77results about How to "Good repeat stability" patented technology

The invention discloses a method for preparing a polycarboxylic acid grafted copolymer superplasticizer. In the method, the preparation is implemented at the low temperature of 5-30 DEG C; a used initiating system is a complex initiating system which adopts the combination of one initiator I and various reducers R, or one reducer R and various initiators I or various initiators I and various reducers R, wherein the initiator (s) I is (are) selected from hydrogen peroxide, persulfate salt LS2O8 and a water-soluble azo initiator W, and the reducer (s) R is (are) selected from ascorbic acid and certain kinds of inorganic salt. The preparation method is simple, excellent in repetition stability and low in cost, does not require heating, and avoids toxicity and pollution; the prepared superplasticizer is high in water-reducing rate, and excellent in adaptability and slump-retaining capability, thereby being suitable for popularization and application.

The invention discloses a polymer matrix composite material with high PTC strength and stability and a preparation method thereof, and the composite material comprises UHMWPE and PVDF, CB and MWNT conductive filling materials which are treated by surface treatment by a titanate coupling agent, and an antioxidant 1010; the preparation method comprises the following steps: performing surface treatment of the CB and MWNT conductive filling materials by the titanate coupling agent, performing vacuum drying of PVDF and UHMWPE with a volume ratio of 1:1, adding PVDF into a torque rheometer, heating and melting for 2 min, adding another matrix of UHMWPE and the antioxidant 1010, wherein the amount of the antioxidant 1010 is 1% of the total mass of the matrix; mixing the mixture of the two matrixes for 10 min, adding the filling materials, mixing at 250 DEG C for 15 min; after melt blending, performing hot pressing with a constant temperature of 250 DEG C and a constant pressure of 18 MPa for 10 min to obtain the sample. The composite material of the invention has good conductivity and low room-temperature conductivity, and has a conductivity of up to 10-1 near a percolation threshold; the conductivity of the composite material can be changed by adjusting the contents of the filling materials in the composite material; the composite material has high PTC strength, good repetition stability, and reduced NTC effect.

The invention discloses a synthetic method and application of a urea monomer modified hydroxyl acrylic emulsion. The urea monomer modified hydroxyl acrylic emulsion is synthesized by a pre-emulsification semi-continuous seed emulsion polymerization method and applied to double-component aqueous plastic paint. According to performance test, functional groups of urea monomer interact with surface of polar plastic to enhance dry and wet adhesive force; meanwhile, hydroxy reacts with isocyanate to form a stereoscopic net structure to increase compactness of a film, water resistance and ethanol wiping resistance performances. The urea monomer modified hydroxyl acrylic emulsion prepared by the invention can carry out solidification reaction with aqueous isocyanate to gain good adhesive force and ethanol wiping resistance, so as to satisfy application requirements of low temperature solidified polar plastic paint.

The invention discloses a gypsum particle dispersing agent and a preparation method thereof. The dispersing agent is obtained by copolymerizing unsaturated polyoxyalkylene ether monomer, unsaturated carboxylic acids and derivative monomers thereof and other monomers which can be copolymerized with the monomers under a radical polymerization system. The gypsum particle dispersing agent has the advantages of high water-reducing rate, stable structure, delayed coagulation and the like; and the preparation method thereof has low energy consumption, high efficiency and good repeat stability.

A method for fixing pullulanase with chitosan magnetic nanoparticles comprises the steps as follows: (1) the chitosan magnetic nanoparticles are prepared; (2) amination treatment is performed on surfaces of the chitosan magnetic nanoparticles; (3) the chitosan magnetic nanoparticles after amination treatment and the pullulanase form covalent bonds in the presence of a cross-linking agent to fix the pullulanase. Compared with a traditional pullulanase fixing method, the method has the advantages that a carrier prepared with a chitosan hydrogel induction method is firstly used for fixing the pullulanase, and the method is simple in step, mild in condition and environment-friendly.

The invention relates to a process for preparing glyphosate by using glycine, which comprises the following steps: (1) putting paraformaldehyde, methanol and triethylamine in a reaction vessel, maintaining the reaction temperature to be 30-50 DEG C and stirring until the mixture is transparent; (2) adding the glycine to the reaction solution, and reacting to obtain condensation solution; (3) adding diisopropyl phosphate to the condensation solution, and reacting to obtain esterification solution; (4) adding hydrochloric acid to the esterification solution for acidification treatment to obtain hydrolysis solution; and (5) under the condition of normal pressure, controlling the temperature to be 80-130 DEG C for desolvation and deacidification, then under vacuum pressure, controlling the temperature to be 80-130 DEG C for deacidification by adding water two times, and finally adding deionized water and stirring for crystallization and leaching to obtain solid glyphosate. Compared with the prior art, the process has higher yield and convenient operation, saves the cost, and is suitable for industrial production due to production repeatability.

The invention discloses a K sub-group ALV (avian leukosis virus) fluorescent quantitation RT-PCR (reverse transcription-polymerase chain reaction) detection primer group and kit. The used primer pair and a probe are designed according to the gp85 segment of the K sub-group ALV sequence; the ALV-K can be specifically amplified; the intraspecific and interspecific specificity is very good; the 8.4*10 copies/muL viruses can be detected to the lowest degree; the sensitivity is 100 times of that of the ordinary PCR; the intra-assay variation coefficient and the inter-assay variation coefficient are lower than 5 percent. The result proves that the specificity is high; the sensitivity is high; the repeated stability is high; the amplification efficiency is high; the kit can be used for clinic ALV-K detection.

