28 August 2014, Volume 32 Issue 24

    

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  Ebola Virus Disease: Epidemiology, Ecology, Diagnosis, Treatment, and Control

  LI Yu, REN Xiang, LIU Di, CHENG Ying, GAO George Fu, YU Hongjie

  journal1. 2014, 32(24): 15-24. https://doi.org/10.3981/j.issn.1000-7857.2014.24.001

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  Ebolavirus is the causative agent of Ebola Virus Disease (EVD) and was first found in 1976 in Africa. The genus of Ebolavirus includes 5 species, of which the 4 species, i.e., Sudan ebolavirus, Zaire ebolavirus, Taï Forest ebolavirus and Bundibugyo ebolavirus caused human cases of EVD in the history. The additional species, Reston ebolavirus, was associated with several outbreaks among monkeys and was once isolated from domestic pigs of Philippines. EVD has a fatality rate between 25% and 90%, with its outbreaks in humans limited to Africa and mainly happened in central Africa between 10°N and 10°S so far. The ongoing outbreak in West Africa has been the biggest one, with 2615 cases reported as of August 20, 2014. EVD is widely considered to be a zoonosis and its most likely natural reservoirs are fruit bats based on the current evidence. Ebolavirus can spread within human, mainly through contact of blood and secretions of patients presenting symptoms and the contaminated objects as well. So the health care staff, home care person and individuals with contact of corpse of EVD cases are the high risk population for infection. EVD has an abrupt onset of early symptoms such as fever, anorexia and weakness, which are nonspecific. But the disease can be diagnosed through testing RNA, antigen, or antibody. There have been no licensed drugs or vaccine in the market, while the treatment is still limited to treating the symptoms as they appear and supportive care. The current strategy for prevention and control includes early detection of cases, rapid investigation and response, tracing and close observation of high risk contact, and effective infection control in the health care facilities and the community.
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  High Temperature Deformation Behavior of a High Strength and High Toughness TC27 Titanium Alloy

  ZHANG Yeqin, GU Zhifei, SHA Aixue, HUANG Lijun, LU Shiqiang

  journal1. 2014, 32(24): 25-30. https://doi.org/10.3981/j.issn.1000-7857.2014.24.002

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  The high temperature deformation behavior of TC27 titanium alloy with high strength and high toughness was studied through isothermal constant strain-rate compression experiments using a Gleeble 3500 thermo-mechanical simulator, which might provide reference for thermal processing of TC27 titanium alloy. The results show that the stress-strain curves of TC27 titanium alloy at low temperature and high temperature roughly corresponded to the softening type and steady-state-flow type, respectively, and significant shock decline was observed when the strain rate was 70 s^-1. The dependence of temperature on flow stress at low temperature was much more significant than that at high temperature, and the dependence of strain rate decreased when the temperature was increased. Based on experimental data, two high precision constitutive equations of TC27 titanium alloy were established for temperature ranges of 700-850℃ and 850-1150℃. Observation on the microstructure shows that the amount of dynamic recrystallized grains increased with the rise of temperature or the decrease of strain rate when the temperature was higher than β transition temperature.
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  Influence of S^2-Concentration on the Corrosion Resistance of 10^# Carbon Steel in Saline Wastewater

  GUO Lin, XU Xiuqing

  journal1. 2014, 32(24): 31-34. https://doi.org/10.3981/j.issn.1000-7857.2014.24.003

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  The corrosion of a refinery heat exchanger, especially a water-phase heat exchanger, is a serious issue. The corrosion perforation and scaling of tubes are the main causes for the heat exchanger failure due to the existence of plenty of S^2-, Cl^-, Ca²⁺ and Mg²⁺ in the corrosion medium. Based on the experience of corrosion of refinery heat exchanger tubes (10^# carbon steel) in their operation processes, the corrosion behaviors of 10^# carbon steel in saline wastewater with different S^2-concentrations are investigated by means of the immersion test and the electrochemical methods. The surface photographs and the compositions of corrosion products are taken and determined by digital camera and X-ray diffraction spectrometer. The experiment results indicate that the uniform corrosion rates of 10^# steel decrease gradually with the increase of the S^2-concentration in the corrosion medium within the scope of the test. The corrosion degree of 10^# carbon steel comes down to a moderate corrosion from a heavy corrosion when the S^2-concentration in the medium is higher than 250 mg/L. XRD results show that the main compositions of the corrosion products are Fe₃O₄, CaCO₃ and FeS. Meanwhile, Cl^- in the corrosion medium can penetrate the corrosion product to accumulate and produce the pit corrosion on the surface of 10^# carbon steel because of the existence of Cl^-when the S^2-concentration in the medium was less than 100 mg/L. And the pitting corrosion resistance becomes worse with the decrease of the S^2-concentration.
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  Effects of Sediments on the Corrosion Behavior of 20^# Carbon Steel Pipe

