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: The proposed invention discloses an authentication scheme for avoiding emergency vehicles. Emergency vehicles send accident rescue route information and authentication message requests to the nearest roadside unit (RSU). Upon receiving the message, the RSU verifies the legitimacy of the vehicle's identity and generates shared secret values, which are encrypted and sent to the emergency vehicle. Simultaneously, the RSU forwards the avoidance route message, partial vehicle information, and the shared secret values to the second RSU along the rescue route. When the emergency vehicle reaches the second RSU, it sends a request for authentication to the RSU. Upon successful authentication, new shared secret values are generated, encrypted, and sent to the emergency vehicle. Simultaneously, the avoidance route message, partial vehicle information, and the newly generated shared secret values are passed on to the next RSU along the rescue route.

Abstract: The invention belongs to the field of computer security and discloses a blockchain-based anonymous authentication method for the Internet of Vehicles across trusted authorities, including registering the vehicle (with onboard unit) and roadside unit in their respective trusted authorities. When the vehicle enters different trusted authority domains, both the onboard unit and roadside unit generate corresponding authentication parameters and transmit them to the consortium blockchain of the Internet of Vehicles for verification and signature, obtaining authenticated data signed by the consortium blockchain. The onboard unit and roadside unit receive and verify the authenticated data, and upon successful verification, the onboard unit calculates a session key. The onboard unit uses the session key to sequentially transmit data with the roadside unit and the consortium blockchain.

Abstract: The proposed invention discloses an authentication method for emergency vehicles to quickly pass through traffic lights, which relates to the field of information security technology. The method designs a traffic light service request message propagation and handover authentication structure by considering that traffic lights are located in different roadside unit domains, enabling emergency vehicles to quickly pass through multiple traffic lights until they reach the intended destination. By introducing elliptic curve encryption operations on critical parameters during the authentication process, the security of the entire authentication process is enhanced, effectively resisting various known attacks. The adoption of elliptic curve Diffie-Hellman secret exchange values for authentication ensures the legitimacy of identities. Vehicles employ a dynamic anonymity strategy to protect privacy, avoiding the transmission of identity-related information over public channels and achieving privacy protection.

Abstract: The invention discloses a cross trusted authority identity authentication and message publishing method based on redactable blockchain, adopts a redactable blockchain based on chameleon hash function to replace the traditional blockchain, and the trusted authority can use the private key of the chameleon hash function to edit the block content on the blockchain, so that only legal, valid and timely information is stored on the blockchain. In addition, the trusted authority can also edit the vehicle authentication information stored on the blockchain, easily updating the vehicle information credentials or revoking the information credentials of illegal vehicles. In the process of authentication and key negotiation, cryptography tools are used to ensure the confidentiality, integrity and availability of messages, and can effectively resist various known attacks.

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: At least one aspect of the present disclosure relates to a two-dimensional mineral membrane including a first phyllosilicate material and a second phyllosilicate material crosslinked with the first phyllosilicate material, where a surface of at least one of the first phyllosilicate material or the second phyllosilicate material includes at least one functional group. Another aspect of the present disclosure relates to a method of producing a two-dimensional mineral membrane. The method includes providing a first phyllosilicate material and a second phyllosilicate material, exfoliating a mixture of the first phyllosilicate material and the second phyllosilicate material into a plurality of flakes, crosslinking the first phyllosilicate material with the second phyllosilicate material, functionalizing a surface of at least one of the first phyllosilicate material or the second phyllosilicate material, and restacking the plurality of flakes to form a membrane.

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.