Abstract: The present invention discloses a synthesis method of lactide by confinement effect catalysis of crystalline porous polymer material, wherein the method comprising: (I) synthesis of catalyst; (II) synthesis of lactide by confinement effect catalysis; and (III) purification of lactide. In the present invention, a yield of L-lactide by catalysis of L-lactic acid by crystalline polymers is as high as 85.6%, which is 10% higher than the yield of lactide by H-? molecular sieve reported in documents currently available; it is easy to prepare the crystalline porous polymer material catalyst, which is environmental friendly, has a high yield and is recyclable, for consecutive 7 times the catalysis yield is maintained to be higher than 70%, and catalysis yield conservation rate is far higher than catalysis effects of catalysts reported in documents currently available.

Abstract: The photovoltaic cell includes a silicon substrate, a first passivation layer, a second passivation layer, at least one silicon oxynitride layer, and at least one silicon nitride layer. The second passivation layer includes a first silicon oxide layer and at least one aluminum oxide layer, a ratio of the number of oxide atoms to the number of aluminum atoms in the at least one aluminum oxide layer is greater than 0.8 and less than 1.6. The number of silicon atoms is greater than the number of oxygen atoms in the at least one silicon oxynitride layer and the number of oxygen atoms is greater than the number of nitrogen atoms in the at least one silicon oxynitride layer. A ratio of the number of silicon atoms to the number of nitrogen atoms in the at least one silicon nitride layer is greater than 1 and less than 4.

Abstract: A multipath suppression method based on a steepest descent method includes stripping, according to carrier Doppler shift information fed back by a phase-locked loop, a carrier from an intermediate-frequency signal input into a tracking loop; constructing, on the basis of the autocorrelation characteristics of a ranging code, a quadratic cost function related to a measurement deviation of the ranging code, the cost function being not affected by a multipath signal; and finally, designing a new tracking loop of the ranging code according to the quadratic cost function and the principle of the steepest descent method, such that the loop has a multipath suppression function without increasing the computational burden. Compared with a narrow-distance correlation method, the current method reduces computing resources by ?, the design and adjustment of parameters are simple and feasible, a multipath suppression effect is superior, and a high engineering application value is obtained.

Abstract: A multipath suppression method based on a steepest descent method includes stripping, according to carrier Doppler shift information fed back by a phase-locked loop, a carrier from an intermediate-frequency signal input into a tracking loop; constructing, on the basis of the autocorrelation characteristics of a ranging code, a quadratic cost function related to a measurement deviation of the ranging code, the cost function being not affected by a multipath signal; and finally, designing a new tracking loop of the ranging code according to the quadratic cost function and the principle of the steepest descent method, such that the loop has a multipath suppression function without increasing the computational burden. Compared with a narrow-distance correlation method, the current method reduces computing resources by ?, the design and adjustment of parameters are simple and feasible, a multipath suppression effect is superior, and a high engineering application value is obtained.

Abstract: The present invention discloses a synthesis method of lactide by confinement effect catalysis of crystalline porous polymer material, wherein the method comprising: (I) synthesis of catalyst; (II) synthesis of lactide by confinement effect catalysis; and (III) purification of lactide. In the present invention, a yield of L-lactide by catalysis of L-lactic acid by crystalline polymers is as high as 85.6%, which is 10% higher than the yield of lactide by H-? molecular sieve reported in documents currently available; it is easy to prepare the crystalline porous polymer material catalyst, which is environmental friendly, has a high yield and is recyclable, for consecutive 7 times the catalysis yield is maintained to be higher than 70%, and catalysis yield conservation rate is far higher than catalysis effects of catalysts reported in documents currently available.