Jul 2024, Volume 9 Issue 12
    

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  • Wang Huating,Feng Junweng,Gao Peng ,Wang Jian
    2007, 9(12): 4-9.

    How to use experience and test result to make the best choice is a decision problem for a electric power company when deciding to build a reactor,  and valuation networks is a new method for representing and solving Bayesian decision problems. This article used Valuation Networks to analyze the reactor problem of a given company,  which valuation network representing and solving process is demonstrated in detail.

  • Zhang Fuqin,Bian Gangyue,Bian Siying
    2007, 9(12): 10-15.

    In view of the peak emergence of world oil and the prediction of China's energy demand and supply, the paper proposes that the development of China's oil industry should be based on domestic resources, which includes enhancing exploration and development of domestic oil-gas resources, building the conservation-minded society, realizing the multi-source strategy in energy development, etc. Meanwhile, great importance should be attached to exploiting overseas oil-gas resources and establishing the strategic reserves system for oil.

  • Li Xuejun,Zhang Meiyang,Chu Fulei
    2007, 9(12): 16-20.

    Because of the influence of rotary kiln supporting wheel's deflection on the contact area's contact stress,  according to Hertz contact theory,  the relative among deflection angle,  the maximum contact stress and maximum contact stress ratio when supporting wheel is under parallel and deflective are derived.  Furthermore,  with the finite element method,  the contact problems when supporting wheel is under parallel and the maximum deflection angle state are solved.  Distribution of supporting parts'maximum contact stress and the equivalent stress and strain are obtained,  and the dangerous and damageable place is learned.  These analysis conclusions can provide effective theoretic guidance for rotary kiln axial adjusting and controlling.

  • Fu Qiang,Zhang Heping,Zhu Wuba,Xie Qiyuan
    2007, 9(12): 21-25.

    This paper makes a calculation of the smoke evacuation volume in a certain Olympic gymnasium by using the smoke control formula from NFPA92B,  and makes an optimization design of the smoke evacuation and ventilation system by using the Computational Fluid Dynamics (CFD) stimulation software.  It also discusses the inner relationship among the mechanical smoke evacuation,  the mechanical ventilation and natural ventilation as well as the influence of the mechanical ventilation volume on the smoke evacuation system in the Olympic gymnasium,  which provides the theoretical basis for the optimization design of the smoke evacuation and ventilation system in the Olympic gymnasium.

  • Wang Shoudong,Shen Yongming,Jiang Hengzhi
    2007, 9(12): 26-30.

    Firstly,  based on node equation method,  a water distribution pipeline network steady flow mathematical model is established and is solved by using the Newton iteration method.  Secondly,  the mathematic model for transient flow set up by characteristic method can be used to forecast the harmful water hammer occurring in operation of the system,  and to find the possible occurrence of the maximum (minimum) hydraulic pressure and their corresponding happened place.  Sample shows that they are reliable models which have excellent computing efficiency and high order.  The results are that these models can be applied to hydraulic balance calculation for city's water distribution pipeline network and provide the theoretic basis for designer to adopt measures preventing from water hammer.

  • Hu Dongsheng,Zhang Huajing,Xu Bing,Tian Xinhong and Zhang Guowei
    2007, 9(12): 31-38.
    By combining the comprehensive data analysis results and the earth satellite remote sensing images explanation in East Asia region, the paper finely studied Korea massifs, the typical structure district in global construct fields. The basic structure pattern of Korean peninsula region is identified in detail. Its basic types mainly include the wreath form structures (and the radiation structure), the trailing structures, the conjugate structures, the rhombus structures, the dominoes structures, etc. The evolving process of the structual geology environment and the earth dynamic mechanism are macroscopically elaborated. Before the post Palaeozoic era, it was formed by sticking weld of three different tectonic plates (North China tectonic plate, Yangzi tectonic plate, South China tectonic plate)in eastern China. After swell up landing in the Mesozoic era, it experienced the influence of the three periods of the construct movement (Songnim orogeny, Daebo orogeny, Bulgugsa orogeny), and the Yeonil orogeny occurred in the Cainozoic era. The basic structure pattern of Korea massifs was influenced by the side direction level movement of the Chinese edge sea basin and Japanese sea basin. Its trajectory of the structural principal stress extended in the north east - south west direction. The trajectory of modern principal stress spreads along the north west west - south east east direction, Full attention should be paid to the modern geological function and the enviromental effect function.
  • Xu Liang,Zhang Heping and Wan Yutian
    2007, 9(12): 39-43.
    Cone calorimeter was employed to study the ignitability of common thermoplastics, and the numerical and linear regression methods were used to deduce the ignition model for intermediate thermal thickness. Then the ignition time data was analyzed with the deduced model to get the critical heat flux, ignition temperature and thermal properties for the studied materials.The results showed that the deduced critical heat flux and ignition temperatures agreed well with those from literature,which indicated that the model is applicable.
  • Liu Dabin,Han Wenba,Cai Bingqing and Han Xiaodong
    2007, 9(12): 44-52.
    In this paper, a comprehensive analysis and comparison is fulfilled between the four classical intensity theories, Mohr´s intensity and a new balance particle intensity theories. A comparative study is developed between the test results of pulling or pressing in single direction and double directions. It is shown that the new balance particle intensity theory is more coincident with the test results than other five intensity theory. Especially, the intensity formula of pulling (bending)shear (torsion) deduced from the particle balance theory can easy explain the phenomena that pulling makes the destructions easy and suppression makes the destruction hard to achieve. This phenomenon cannot be well explained by the four classical intensity theories and Mohr’s intensity theory. The particle balance intensity theory clarifies the misunderstanding that if the equivalent stress is zero, the third and fourth intensity theory regard that the beam under three or fourdirections cannot be destroyed whatever the force is. The balance particle intensity theory figures out a contrary conclusion with the third intensity theory and fourth intensity theory.
  • Yuan Lingshuang,Liu Meng and Wang Jun
    2007, 9(12): 53-56.
    Air cooling unit and electrical heater are used to simulate temperature with wide range on Altitude Simulation Test Facility (ASTF) for reciprocating aeroengine, it is difficult to achieve controlling accurately. In this paper simulated temperature is divided into three segments of low, normal and high temperature and distinct strategies are applied to regulate temperature respectively. Based on the dynamical analysis and modeling of temperature change, research is performed on the regulating process for ASTF temperature system, and simulation results show that these strategies could satisfy the demand for speed and precision of temperature controlling. For the inlet temperature of airflow into reciprocating aeroengine through turbocharger, the mathematic relationship for heat transfer between turbocharger and intercooler is built.Simulating calculation on an example for engine in steady state at different altitude is carried out. The results present that calculation trend is consistent with the fact.
  • Chen Shouke and Wei Zhuobin
    2007, 9(12): 57-62.