  GAO Qiuying, ZHANG Jiangjiang, YANG Zuguo, YANG Dongming, LIU Jining, ZANG Hanyu, ZHU Yuanyuan, ZHANG Tao

  journal1. 2014, 32(24): 35-39. https://doi.org/10.3981/j.issn.1000-7857.2014.24.004

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  The main material of the crude oil gathering and transportation pipeline in Tahe oilfield is 20^# steel. The pipeline surface corrosion is mainly the wall pitting corrosion, with deposits in the pitting region. In order to study the corrosion behavior of sediments on the ground crude metal pipeline, based on the analysis on the sediment types on the inner wall of the pipeline, the cover of 20^# carbon steel specimen with or without sediments is hanged in the autoclave to simulate the scene corrosion experiment, using the weight loss method, the polarization curve test, the wire beam electrode test and the scanning electron microscopy. With 20^# carbon steel corrosion sediments under the coverage of the test piece, the weightlessness velocity, the corrosion process, the corrosion potential distribution and the SEM characteristics are determined, with no sediment covering the 20^# carbon steel specimen. It is shown that in the area of 20^# carbon steel without sediment covered, the corrosion weight loss rate is smaller than that with sediments covered; both corrosion processes are governed by the diffusion control, the latter by promoting the anodic process and reducing the corrosion potential and the corrosion resistance; the distribution of the corrosion potential does not change with time, the general corrosion, the corrosion potential distribution varies with time, with prominent pitting characteristics.
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  Formation Mechanism of Aggregated Type Natural Bitumen with High Evolution Degree: With Vein Anthraxolite in Xiangxi as an Instance

  WANG Chongjing, CAO Daiyong, CHEN Jianming, ZHANG He, ZHOU Rongzhou, ZHOU Ji, YANG Guang

  journal1. 2014, 32(24): 40-45. https://doi.org/10.3981/j.issn.1000-7857.2014.24.005

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  The metamorphic grade aggregated type natural vein anthraxolite is widespread in Cambrian strata in Xiangxi, Hunan. The characteristics of its occurrence and microscopic morphology, the source, the composition and the evolution degree are obtained based on the field investigation and analysis. Anthraxolite Veins are hosted mainly in the NE-NNE small faults. With the SEM-EDX (scanning electronic microscopy with energy dispersive X-ray), the XRD techniques and the Fourier transform infrared spectrophotometer (FT-IR), the chemical composition, the morphology and the molecular structure characteristics are identified. The data suggest that the anthraxolite is in a high evolution stage because of the flow structure and the mosaic texture of the SEM images and the graphite diffraction peak of XRD. The functional groups from the Fourier infrared absorption spectrometry illustrate the anthraxolite derived from the kerogen evolution. The anthraxolite with the characteristics of the original oil is shown, and it is influenced in the later stage, which sometimes even covers up the original features.
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  Reservoir Classification and Application Based on Mercury Injection Coefficient

  YANG Ling, CHENG Daojie, LIU Baolei, BAI Songtao

  journal1. 2014, 32(24): 46-50. https://doi.org/10.3981/j.issn.1000-7857.2014.24.006

