Abstract: This disclosure provides a method, apparatus and computer-readable storage medium for visual teaching. The visual teaching method includes establishing a classroom, arranging the classroom based on the real geometric layout of at least one teaching device in the classroom, and conducting the course in the classroom based on the arranged classroom, wherein the classroom comprises at least one user smart terminal, at least one teaching device and at least one of a management smart terminal and a server, at least one teaching device and/or at least one user smart terminal being communicatively connected to at least one of the management smart terminal and the server operating the classroom, each of the user smart terminals operating at least one corresponding teaching device and obtaining the status of the corresponding teaching devices. The visual teaching solution provides a course-oriented and student-oriented visual teaching environment by combining the courses, teaching devices and students.

Abstract: This disclosure provides a method, apparatus and computer-readable storage medium for visual teaching. The visual teaching method includes establishing a classroom, arranging the classroom based on the real geometric layout of at least one teaching device in the classroom, and conducting the course in the classroom based on the arranged classroom, wherein the classroom comprises at least one user smart terminal, at least one teaching device and at least one of a management smart terminal and a server, at least one teaching device and/or at least one user smart terminal being communicatively connected to at least one of the management smart terminal and the server operating the classroom, each of the user smart terminals operating at least one corresponding teaching device and obtaining the status of the corresponding teaching devices. The visual teaching solution provides a course-oriented and student-oriented visual teaching environment by combining the courses, teaching devices and students.

Abstract: The present invention disclosed N-acetyl amino acid ester derivatives of betulin and the preparation method thereof, the method comprising the steps that in the presence of an alkaline substance, a catalyst and a racemization-inhibitor, the carboxyl group of N-acetyl amino acid is activated by a coupling agent; and then the activated N-acetyl amino acid is reacted with betulin via esterification reaction to obtain the N-acetyl amino acid ester derivative of betulin. The present invention provided a simple synthesis method to synthesize the N-acetyl amino acid ester derivatives of betulin by using betulin as a precursor compound and modifying the molecular structure of betulin. Such structural modification of betulin significantly enhances the anti-tumor activity of the betulin derivatives and therefore has important values.

Abstract: The present invention disclosed N-acetyl amino acid ester derivatives of betulin and the preparation method thereof, the method comprising the steps that in the presence of an alkaline substance, a catalyst and a racemization-inhibitor, the carboxyl group of N-acetyl amino acid is activated by a coupling agent; and then the activated N-acetyl amino acid is reacted with betulin via esterification reaction to obtain the N-acetyl amino acid ester derivative of betulin. The present invention provided a simple synthesis method to synthesize the N-acetyl amino acid ester derivatives of betulin by using betulin as a precursor compound and modifying the molecular structure of betulin. Such structural modification of betulin significantly enhances the anti-tumor activity of the betulin derivatives and therefore has important values.