation catalyst bed layer to carry out a hydrogenation reaction, and the reaction product flows out of the reactor, wherein the hydrogenation catalyst bed layer is filled with at least two stages of vulcanization-state hydrogenation catalysts in a grading manner along the material flow direction, the metal active phase crystal lengths of each stage of the vulcanization-state hydrogenationcatalyst are increased stage by stage along the material flow direction, and the lamellar crystal layer number is reduced stage by stage. According to the catalyst grading method disclosed by the invention, the matching reaction of the molecular size and structure of the reactants in each section and an active phase structure can be fully realized so as to effectively utilize the active center ofthe catalyst, improve the coupling reaction performance of the active center structure and the molecular structure, substantially improve the desulfurization activity and the stability of the whole system on reactants, significantly improve the desulfurization depth of diesel oil and produce ultralow-sulfur diesel oil.

The invention relates to a method for preparing a grape skin tannin modified phenolic resin adhesive. The method comprises the following process steps: (1) preparation of a grape skin tannin extract:(2) biodegradation of the grape skin tannin extract: obtaining the grape skin tannin extract with a low molecular weight and low degree of polymerization by sulfite extraction and biodegradation; (3)preparation of tannin modified phenolic resin: using the grape skin tannin extract, phenol, formaldehyde, an alkali solution and water as raw materials, performing a secondary polycondensation reaction by a secondary charging method of the formaldehyde and the alkali solution to prepare the grape skin tannin modified phenolic resin adhesive; (4) preparation of a plywood. The method has the advantages that: (1) condensed tannins with low molecular weight and low degree of polymerization are prepared by a sulfite extraction and biodegradation combination method, so that the space steric effect in the polycondensation reaction is reduced and the adhesive forming properties of phenolic resin are improved; (2) the preparation process is simple, the operation is easy, and the prepared phenolic resin has good properties.

The invention relates to a double-cross-linking chemical synthesis method of a citrinin-protein-coupled antigen and a preparation method of an anti-citrinin monoclonal antibody, belongs to the field of biotechnology. The synthesis method of the citrinin-protein-coupled antigen comprises the following steps that: the citrinin and a double-cross-linking agent (C2H3O)-(CH2)n-(C2H3O) react at first and is then coupled with a carrier, glycine is used for occlusion after reaction, and separation and purification are carried out finally, thereby obtaining the citrinin-carrier-coupled antigen. The preparation method of the anti-citrinin monoclonal antibody comprises the following steps: carrying out cell fusion and screening with the hybridoma technique to obtain a hybridoma cell line of the anti-citrinin monoclonal antibody with stable secretion, preparing ascitic fluid, and purifying, thereby obtaining the anti-citrinin monoclonal antibody. The invention has the advantages of mild preparation conditions, simple operation and controllable process. The obtained anti-citrinin monoclonal antibody has high specificity and high affinity, and can be further used for preparation of the enzyme linked immunosorbent assay kit or test paper card for citrinin detection.

The invention belongs to the field of clinical medical diagnosis and especially relates to a microballoon-based cup-type time resolution fluorescent procalcitonin analysis kit, a preparation method and an application thereof. The kit comprises a detection reaction cup, a fluorescence labeling antibody and a cleaning fluid. The method comprises the following steps of: in specific detection process, firstly drawing a standard curve; adding a to-be-detected sample into the detection reaction cup; adding the fluorescence labeling antibody; incubating at 30-40 DEG C; washing with the cleaning fluid and removing the uncombined antibody and fluorescence labeling antibody; and comparing a fluorescence signal with the standard curve, thereby acquiring the concentration of procalcitonin of the to-be-detected sample. The detection method for the procalcitonin is ultrahigh in sensitivity, so that the automatic operation can be easily realized; the reaction temperature is uniform; the method is not influenced by the environmental factor; the accuracy is better; the precision is excellent.

