18 June 2014, Volume 32 Issue 17

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  • ZHENG Xiongbo, ZHANG Liang, JIANG Jin, MA Yong
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    Ocean wave energy is a clean marine renewable energy, which has received widespread attention. A wave energy device with swing arms and floaters was designed and produced. To study the movement and energy conversion performance of the device, model experiment was carried out in the tank. The device was composed of two floaters, two swing arms, mechanical transmission device and generators. The device was fixed on a trailer. Through experiments under different working conditions, the vertical acceleration of floaters and output voltage of the generator were measured. Finally, the influence of wave height and period on floaters' movement was analyzed, and the wave energy conversion efficiency was computed. Experimental results show that under action of the wave, the heaving motion performance is satisfactory, and the device has high energy conversion efficiency.
  • XIONG Jian, LIANG Lixi, LIU Xiangjun, ZHANG Andong
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    Methane adsorption properties of shale gas reservoirs are the premise and foundation for shale gas reservoir development, and have an important influence on resource forecast and productivity evaluation. Based on the measured isotherm data under different temperature and adsorption potential theory, the ε-ω adsorption characteristic curve can be drawn and is described by analyzing and treating the isotherm data. The result shows that the ε-ω adsorption characteristic curve of shale to CH4 is unique and independent of temperature, which can forecast methane adsorption at different temperature and obtain the adsorption isotherm of shale to CH4. The density of adsorbed phase plays an important role in forecasting the methane adsorption by the ε-ω adsorption characteristic curve, which is relevant to the accuracy of methane adsorption forecast. Therefore, the calculation method of the density of adsorbed phase needs further studies.
  • WANG Xinmin, LIU Jixiang, CHEN Qiusong, XIAO Chongchun, WAN Xiaoheng
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    Back-propagation neural network was used to optimize the flocculating sedimentation parameters. To get the best network mode, some learning and training samples were established by the numbered orthogonal blasting tests. In the process of establishing the network mode, the tailings concentration, flocculant consumption and flocculant concentration were used as the input data, the sedimentation speed and limiting concentration were confirmed to be the synthesized output data. Comparison of the influences of hidden layer nodes on model training process and prediction accuracy indicates that the optimal hidden layer node was 9. By entering the refined flocculating sedimentation parameters into the prediction model, optimal samples are searched and the optimal parameters show that the flocculating agent consumption is 4.5 g/t, flocculating concentration is 0.11% and tailings concentration is 15%. Compared with that of the experimental results, the relative error of the prediction results can be controlled at about 5%. The application indicates this mode has relatively high accuracy, providing a new method to optimize the flocculating sedimentation parameters.
  • TANG Shihui
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    For many uncertainty factors in the roadway support schemes evaluation, considering the actual engineering status, 14 key indicators are selected and the uncertainty problems are solved by quantitative and qualitative evaluations, respectively. The entropy theory is used to calculate the weights of the indicators, and the advantages and disadvantages of a support scheme are evaluated according to the credible degree recognition criteria. An evaluation system for roadway support schemes is finally set up based on unascertained theory using VC++ language. Furthermore, this evaluation system is used to evaluate roadway support schemes of soft and fractured medium in a gold mine. The result shows that the optimized support scheme is the forepoling bolt and U-formed arched falsework. This study indicates that the evaluation system is reasonable and can provide a basis for the support design and production management of similar projects.
  • LÜ Youliang, CAO Siyuan, LÜ Yumin
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    Based on the identification and genesis analysis of paleo- karstification, paleo- geomorphology of the Lungu area is reconstructed by using residual formation thickness method, geomorphologic method and impression method. Karst upland margin, karst slope, and karst valley of Ordovician carbonates in the Lungu area are marked and eight types of micro- geomorphology units are identified. The relationships between karst morphology and characteristics of carbonate reservoirs are studied in different subareas. The results show that all the karst zones develop fractures and vugs, but reservoir types are different in micro-geomorphology units. Karst upland and slope in the superficial karst zone mainly develop fracture-vug-type and fracture type reservoirs, the vertical karst zone develops fractures and vugs, and run-off karst zone is apt to develop vugs and caverns.