    During the operation process of largescale public project, financing risk is a main factor to the success of project. Based on the analysis of composition of finance and its connotation, using quantitative mode, this paper discussed the financing risk of large public project operation from three aspects: finance scale, construction time and return on the investment. Finally, it gave an illustration to prove the right of mathematic mode and put forward proposals for the increase of profit.

  • Tang Jun,Shen Yongming and Qiu Dahong
    2007, 9(12): 63-68.
    In coastal and offshore areas, the breakingwaveinduced currents induced as waves propagate obliquely to coastal zone are important environmental factors, which play important roles on movement and distribution of pollutants in these zones. Based on parabolic mild slope equation for wave propagating in mild slope zones, the nearshore currents model, as well as model of pollutants movement in nearshore water waves and currents, pollutants movement processes in water waves and longshore currents, which are induced by inclined incident coastal water waves, were numerical simulated, and the numerical results were validated and analyzed.
  • Huang Liangpei,Yin Xiyun and Yue Wenhui
    2007, 9(12): 69-74.
    The mechanical equipment faults result from parts failure in the period of service time. Due to reassembly and maintenance, the reliability model for mechanical equipment is broken, so it is necessary to research and estimate the safety reliability of mechanical system. Based on the timetofailure density function of parts, the mechanical system reliability model is constructed to track the change course of age structure of part population for the mechanical systems that are reassembled and maintained. By means of simulation of the system reliability model, concerned parameters with mechanical systems service life are defined.The paper discusses how the timetofailure density function hase influence on the service life for mechanical systems undergoing reassembly and maintenance. It is significant for estimating reliability and failure rate of systems and establishing reasonable maintenance policies.
  • Cao Guangrong,Hu Ya’an and Gao Xiong
    2007, 9(12): 75-80.
    This paper discusses the fluctuating character of the water in Chamber 1 when No.2 chamber head is operating as the first one under the four-steps shiplock operating mode, expatiates the forming principle of the fluctuation, analyzes the impact on the water fluctuation in Chamber 1 when No.2 chamber head is operating as the first chamber head, puts forward the valve opening pattern satisfying the safety demand when Chamber 1 is waiting, and tests the berthing condition of the ships in Chamber 1 by the experiment with real ships. The facts show that during the course of the Three-Gorges shiplock being fulfilled under the four-steps shiplock operating mode, the ways transferring the ships downriver from near frusta to chamber 1 can increase passing ability of about three ships per day, producing huge navigation benefit.
  • Chen Liquan,Hu Aiqun,Xu Qing and Yang Xiaohui
    2007, 9(12): 81-85.

    A novel endtoend data transmission scheme based on OFDM mechanism with good robustness against the RPE-LTP vocoder in GSM voice channel is proposed. According to the character of RPE-LTP vocoder, data are modulated to orthogonal lowfrequency sinusoidal carrier. In OFDM, the modulation is done by IFFT and the modulated signals are conformed to the time and frequency characters of RPELTP vocoder. The results of simulation show that the transmission bit rate of the proposed scheme reaches 2.4 kb/s,and the bit error rate of the scheme is lower than 0.3 %. This scheme provides a new approach for realtime secure voice data transmission over GSM system.

  • Zhang Binglei,Xu Jinliang and Xiao Zejun
    2007, 9(12): 86-93.
    Pressure drops of flow boiling in a single microchannel having low aspect ratio were studied with effects of the inlet temperature,mass flux,heat flux and the inclined angle using methanol as working fluid. The present experimental data were compared with the predictions of the homogeneous flow model and separated flow model respectively. The comparison indicates that the homogeneous flow model cannot predict the twophase pressure drop well except using the twophase viscosity model of the Dukler correlation. With the existing correlations for parameter C in LockhartMartinelli correlation such as Chisholm,Lee and Lee,Mishima,Qu and Mudawar , separated flow model also failed to predict the twophase pressure drop in the microchannel of this study . The experimental data in this work show that the interaction between vapor phase and liquid phase is decreased with the increasing quality when the quality reach a certain value , accordingly there needs a correlation for C which decreased with the decreasing mass flux .A new correlation to predict the twophase flow pressure drop in microchannels was developed in the form of the LockhartMartinelli correlation .It includes the effect of the hydraulic diameter and the effect of mass flux on the twophase flow pressure drop in microchannels .The new correlation developed in this study predicted the experimental data within a mean absolute error of 16.9%.
  • Sun Xueyong
    2007, 9(12): 94-96.
    This paper discusses the hardware structure and working process of the embedded Internetconnected platform, which regards S3C2410 as kernel and SIM100-E as GPRS communication module. Then the software hierarchy is described and the realization of PPP dialup software package based on this platform is explained in detail.