The invention relates to a nylon material of a pin-type composite insulator cap-shaped connector for a power grid power transmission and distribution line and a forming method. The nylon material comprises the following components in percentage by mass: 62%-66% of nylon resin, 28%-33% of glass fiber, 3%-6% of a toughening agent, 0.2%-0.5% of a main antioxidant, 0.2%-0.5% of an auxiliary antioxidant, 0.2%-0.5% of an ultraviolet absorbent, 0.2%-0.5% of a light stabilizer and 1%-3% of a wear-resistant additive, the viscosity of the nylon resin is 3.2 +/-0.01; the grafting rate of the toughening agent is 0.8 to 1.2%; the nylon resin is PA66 polyhexamethylene adipamide, PA6 polyamide 6 or a mixture of the PA66 polyhexamethylene adipamide and the PA6 polyamide 6. After polymerization processing,the material performance is excellent, the mechanical performance, the electrical performance, the environmental aging resistance, the high and low environmental temperature resistance and the material wear resistance of the composite product are excellent, and the safe use condition of the product is met.

The invention discloses a fluidized bed catalyst grading method which comprises the following steps: heavy oil raw materials and hydrogen enter from the bottom of a reactor and are in contact with a hydrogenation catalyst bed layer for hydrogenation reaction, and a reaction product flows out from the top of the reactor; wherein the grading is filled with at least two stages of sulfurized hydrogenation catalysts; wherein from bottom to top in the material flow direction of the sulfurized hydrogenation catalysts at each stage, the average length of metal active phase crystals is gradually increased, the average number of lamellar crystal layers is gradually reduced, the content of active components is gradually reduced, the probable pore diameter is gradually reduced, the stacking density isgradually reduced, and the particle diameter is gradually reduced. The metal active phase is active metal sulfide. According to the method, the specific catalyst gradation is adopted, so that the active center of the catalyst can be effectively utilized, the coupling reaction performance of an active center structure and a reactant molecular structure is improved, the stability of hydrogenation reaction, such as demetalization, desulfurization and denitrification, of the whole system is greatly improved, and deep hydrogenation of heavy oil is facilitated.

The invention discloses a synthesis method of tert-butyl acetoacetate. The method comprises the following steps that tertiary butanol and catalysts are added into a reaction container; the catalysts are selected from aliphatic amine catalysts or tertiary amine catalysts; or the catalysts are fatty amine catalysts and tertiary amine catalysts; the catalysts are one kind of catalysts or several kinds of catalysts proportioned at any proportion; the temperature is raised to 20 to 120 DEG C; diketene is dropwise added; in the reaction process, the reaction temperature is controlled to be 20 to 150DEG C; after the dripping is completed, the temperature is controlled at 20 to 150 DEG C; heat insulation is performed for 0.5 to 8 hours to obtain tert-butyl acetoacetate raw ester; the mole ratio of the tertiary butanol to the diketene is (1 to 2) to1; the addition of the catalyst is 0.1 weight percent to 2 weight percent of the total amount. The process is used for synthesizing the tert-butylacetoacetate; the conversion rate of the diketene reaches 100 percent; the finished product yield reaches 94 percent or higher; the product content reaches 99 percent or higher. By using the process,the synthesis yield is greatly improved; the preparation cost is reduced; meanwhile, the three-waste quantity is reduced; no corrosion is caused on the equipment; better economic and environment-friendly effects can be achieved.

The invention belongs to the field of clinical medical diagnosis and especially relates to a microballoon-based cup-type time resolution fluorescent troponin I analysis kit as well as a preparation method and application thereof. The kit comprises a detection reaction cup, a fluorescence labeling antibody and a cleaning fluid. The method comprises the following steps of: in a specific detection process, firstly drawing a standard curve; adding a to-be-detected sample into the detection reaction cup; adding the fluorescence labeling antibody; incubating at 30-40 DEG C; washing with the cleaning fluid and removing the uncombined antibody and fluorescence labeling antibody; comparing a fluorescence signal with the standard curve, thereby acquiring the concentration of troponin I of the to-be-detected sample. The detection method for the troponin I is ultrahigh in sensitivity, so that the automatic operation can be easily realized; the reaction temperature is uniform; the method is not influenced by the environmental factor; the accuracy is better; the precision is excellent.

