Abstract: The present invention relates to the field of noninvasive prenatal gene testing by high-through sequencing technologies. Particularly, the present application relates to a method for determining the content of cell-free fetal DNA in maternal peripheral blood.

Abstract: A catalytic cracking process includes a step of contacting a cracking feedstock with a catalytic cracking catalyst in the presence of a radical initiator for reaction under catalytic cracking conditions. The radical initiator contains a dendritic polymer and/or a hyperbranched polymer. The dendritic polymer and the hyperbranched polymer each independently has a degree of branching of about 0.3-1, and each independently has a weight average molecular weight of greater than about 1000. The catalytic cracking process is beneficial to enhancing and accelerating the free radical cracking of petroleum hydrocarbon and promoting the regulation of cracking activity and product distribution; by using the process disclosed herein, the conversion of catalytic cracking can be improved, the yields of ethylene and propylene can be increased, and the yield of coke can be reduced.

Abstract: A catalytic cracking process includes a step of contacting a cracking feedstock with a catalytic cracking catalyst in the presence of a radical initiator for reaction under catalytic cracking conditions. The radical initiator contains a dendritic polymer and/or a hyperbranched polymer. The dendritic polymer and the hyperbranched polymer each independently has a degree of branching of about 0.3-1, and each independently has a weight average molecular weight of greater than about 1000. The catalytic cracking process is beneficial to enhancing and accelerating the free radical cracking of petroleum hydrocarbon and promoting the regulation of cracking activity and product distribution; by using the process disclosed herein, the conversion of catalytic cracking can be improved, the yields of ethylene and propylene can be increased, and the yield of coke can be reduced.

Abstract: A process for preparing compounds of chitosan saccharified with aminosugar, adopts chitosan derivatives, aminosugar derivatives and anhydride derivatives as raw materials to synthesize target products. The process comprises: covalently bonding an anhydride derivative as a bonding arm to an aminosugar derivative, so as to form a monosaccharide derivative having an end group of carboxyl; and then covalently bonding the monosaccharide derivative having an end group of carboxyl to a primary amino group of a chitosan derivative via the carboxyl, so as to form a compound of chitosan saccharified with aminosugar.

Abstract: A process for preparing compounds of chitosan saccharified with aminosugar, adopts chitosan derivatives, aminosugar derivatives and anhydride derivatives as raw materials to synthesize target products. The process comprises: covalently bonding an anhydride derivative as a bonding arm to an aminosugar derivative, so as to form a monosaccharide derivative having an end group of carboxyl; and then covalently bonding the monosaccharide derivative having an end group of carboxyl to a primary amino group of a chitosan derivative via the carboxyl, so as to form a compound of chitosan saccharified with aminosugar.