  • ZHAO Dongmei, TONG Cong
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    The particle gravitational classification process is one of the important factors affecting the centrifugal classification performance of a classifier. To understand the particle motion characters in the gravitational classification zone of the classifier, an SLK5500 classifier is chosen as the object, and particle motion equations are built in the y direction and x direction by analyzing the action forces on the particle. And theoretical analysis is made to explore particle characters in the y and x directions on the basis of the particle motion equations. According to the computational fluid dynamics theory, the changing rules of gas velocities in the y and x directions of the gravitational classification zone are investigated, and particle trajectories of different diameters are studied. The theoretical analysis and simulation result show that in the gravitational classification zone, the gas velocity increases progressively in the y direction, where particle motion is a variable acceleration motion with an increasing acceleration; the gas velocity decreases from the return cone near wall terminal to the far wall, and the particle motion in the x direction is a variable acceleration motion with a decreasing acceleration. This research has provided a reference and data for the classifier structure design.
  • GUO Ruiping, YANG Chunlin, WANG Bo, ZHANG Qiong, CHEN Haiying, ZHANG Chunming, LIU Fudong
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    Plume dispersion of cooling towers is the most important environment problem in environmental impact assessment of an inland nuclear power plant, which greatly impacts the living environment of the residents around the plant. The SACTI (seasonal/annual cooling tower impact) model is used to simulate the plume characters of natural draft of the cooling tower under different environmental temperature and wind speed scenarios in order to determine the influences of the meteorological factors in different seasons on plume dispersion of the cooling tower. The study shows that under different temperature circumstances, the plume length frequency predicted by the SACTI model decreases with the temperature increase. The plume height frequency displays an ascending trend with the descending temperature and shows the descending trend with the ascending temperature. The plume radius frequency has a decreasing change with temperature change. Under different wind speed scenarios, the plume length frequency increases with the increasing wind speed. The plume height frequency displays a descending change with the ascending wind speed. The plume radius frequency with respect to wind speed has a similar varying trend to that of the plume height frequency. The effects of temperature and wind speed on the cooling tower plume are very remarkable and impact cooling tower plume dispersion in different seasons.
  • JIANG Ziying, LIU Weifu
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    The impact pathway approach is applied to establish an accounting framework of externalities of Fukushima nuclear accident and the short-term and mid-term impacts are evaluated, including the public evacuation and relocation, the crops, the seafood, the food and fisheries impacts, the tourism impact, the nuclear power industry losses, the asylum seeker psychological impacts, the clean-up and the restoration of the contaminated areas, and the nuclear accident compensation. The external cost of Fukushima nuclear accident is about 8.6 JPY/kW · h. With respect to the nuclear accident consequence, it is shown that the radiological impacts are small, however, the broad social influence and the economic losses are great, though still smaller than the losses caused by the severe earthquake and tsunami. The main causes of the high external cost of Fukushima nuclear accident are the social activities in the accident emergency and the crisis response measures.
  • WANG Hongzhi, LIU Zhen, LI Donghui
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    Support vector machines (SVMs) have been used for network traffic prediction, but there often exist large prediction errors. This paper presents a network traffic prediction method based on multi-class support vector machine. Through establishing an encoding method in the training phase, the training output is binary encoded, and is established by one to one correspondence with the training input, training the multi-class support vector machine. By constructing a decoding method in the prediction phase, the prediction output is binary decoded, approaching the real value, realizing network traffic prediction and reducing the prediction errors. In simulation experiments, comparison of the real network traffic data and prediction results shows that they have the same evolution trends. Under the same condition, the accuracy of single SVM algorithm is about two times that of BP algorithm, while the accuracy of the proposed algorithm is about two times that of single SVM algorithm. The experiment results show that the proposed method has higher prediction accuracy in contrast with existing algorithms such as those of single SVM and BP neural network.