The invention discloses a cup-type time-resolved fluorescent analysis method and kit for NT-proBNP based on microspheres. The method comprises the following steps: coating the interior surface of a detection reaction cup with a NT-proBNP monoclonal or polyclonal antibody; subjecting time-resolved fluorescent microspheres and the NT-proBNP monoclonal or polyclonal antibody to crosslinking via a covalent bond so as to prepare a fluorescence-labeled antibody; adding a to-be-detected NT-proBNP sample into the coated detection reaction cup, then adding the fluorescence-labeled antibody and carrying out incubation at 25 to 40 DEG C; carrying out cleaning to remove unbounded antigen and fluorescence-labeled antibody and testing a fluorescence signal in the detection reaction cup under the condition of excitation by exciting light with a wavelength of 340 to 380 nm; and comparing the fluorescence signal with a standard curve so as to obtain the concentration of NT-proBNP in the to-be-detected NT-proBNP sample. The method and kit provided by the invention can complete detection in short detection time, shortens detection time and improves detection sensitivity.

The invention relates to a formula and application of a xylene solvent for improving solid phase synthesis efficiency of polypeptide, which is characterized in that the formula of the xylene solvent comprises dimethylformamide DMF, dichloromethane DCM and xylene DMB at a volum ratio of 1:1.5-2.5:0.15-1.0. The invention effectively reduces the cost for synthesizing the polypeptide, reduces the steric hindrance effect of hydrophobic lateral chains and blocking groups of amino acid, shortens the reaction time and accelerates the polypeptide synthesizing speed, and the polypeptide has high yield and few impurities.

The invention relates to a microarray chip capable of detecting genomic DNA of various fungi and a preparation method of the microarray chip. The microarray chip comprises a modified chip solid-phasecarrier, and a modified gene chip probe, wherein the modified gene chip probe comprises the following structures according to the direction of 5'-3': a 5' modified group-Cn-(dT) m-oligonucleotide chain 3', oligodeoxynucleotide is selected from nucleotide sequences of genomic DNA specific regions of two or more fungi of Candida albicans, Candida glabrata, Candida parapsilosis, Aspergillus, Candidatropicalis and Cryptococcus, or complementary sequences thereof. According to the embodiment of the invention, the modified gene chip probe in the microarray chip effectively reduces the steric hindrance effect of the probe and a PCR product during specific binding, the combination of the two modification modes plays a synergistic role, and the genomic DNA of various fungi can be well detected.

The invention relates to an epoxy amino chromatography medium and a preparation method thereof. The epoxy amino chromatography medium is formed by ring-opening reaction of a polysaccharide microsphereand an amino epoxy compound. The preparation method comprises reaction of the polysaccharide microsphere and the amino epoxy compound. The epoxy amino chromatography medium has a long intermediate arm, high protein binding capacity, and simple preparation method.

The invention discloses an immunofluorescence chromatography detection card and method for synchronously detecting the contents of florfenicol and trimethoprim in poultry eggs, and aims to provide an immunofluorescence chromatography detection card and method which are simple and time-saving in sample pretreatment operation, free of blow-drying, high in detection method sensitivity, suitable for on-site instant detection and capable of synchronously detecting florfenicol and trimethoprim in poultry eggs. The card is characterized by comprising a bottom plate, an absorbent paper pad, a reaction film, a combination pad and a sample pad are sequentially connected to the bottom plate from left to right, a florfenicol detection line T1, a trimethoprim detection line T2 and a quality control line C are marked on the reaction film, and florfenicol detection microspheres, trimethoprim detection microspheres and goat anti-chicken IgY polyclonal antibody labeled microspheres are coated on the combination pad; the invention belongs to the technical field of biological detection.

The invention provides a method for detecting a protein complex in a biological sample. The method comprises the steps of: covalent crosslinking, denaturation treatment, solution replacement, co-immunoprecipitation and mass spectrometry. According to the method, a three-dimensional structure of protein is destroyed through the denaturation treatment step to disperse a peptide chain, so that the steric hindrance effect of the peptide chain is reduced, and the protein complex can be better recognized by a specific antibody. Moreover, due to denaturation treatment, an antigenic determinant buriedin a hydrophobic center of the peptide chain is exposed to serve as a linear epitope, an antibody directed at the linear epitope can be adopted for co-immunoprecipitation, and a novel thought is provided for co-immunoprecipitation. The detection method disclosed by the invention is beneficial to research on the interaction of the protein complex and the protein.