磁芯（PQ65）

COMPOSITE SWEETENING AGENT AND PRODUCTION METHOD THEREFOR

A sweetening agent composite which tastes good, consisting of rebaudioside D and rebaudioside M, which are in a weight ratio of rebaudioside D: rebaudioside M = 1.5-9: 1. The present sweetening agent is synthesized by means of whole-cell catalysis and is obtained by catalyzing a substrate for reaction in the presence of sucrose, zinc chloride and trisodium citrate with rebaudioside A being used as the substrate and a recombinant microorganism which contains an EUGT11-encoding gene and a UGT76G1-encoding gene being used as the catalyst.

POWER SUPPLY SYSTEM AND METHOD

A power supply system and method. The power supply system comprises: a power grid input unit (101) and a diesel generator input unit (102), separately used for supplying an alternating current to a power supply unit (104); an automatic transfer switch unit (103), connected to the power grid input unit and the power supply unit or connected to the diesel generator input unit and the power supply unit; the power supply unit, used for converting the received alternating current into a direct current; and a control unit (105), used for monitoring a current load current and current diesel generator power, and determining to turn off a preset number of power supply loads according to a magnitude relationship between the current diesel generator power and the current load power and according to priority levels of current loads. By means of the power supply system and method, the power supply time is prolonged and the power supply reliability is improved.

METHOD EMPLOYING RECOMBINANT YEAST FOR CATALYTIC SYNTHESIS OF REBAUDIOSIDE M

Provided is a method employing recombinant yeast for catalytic synthesis of rebaudioside M. The method comprises using rebaudioside A as a substrate and a recombinant yeast as a catalyst; catalyzing the reaction of the substrate in the presence of sucrose, zinc chloride, and trisodium citrate; filtering; heating the filtrate to deactivate a recombinant microorganism so as to obtain a crude solution of rebaudioside M; followed by purifying and concentrating to obtain rebaudioside M. The recombinant yeast contains a EUGT11 encoding gene and a UGT76G1 encoding gene. The pgm gene, glgC gene and agp gene are knocked out of the recombinant yeast, and the transformation rate thereof is more than 90%.

Bonding agent for surface treatment of circuit board and preparation method of bonding agent

The invention discloses a bonding agent for surface treatment of a circuit board and a preparation method of the bonding agent. The bonding agent comprises the following components: 15-25 g/L of a mercapto molecule and nitrogen heterocyclic molecule composition, 15-30 g/L of a coupling agent, 3-6 g/L of a dispersing agent, 5-10 g/L of a penetrating agent, 2-5 g/L of an additive and the balance of deionized water. According to the bonding agent prepared by the invention, the added polyvinylpyrrolidone can be used as a dispersing agent on one hand, and belongs to a water-soluble amide high-molecular polymer on the other hand, and methylene of a pyrrolidone ring in a molecular chain of the polyvinylpyrrolidone is a non-polar group, so that the polyvinylpyrrolidone can be bonded with 3, 3 '-biphenyl through an N-H or O-H bond in a molecule in a water solution; according to the bonding agent, 1, 5-dimethyl-2-mercapto benzimidazole and 1, 3-di (1H-benzotriazolyl) propane interact with each other ...

Brown oxidation liquid for high-frequency high-speed circuit board and preparation method thereof

The invention discloses browning liquid for a high-frequency high-speed circuit board and a preparation method of the browning liquid. The browning liquid comprises the following components: 80-120 g/L of 98wt% concentrated sulfuric acid, 10-20 g/L of 30wt% hydrogen peroxide, 8-15 g/L of a compound corrosion inhibitor, 20-50 g/L of a silane coupling agent, 40-70 g/L of copper sulfate, 5-15 g/L of an impregnating compound, 5-8 g/L of a dispersing agent and the balance of deionized water. According to the browning liquid, under the combined action of the corrosion inhibitor and the impregnating compound, low roughness is formed on the copper surface, meanwhile, good binding force is formed between a corrosion inhibition film and the copper surface as well as between the corrosion inhibition film and resin, and the problem that the binding strength between copper and resin is reduced due to reduction of the copper surface roughness is solved; and the browned copper plate has a wide application ...