Protected vegetable production made the traditional agriculture gradually get rid of the shackles of nature, broke the seasonal traditional agriculture and realized the anti season list of agricultural products. While...Protected vegetable production made the traditional agriculture gradually get rid of the shackles of nature, broke the seasonal traditional agriculture and realized the anti season list of agricultural products. While protected vegetables often encountered sudden disasters in production and were restricted with the conditions of low temperature and weak light. Aimed at the sudden disasters of protected vegetable production in Hebei Province,the countermeasures for disaster prevention and control were put forward from the aspects of variety selection, seedling treatment technology,grafting technique,cultivation and management,flower and fruit retention technology,application of exogenous substance,rational fertilization,transgenic technology and so on,in order to reduce production risks and cut loss,realize that protected vegetable production is safe,good-quality and efficient.展开更多
Vehicle crashworthiness simulation is the main component of the virtual auto-body design. One developing commercial vehicle was simulated on crashworthiness by the non-linear finite element method. The bumper crashwor...Vehicle crashworthiness simulation is the main component of the virtual auto-body design. One developing commercial vehicle was simulated on crashworthiness by the non-linear finite element method. The bumper crashworthiness at the speed of 8 km/h was analyzed and valuated. On the other hand, the deformation of the auto-body, the movement of the steering wheel and the dynamic responses of the occupant at the initial velocity of 50 km/h were studied. The results appear that the design of the vehicle could be improved on structure and material. Finally, the frontal longitudinal beam, the main energy-absorbing part of the auto-body, was optimized on structure. Simulation results also show that applying new material, such as high strength steel, and new manufacture techniques, such as tailor-welded blanks could improve the crashworthiness of the vehicle greatly.展开更多
This article analyzes the problem of computer network security, and design scheme of the network security system. The scheme uses advanced network security technologies, includes a complete set of physical isolation, ...This article analyzes the problem of computer network security, and design scheme of the network security system. The scheme uses advanced network security technologies, includes a complete set of physical isolation, desktop system security, virus protection, identity authentication, access control, information encryption, message integrity check, non-repudiation, security audit, intrusion detection, vulnerability scanning, electromagnetic leakage emission protection, security management and other security technology and management measures, the purpose is to establish a complete, multi-level three-dimensional, network security defense system.展开更多
文摘Protected vegetable production made the traditional agriculture gradually get rid of the shackles of nature, broke the seasonal traditional agriculture and realized the anti season list of agricultural products. While protected vegetables often encountered sudden disasters in production and were restricted with the conditions of low temperature and weak light. Aimed at the sudden disasters of protected vegetable production in Hebei Province,the countermeasures for disaster prevention and control were put forward from the aspects of variety selection, seedling treatment technology,grafting technique,cultivation and management,flower and fruit retention technology,application of exogenous substance,rational fertilization,transgenic technology and so on,in order to reduce production risks and cut loss,realize that protected vegetable production is safe,good-quality and efficient.
文摘Vehicle crashworthiness simulation is the main component of the virtual auto-body design. One developing commercial vehicle was simulated on crashworthiness by the non-linear finite element method. The bumper crashworthiness at the speed of 8 km/h was analyzed and valuated. On the other hand, the deformation of the auto-body, the movement of the steering wheel and the dynamic responses of the occupant at the initial velocity of 50 km/h were studied. The results appear that the design of the vehicle could be improved on structure and material. Finally, the frontal longitudinal beam, the main energy-absorbing part of the auto-body, was optimized on structure. Simulation results also show that applying new material, such as high strength steel, and new manufacture techniques, such as tailor-welded blanks could improve the crashworthiness of the vehicle greatly.
文摘This article analyzes the problem of computer network security, and design scheme of the network security system. The scheme uses advanced network security technologies, includes a complete set of physical isolation, desktop system security, virus protection, identity authentication, access control, information encryption, message integrity check, non-repudiation, security audit, intrusion detection, vulnerability scanning, electromagnetic leakage emission protection, security management and other security technology and management measures, the purpose is to establish a complete, multi-level three-dimensional, network security defense system.
