Search

In this paper, the nonlinear synchronization scheme is proposed for secure communication via a new Lorenz chaos system. Based on the time scale transformation, a new chaotic circuit is designed. Then the nonlinear synchronization is realized by using nonlinear feedback control method. The experimental results show that the nonlinear synchronization method is effective, and can realize the nonlinear synchronization of the drive circuit and the response circuit composed by the chaotic system, and apply it to the secure communication, which can make the receiving and sending information consistent, and make the secure communication system more confidential.

This paper introduces an automatic calibrated pure electric (EV) mode of automatic switching based on bus road conditions. The entire vehicular control system collects bus road spectra using specific methods, identifies if the direction of the bus is along the predetermined bus lane, and records the positions where the driver manually switches the model, to finally implement an automatic EV switchover method function along bus lane roads. This method enables the flexible calibration of roads where EV mode is to be used, and implements automatic switching to avoid running on uphill roads in EV mode in order to decrease the labor intensity of drivers.

The existing network platform can not meet the new launch vehicle launch costs, and there is the need for high reliability storage and application of massive data. A scheme of measuring and controlling network system based on cloud platform is put forward. The centralized management of system resources is realized. Enhanced resource utilization and system scalability, and reduced the development cost of the system. Through the centralized storage and management of rocket data, as well as the powerful computing and storage capacity of cloud computing, promote the gathering, integration and sharing of data resources. Enhance the security of the network system.

The minimum value of the hydrogen source capacity, based on the demand for a hydrogen consumption rate and a working life, calculated from the conversion of ion pump current and the test of hydrogen consumption experimental equipment, is about 25.4 atm·L Considering the redundancy, it should be actually equal to about 40 atm·L, and the marginal coefficient amounts to 1.6. Compared with the storage of hydrogen by high-pressure gas technology, the storage by solid alloy in the same volume decreases the pressure by almost one order of magnitude. The reliability of hydrogen source is improved by the technology of metal detection, bulge test and mass spectrometer leak detection. According to the tests of hydrogen source bleed platform and assessment of long lifetime, a mathematical model of hydrogen source is built up, predicting the lifetime of hydrogen source to more than 12 years. The results indicate that the hydrogen source satisfies the requirements for security, reliability and lifetime of the space passive hydrogen maser.

For the passive hydrogen maser (PHM) having excellent frequency stability performance and lower frequency drift, it has been chosen as the one of atomic clock in the Beidou navigation satellite system. Beijing Institute of Radio Metrology and Measurement (BIRMM) is responsible for the whole equipment, including Physics Package (PP) and Electronic Package (EP). A Flight Model (FM) has already launched with satellite. This paper gives the results of PHM physics parameters and measurements of PHM. At last, the paper presents the results of PHM phase comparison on board, and gets negligible drift relative to rubidium clock.

From the start of the technical background, research purpose and design ideas, introduces the intelligent concrete compressive strength tester(patent product) structure and its detection method. And through the concrete examples, expounds further the detection method (patent technology)automation, reduce or avoid the damage to concrete structure, reduce the influence of various factors, so as to improve the accuracy of detection, the scene could be widely used in concrete structure construction, the compressive strength of railway, traffic, water transport, port engineering industry detection, and has the advantages of environmental protection, economy etc.

In this paper, analysis and optimization of test, calculation, through screening, to determine the new anti sulfate erosion of concrete formulation of the source, the basis and the amount of. After verification by experiment, the model design of each performance index, high resistance to sulfate erosion of concrete mixture after concrete hardening of concrete compressive strength, frost resistance, impermeability test results can meet the technical requirements, and can be widely applied to the concentration of sulfate erosion, over 8000 mg/L compressive strength at C20 ~ C40, F200, anti frost resistance grade permeability grade W6 concrete engineering.

Plugging technology near launcher & receiver, which is used to replace the section of pipeline near launcher & receiver or block valve, refers to put plugging head into the specified location from launcher & receiver by the push rod to complete pipeline sealing operation. The sealing rubber tube structure is the key component of the plugs near launcher & receiver, which relates to the sealing reliability and operation safety. This paper has established the mathematical model between the contact pressure and the extrusion force of the sealing rubber tube, and concluded the functional relationship between the axial compression force of rubber tube and radial deformation. We use Matlab software to simulate the changing law of the contact pressure and the diameter of the rubber tube, and get the design size of the sealing rubber tube. We also analyze the sealing rubber material parameters, which affects the performance of dynamic sealing, by the finite element. The research provides the necessary theoretical basis and technical reference for the near launcher & receiver plugging operation.