08 August 2012, Volume 30 Issue 22

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  • HUANG Songping;ZHU Yazong
    . 2012, 30(22): 15-18.
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    The inventor's right of science and technology is common for the history of science, is also the common occurrence on the stage of today's world science. Therefore, it's necessary to provide a fair and feasible evaluation standard for inventor's right of science and technology in theory. This paper tries to put forward science and technology criteria accord with integrated principle of system theory in general, which will play an active role in the real evaluation of inventor's right of science and technology, especially for settling the debate of complicated inventor's right of science and technology. According to the overall evaluation criteria of inventor's right of science and technology, Tu You-you enjoys the inventor's right of artemisinine undoubtedly. Therefore, this paper expects to draw a full stop for the current inventor's right of artemisinine.
  • Articles
  • ZHOU Yi;LIU Zhenyi;QIAN Xinming;LI Hao;PAN Zhenxiang;ZOU Guifu
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    The air injection is an issue much studied and with a large amount of field practice experience, as it is an efficient way for oil recovery from the oil-gas reservoirs with low permeability. The flammable gas explosion should be considered during the process. In order to study the explosion scope and the explosion intensity, numerical simulations on the crude oil vapor explosion in the air injection pipeline under 30 MPa with different initial temperatures were conducted with the help of software AutoReaGas. The model is established according to an air injection pipe in an oilfield. The initial conditions are the typical parameters in the production process, such as the pressure 30MPa, the temperatures 20 ℃,45 ℃ and 90 ℃. The explosion temperature and the overpressure are analyzed as the two important parameters. It is found that after the explosion, the overpressure will reach 450 MPa and the temperature will reach 2400 K, which will do a great harm to the oil pipe and the Christmas Tree. The overpressure in the pipe is closely related to the initial temperature. The overpressure decreases when the initial temperature increases before the superposition of the explosive wave and the reflected wave, while the overpressure increases evidently when the initial temperature increases after the superposition area. However, the overpressure in the area more than 750m away will almost be zero. The initial temperature has little effect on the explosive temperature. When the initial pressure is 30 MPa, the temperature in the pipe will be back to the initial temperature in the area more than 600m away no matter how high the initial temperature is. It is concluded that only in the area filled with gas and the nearby area, the pressure and the temperature will rise after the explosion, the far away areas are little influenced.
  • LIU Gang;CHEN Chao;HAN Jinliang
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    The existing solid particle detection methods for the liquid-solid flow suffer from various degrees of defects. For this reason, the acoustic emission detection device for the liquid-solid two-phase flow is proposed and developed, and the indoor evaluation tests are carried out. Using the software developed by us, the information of sand concentration and size is extracted from tests under laboratory conditions. The results show that the power spectrum amplitude of the sand acoustic emission increases with the sand mass content under a fixed sand size, but decreases with the increase of the sand size under a fixed sand concentration.
  • ZHANG Wei;WU Zheng;GUO Xiangying
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    In the study of the aero-engine compressor blades, the blade is simplified as a rotating cantilever FGM plate with varying rotating speed. Based on the Reddy's high-order shear deformation theory and the von Karman type equations for the geometric nonlinearity, the nonlinear governing partial differential equations of motion are derived by using the Hamilton's principle. The aerodynamic load is determined by using the first-order piston theory. The Galerkin approach is used to transform the nonlinear partial differential governing equations of motion into a two-degree-of-freedom nonlinear system. The principal parametric resonance and the 1:1 internal resonance are considered. The asymptotic perturbation method is used to obtain a four-dimensional nonlinear averaged equation. The numerical method is used to find the nonlinear dynamic responses of the rotating cantilever FGM plate. It is found the rotating speed has an important influence on its nonlinear dynamic behavior. It is shown that, at different rotating speeds, there exist the chaotic, periodic and quasi-periodic motions for the rotating cantilever FGM plate.
  • ZHOU Yunshan;WANG Suzhen;ZHANG Jun;CAI Yuanchun
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    In view of the complicated structure of the Hybrid Electric Vehicle(HEV), a two-axle driving system is proposed. A traction coupled-HEV drive system for the vehicle is designed, making it a two-axle drive HEV. The vehicle can simply switch the operating modes. A two-axle drive HEV model is established with the aid of AVL-Cruise, and its performance indices, such as the maximum gradient, the acceleration time, the power and the fuel consumption, and the distribution of the engine's operating points, are obtained by simulation tests. The results show that the traction coupled-HEV drive system allows the engine and the motor work efficiently. Therefore, the fuel efficiency is improved, and the advantages in energy saving and emission reduction are significant.
  • ZHU Tong;XIE Chenjiang;WANG Qiang
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    Vehicle collision risk model is proposed for vehicle collision avoidance system in this paper. Probability attributions of collision risk and vehicle kinematical parameters were analyzed at first. Then the risk models based on probability computation for angle collision is established. Simulation evaluation was also implemented at many common scenarios employing micro simulation tool of Vissim. First of all, this paper divided the process of collision for car-following into two stages: leading vehicle decelerates and the following vehicle can not avoid the collision on the condition of it. On the basis of that, the probability of rear-end collision which used to express the risk of car-following was calculated using the method of total probability. What's more, a deceleration probability density function model was developed. In the analysis of the condition on which collision occur while leading vehicle decelerating, brake system response time and sticking coefficient were taken into account and this make the model forceful to reflect the real traffic situation. To evaluate performance of the new method, value of risk was calculated as a function of the data generated from Vissim. Simulation results indicate that the new approach is easer to reflex safety situation and more suitable for intersection collision avoidance system.