  • TUERXUN Kelibiena, SIMAYI Mihereguli, WUFUE Dilinuer, AIZEZI Renaguli, UPUR Halmurat
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    This paper discusses the changes of CD41, CD62P, ET-1, t-PA, PAI-1, FIB, APTT, PT, and TT in asthma patients with abnormal Savda. Totally 76 asthmatic patients were syndrome typed according to the body fluid theory of Uygur medicine. Among them, there were 30 asthmatic patients with abnormal Savda and 46 asthmatic patients without abnormal Savda. A comparison study was performed with 89 normal individuals (as the healthy control group). The expression of CD62P on platelets, the level of plasma tissue plasminogen activator (t-PA) and its inhibiter (PAI-1), the level of endothelin-1 (ET-1), activated partial thromboplastin time (APTT), fibrinogen (FIB), prothrombin time (PT) and thrombin time (TT) were tested by using flow cytometer, ELASA method, radioimmunoassay method and auto coagulometer. Finally, we found the followings. Compared to the normal control group, there was no significance between the expressions of the asthma with abnormal Savda group and the asthma without abnormal Savda group (P> 0.05); For the expression of CD62P in all the three groups (P<0.05), the expression of CD62P in the asthma with abnormal Savda group was significantly higher than that of the asthma without abnormal Savda group (P<0.05); The level of serum ET-1 was significantly higher in both the asthma with abnormal Savda and the asthma without abnormal Savda groups (P<0.05); The level of ET-1 was significantly higher in the asthma with abnormal Savda group than those of the asthma without abnormal Savda group and the normal control group (P<0.01); The level of plasma t-PA was significantly lower in both the asthma with abnormal Savda and the asthma without abnormal Savda groups (P<0.05); The level of serum PAI-1 was significantly higher in both the asthma with abnormal Savda and the asthma without abnormal Savda groups (P<0.05); The level of plasma FIB was significantly higher in the asthma with abnormal Savda and asthma without abnormal Savda groups (P<0.05), the level of plasma FIB was significantly higher in the asthma with abnormal Savda group than those of the asthma without abnormal Savda group and the normal control group; The level of APTT and PT were significantly shortened in the asthma with abnormal Savda and asthma without abnormal Savda groups (P<0.05). There was no significance on TT between these three groups.
  • Reviews
  • ZHAO Xiuliang, JIN Xiaofeng, CHENG Xiaolong, ZHOU Jianliang, LEI Long, CAO Zhou
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    This paper introduces the concept of blood born concentration measurement in the process of boron neutron capture therapy (BNCT). The deficiency of the physical, chemical, and nuclear methods for blood boron measurement is analyzed with a focus on the nuclear method. Rapidly and accurately measuring the blood boron concentration is the key in the process of BNCT. The status quo and development of the prompt gamma neutron activation analysis (PGNAA) are discussed. The problems and solutions of existing nuclear measurement methods are summarized. Future techniques for measuring blood boron concentration may be oriented toward fourdimensional estimation of exposure dose in the process of tumor therapy using BNCT.
  • MA Li, LI Bei, DENG Jun, LI Zhenbao, ZHANG Ying
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    The spontaneous combustion of coal storage pile and waste dump is one of the unresolved problems encountered in coal mining and transportation. Thermal probe has a powerful heat transfer capability in a cooling system without external energy. In order to prevent spontaneous combustion of coal storage piles (hillock) due to regeneration, a method using thermal probe to remove heat in coal storage pile is proposed, which damages the regeneration environment to prevent coal fire. In this paper, the characteristics of spontaneous combustion of coal pile are analyzed in detail, and the latest applications and research practices of heat pipe in other industries are also included. Compared with other traditional technologies on coal fire prevention, several advantages of heat pipe in coal fire controlling are described. Technical problems of specific thermal probe, design methods, basic parameters, performance, equipment and implementation technology are discussed. And several measurements are given for its application and promotion, which may enrich the technical means of prevention and control in coal spontaneous combustion.
  • Focus
  • QIAN Sijin
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    From the observation and discussion during the participation in the "Future Circular Collider Study Kickoff Meeting" held in February, 2014 at University of Geneva, this article has introduced the new development in the world high energy physics community which is discussing to design and build a future circular high energy accelerator and collider at CERN through the wide international collaboration; it has briefly retrospected the experiences and lessons of building the high energy accelerators and colliders in the past decades, it has also extracted some view points and suggestions given by the meeting participants. Hope that the long-term development of Chinese high energy physics research can use it for references.