The invention discloses a polylactic acid/ MWCNT (multi-walled carbon nanotube) sensitive material with low percolation threshold and low limit of detection and an application of the polylactic acid/ MWCNT sensitive material. The sensitive material is a homogenously dispersed body prepared from high-molecular-weight polylactic acid as a matrix and MWCNTs as a conductive current carrier through stirring and compounding at 40-50 DEG C with a simple and low-cost solution mixing technology, wherein polylactic acid accounts for 95.0wt%-97.5wt%, and the MWCNTs account for 2.5wt%-5.0wt%. Due to the strong steric hindrance action of high-molecular-weight polylactic acid and the good self-organization action of the high-molecular-weight polylactic acid on the surfaces of the CNTs, the sensitive material has good dispersibility, and the percolation threshold is as low as 2.9wt%; a composite film sensing element with smooth surface can be assembled conveniently from the sensitive material and is applied to chloroform vapor detection, the sensitive material has higher response intensity, rapid response and recovery performance and good repeatability and stability, and the limit of detection of chloroform vapor is as low as 10 ppm. The sensitive material can be taken as a novel gas sensor for rapid detection of indoor and outdoor environmental gas.

Disclosed is a liquid chip detection method for four types of pathogens of porcine virus diarrhea. The method includes firstly, designing and synthesizing corresponding upstream primers, downstream primers and probes to gene N<pro> of virus BVDV, gene N of virus TGEV, gene M of virus PEDV and gene VP6 of virus PRoV respectively, subjecting 5'-ends of all the downstream primers to biotin labeling, and modifying 5'-ends of all the probes with amino group (NH2(CH2)12); choosing microspheres with different color coding and coupling the same with the probes of BVDV, TGEV, PEDV and PRoV respectively, mixing the four types of probes which are coupled with the microspheres to obtain a probe mixture; hybridizing amplified products obtained by biotinylation with the probe mixture coupled with the microspheres to obtain a hybridized product, subjecting the hybridized product to liquid chip detection, and determining detection results according to MFI values. The method can be applied to detection of four types of pathogens of porcine virus diarrhea simultaneously and has the advantages of good specificity, good repeatability and stability and high sensitivity.

An electrophotographic photoreceptor includes a photosensitive layer including a charge generating material, a charge transporting material and a binder resin in a single layer, formed on an electrically conductive substrate. The single photosensitive layer includes an upper photosensitive layer portion and a lower photosensitive layer portion. The upper photosensitive layer portion has a higher concentration of the electron transporting material than that of the lower photosensitive layer portion. A method of preparing the electrophotographic photoreceptor, and an electrophotographic imaging apparatus employing the electrophotographic photoreceptor are provided. The single-layered type electrophotographic photoreceptor according to the present invention shows high sensitivity and excellent repetition stability of electrical properties, while still having advantages of a conventional single-layered photoreceptor, thereby being able to have highly practical applications.

According to the composite gas-sensitive material and the preparation method thereof, and the ethanol gas sensor and the preparation method thereof disclosed by the invention, a trititanium carbide material and a cobaltosic oxide material derived from a metal organic framework are combined and applied to the gas sensor; the interdigital electrode is coated with a cobaltosic oxide-trititanium carbide composite material coating film derived from a metal organic framework, so that the gas-sensitive response of traditional cobaltosic oxide to ethanol is greatly enhanced, the selectivity to ethanol is improved, the sensitivity is high, and the highest sensitivity to 50 ppm ethanol can reach 185. Compared with a traditional cobalt oxide gas sensor, the sensitivity of the cobalt oxide gas sensor is improved by 15 times, even if the gas concentration is 1 ppm, detection can be conducted, the response speed is high, and good repeatability and stability are achieved.

The invention belongs to the field of olefin polymerization, and more specifically provides a catalyst component used for olefin polymerization, and a preparation method and applications thereof. The preparation method comprises following steps: a magnesium halide alcohol adduct carrier, a titanium compound, and an internal electron donor are subjected contact reaction, wherein the internal electron donor contains a carboxylic acid diol ester and a phosphate, and the magnesium halide alcohol adduct carrier is prepared via following steps: a magnesium halide alcohol adduct melt is delivered through a structure unit provided with holes for contact with a liquid cooling medium under increased pressure. The invention also provides a catalyst used for olefin polymerization, and applications thereof. Compared with conventional catalysts, the catalyst synthesized from the carrier via the preparation method disclosed in the invention possesses following advantages: the catalyst possesses excellent steric directional catalytic performance, and foundation is provided for development of polypropylene resin with high additional value.

The invention relates to the field of olefin polymerization, and specifically provides a catalyst component used for olefin polymerization and a preparation method and application thereof. The preparation method comprises a step of subjecting a magnesium halide adduct, a titanium compound and an aromatic carboxylate compound to a contact reaction. The magnesium halide adduct is prepared through the following steps: (1) mixing aquo MgX1Y, R1OH and an alkoxy benzoyl compound and heating the obtained mixture so as to obtain a liquid magnesium halide adduct, or mixing anhydrous MgX1Y, R1OH, the alkoxy benzoyl compound and water and heating the obtained mixture so as to obtain the liquid magnesium halide adduct; and (2) allowing the liquid magnesium halide adduct to penetrate through a structural unit with holes to a liquid cooling medium under the action of pressure in the presence of an inert liquid medium, and carrying out quenching formation and drying. The invention provides a catalyst system used for olefin polymerization and application thereof, and an olefin polymerization method. The catalyst component synthesized from an adduct carrier prepared by using the method has improved hydrogen sensitivity when used for olefin polymerization.