  • LI Xibing;LIAO Jiubo;ZHAO Guoyan;ZHOU Zilong;ZOU Yang
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    The dynamic loading due to blasting vibrations often leads to local instability of the highly-stressed tunnel and the rock burst during mining. Based on the elasticity and the stress wave theory, the mechanism of the instability and the crack development due to the dynamic vibrations in the highly-stressed tunnel are analyzed. In order to see why the highly-stressed tunnel in Yongshaba mine might be severely destroyed by dynamic vibrations, the numerical simulations of the highly-stressed tunnel under dynamic loading are carried out with the particle flow software PFC2D, and the effects of the disturbance stress wave intensity on the stress fields, the displacement fields and the crack fields in the surrounding rock are investigated by varying the peak value of the dynamic loading. The static and dynamic calculations are carried out, separately. The results show that the extents of the stress fields, the displacement fields and the crack fields in the surrounding rock under a dynamic disturbance will increase obviously as compared to the static calculation results. The higher the disturbance stress wave intensity, the more significant the dynamic disturbance influences on the stress, displacement and crack fields both in the roof and the floor of the tunnel will be. Several suggestions are made to avoid the instability and the subsidence of the highly-stressed tunnel induced by the dynamic disturbance.
  • LI Qiyue;SUN Li
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    The fracture toughness is the most important indicator in the rock fracture mechanics, which represents the ability to resist the crack propagation or the resistance needed to overcome new formations of crack surfaces. In this paper, based on the particle flow theory, the Particle Flow Code (PFC) model of rock with a pre-existing joint is constructed by using the parallel-bond model and the joint model. The failure process and the crack propagation path during the Brazilian disc(CSTBD) test are numerically simulated by using the particle flow code in two dimensions (PFC2D), and the fracture toughness of the rock model is measured based on the simulated test data and the energy balance. Comparisons between numerical and experimental results show a good agreement, which indicates the validity and practicality of this method.
  • ZHENG Yafeng;ZHANG Yongqiang
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    It is difficult to implement the device integration and linkage control in the safeguard control system. In order to do that, this paper proposes a method based on the ontology to integrate devices. A framework for the next generation intelligent control platform of the safeguard system is developed. A core business model is designed for the linkage system in the framework. In this framework, the ontology is used to describe the relationship among the device, the event and the command. A mapping file for the device, the event and the linkage action is build to deal with the linkage strategy. A signal receiver with a multi-queue buffer is provided in the event response model and this technology can handle the incident response of the linkage device. The corresponding algorithms are proposed in the paper. The system solves the unified access to heterogeneous systems (equipment) efficiently. Experimental results show that the entire system architecture has a good maintainability, and a high reliability in the real-time signal processing.
  • LI Birong;LI Yanbo
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    Based on a class of distributed delay systems, an adaptive sliding mode controller is proposed. According to the distributed delays, a suitable Lyapunov-Krasovskii functional is constructed, and the sufficient conditions of the asymptotical stability of the closed-loop systems are expressed in linear matrix inequalities. The adaptive sliding mode controller is constructed to satisfy the sliding mode reaching conditions. The delay-independent integral sliding mode is obtained and the sliding mode controller is simplified by the method. A numerical example is given to illustrate the validity of the proposed method.
  • Reviews
  • WANG Yan;ZHU Haolin;LI Qilu;ZHENG Qian;HUANG Juan
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    As a class of persistent, toxic, and bioaccumulated compounds, the chlorinated paraffins (CPs) can undergo a long-range atmospheric transport and be routinely detected in the various environment matrices. They are applied widely in industries as additives in lubricants and metal-working fluids, as flame retardants in plastics and sealants, and as plasticizers in polyvinyl chloride (PVC). The CPs, especially, the short-chain chlorinated paraffins (SCCPs), which are under review by the Stockholm Convention, represent a potential 'new' category of POPs and have attracted the global concern. China is the largest producer and exporter of the CPs, but the environmental studies on the CPs are extremely scarce. The sources, the levels, the distributions, and the fate of the CPs in different environmental media are reviewed in this paper, as well as the research prospect of the CPs in China.
  • LIU Ying;FENG Changgen;YANG Li
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    The non-azide gas generating composition is a hot research topic due to its many features, such as high nitrogen content, fast burning rate, good stability, non-toxicity, and green environmental protection. It is widely applied in airbag, spacecraft, fire fighting and other fields. In this paper, compared with the traditional azide gas generating composition, the properties of azole, azine, guanidine and azoic gas generating compositions are analyzed in detail; the progresses in the synthesis, the characterization and the application are reviewed; the formulas and characteristic parameters are discussed. It is found that the non-azide gas generating composition has not completely replaced the traditional azide gas generating composition, despite its superior properties in many aspects, because of factors like the high price,the excessive heat of combustion, and the high temperature. Therefore it is necessary to develop a more environment friendly,, non-toxic, effective, cheaper and practical non-azide gas generating composition.