Abstract: A preparation method of a high-rate foamed polylactic acid (PLA) sheet includes first-stage extrusion, second-stage extrusion, and foamed sheet extrusion. The method requires the following raw materials in parts by mass: 88 to 94 parts of PLA, 1 to 2 parts of a nucleating agent, 2 to 5 parts of a foaming agent, and 2 to 5 parts of an additive. The new method effectively solves the problems of low foaming rate, low strength, and the like in the industrial production using carbon dioxide, and a prepared PLA sheet with high foaming rate and excellent surface performance can be used in the fields of food packaging, disposable fully-degradable lunch boxes, and the like.

Abstract: Disclosed is a composite nano-agent for combating drug-fast bacteria and a preparation method thereof. The solution comprises several steps of operation that a silver salt is reduced into silver nanoparticles; then, phosphatidylcholine (PC) and cholesterol are mixed and added into water, and ultrasonic treatment is carried out to form liposomes; the silver nanoparticles and the liposomes are then mixed and an ultrasonic processor is used to uniformly mix a mixture by adding polyethylene glycol (PEG); an anti-bacterial experiment is carried out on the prepared reagent to determine a sterilization effect and a minimal inhibitory concentration (MIC) thereof.

Abstract: Disclosed are gene engineering bacteria for producing L-arginine and a construction method and an application of the gene engineering bacteria. According to the method, genes encoding a carbamoyl phosphate synthetase and a gene encoding an L-arginine biosynthesis pathway enzyme are integrated into Escherichia coli; the present invention has analyzed and reconstructed the arginine synthetic pathway and the metabolic flow related to arginine in the entire amino acid metabolic network in E. coli and finally obtained a genetically engineered bacterial strain which has a clear genetic background, carries no plasmids, undergoes no mutagenesis and is capable of stably and efficiently producing L-arginine.

Abstract: A method for directly preparing a foamed polylactic acid (PLA) product from a PLA melt includes PLA melt preparation, feeding, and two-stage extrusion. In the two-stage extrusion, a pressure at an outlet of a first-stage twin-screw extruder is 15 MPa to 17 MPa, a PLA melt is fed at a rate of 250 kg/h, a foaming additive is fed at a rate of 7.5 kg/h to 10 kg/h, and a foaming gas is fed at a rate of 2.8 L/h to 7.5 L/h. The method can ensure both foamability and quality of a material and reduce more than ? of energy consumption; and an obtained product has an adjustable foaming rate of 3 to 25, a crystallinity of 40.3% to 48.5%, a tensile strength of 8.7 MPa to 19.6 MPa, and an apparent density of 0.05 g/cm3 to 0.4 g/cm3.

Abstract: A preparation method of a high-rate foamed polylactic acid (PLA) sheet includes first-stage extrusion, second-stage extrusion, and foamed sheet extrusion. The method requires the following raw materials in parts by mass: 88 to 94 parts of PLA, 1 to 2 parts of a nucleating agent, 2 to 5 parts of a foaming agent, and 2 to 5 parts of an additive. The new method effectively solves the problems of low foaming rate, low strength, and the like in the industrial production using carbon dioxide, and a prepared PLA sheet with high foaming rate and excellent surface performance can be used in the fields of food packaging, disposable fully-degradable lunch boxes, and the like.

Abstract: A new, facile, low cost and easy-to-operate method of forming and immobilizing metal nanoparticles on substrates is invented. The method comprises steps of chemical modification of the substrates with chemical linkers, chelation of the metal ions to the modified substrates, the washing of the unbound metal ions and in-situ reduction of the metal ions to produce metal nanoparticles on the substrates with/without the finishing treatment of the metal nanoparticles functionalized substrates with minimum particles aggregations. The metal nanoparticles functionalized substrates generated by the method have wide applications, for example, as anti-microbial agents. The metal nanoparticles are strongly bonded to the substrates, resulting in low metal leaching to the environment.

Abstract: A method for upgrading software or contents in a terminal device based on digital TV data broadcasting is provided. The method comprises steps of uploading an upgrading file or content file to an access gateway by a service provider via a data broadcasting system; transmitting the upgrading file or content file to the terminal device in a broadcast mode by the data broadcasting system; and receiving the transmitted upgrading file or content file by the terminal device. The method further comprises a step of determining whether the received upgrading file or content file is of a higher version than that of a currently used software file or content file of the terminal device; and if yes, upgrading the currently used software file or content file. The method according to the present invention decreases maintenance cost of the terminal device, facilitates upgrading system in time, maintains copyright benefit of the service provider, and is convenient for the user to upgrade his terminal device.

Abstract: This invention provides a method for multi-tasking on a media player in a time-slice-circular manner. The method comprises the step of: dividing each of different functions of the media player to a plurality of tasks by a controller unit; setting a priority to each of the tasks by the controller unit; checking the priority of said each of the tasks, and changing a state of a task from “READY” to “EXECUTING” according to the priority of the task by the controller unit; and executing the tasks alternately by using time slices associated therewith by the controller unit. Since all the tasks are executed within a short time, from the user's point of view, all the tasks are executed simultaneously. Thus, multi-tasking on the media player is achieved.