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  This paper proposes a reservoir classification method based on mercury injection data, according to the principle that the characteristic parameters in mercury injection method reflect the pore structure and permeability of the reservoir. Firstly, the lower limit of porosity was determined and the sensitive characteristic parameters were selected from the mercury injection data. The relationship map of property and oiliness of the study area shows that the lower limit of porosity of Kong 2 Member is 11%, namely the upper limit of the forth type of reservoir. However, the relationship map between electricity and oiliness shows that the lower limit of porosity of Kong 2 Member is 15%, namely the upper limit of the third type of reservoir. Relationship analysis of the mercury injection parameters and RQI shows the average pore throat radius, replacement pressure and sorting coefficient are the sensitive parameters that reflect effectiveness of the reservoir. The mercury injection coefficient that describes reservoir effectiveness was founded, and the classification standard based on mercury injection data was founded. Finally, the reservoirs are classified into four types. The quality of the first type is the best, and that of the fourth type is the worst. The logging data was processed by this method and the effect was checked by the physical property, particle size and oil test data. The results demonstrate that this method is reasonable and reliable.
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  Pipeline Resistance Model of the Filling Slurry Transportation with High Concentration and Superfine Total Tailing

  ZHANG Qinli, JIANG Zhiliang, WANG Shi, CHEN Qiusong, ZHU Yangya, WAN Xiaoheng

  journal1. 2014, 32(24): 51-55. https://doi.org/10.3981/j.issn.1000-7857.2014.24.007

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  In order to accurately calculate the pressure loss in a filling pipeline with superfine total tailing and high concentration slurry in a mine, on the basis of the solid-liquid two-phase flow theory, the factors that affect the backfilling pipeline resistance of the total tailing slurry are analyzed, to obtain a calculation model of the pipeline transportation resistance with a high concentration and superfine total tailing slurry through the dimensional analysis. According to the method of the computational fluid dynamics (CFD), the effects on the filling pipeline resistance of some factors, like the slurry volume concentration, the flow rate, the pipe diameter, the solid mixture density and others, are evaluated, 360 groups of the pipeline resistance loss values are obtained; Using the least squares and linear regression method, the parameters in the transportation resistance model are calculated. With four common operating points selected, an error analysis of the calculation model is made, and according to the method of the regression coefficient significance test, the degree of the influence on the pipeline resistance loss of each factor is obtained finally. The error of the calculation model results against those of the pumping experiment with loop is around 5%, so it could meet the needs of the engineering design and can be used to reduce the pipe resistance.
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  Phase Transition of Network Based on Traffic Routing Model

  SUN Lei, LI Rong, CHEN Xiaoguo

  journal1. 2014, 32(24): 56-59. https://doi.org/10.3981/j.issn.1000-7857.2014.24.008

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  With the development of complex networks, more and more attentions are paid to the phase transition. The phase transition is a process of transition from a stable state to a congested state. In this process, three kinds of variations of loads on the network are involved, which are the total loads on the network, the loads removed from the network and the loads waiting for passing through some node. Firstly, based on the traffic routing model, an order parameter is introduced to characterize the phase transition. With the increase of R (the number of loads which enter into the network per unit time), this parameter experiences a transition from zero to non-zero. That is to say, there will be a critical value of R_c that characterizes the traffic phase transition from a stable state to a congested state. Secondly through the simulation, the variations of different kinds of loads on a scale-free network are identified. The node with the maximum betweenness is easily to be congested, which results in an unbalance between the loads that enter into the network and the loads that are removed from the network, and eventually results in the network congestion; When R<R_c, the number of loads that are removed from the network increases synchronously with R. When R>R_c, the ratio of the number of the loads removed from the network and R decreases gradually, which means that it is more and more difficult for the loads to reach their destination. Understanding the variations of the key indicators in the phase-transition process is beneficial for the effective prevention and intervention against the network.
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  Quantum Diffraction of Wave Function in Time-domain by Bloch Vector Model

  LIU Birui, FU Zhenxing

  journal1. 2014, 32(24): 60-63. https://doi.org/10.3981/j.issn.1000-7857.2014.24.009

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  To explore the physical mechanism and the essence of the quantum diffraction in time-domain, the wave function diffraction in time-domain of a two-level system under the pulse field with a chirped frequency is investigated by means of the density matrix equation and the Bloch vector model. The modulations of the quantum diffraction by the chirped factors are discussed. The dynamic evolution process of the population transfer and the effect of the quantum diffraction with different chirped factors are analyzed. The interaction mechanism and the physical process can found a clear description in the Bloch vector picture.
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  Calibration of a Line Structured Light Vision Measuring System Based on the Drawing Method

  CUI Ximin, LI Cong, YUAN Debao, HONG Xueqian, ZHAO Yi

  journal1. 2014, 32(24): 64-67. https://doi.org/10.3981/j.issn.1000-7857.2014.24.010

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  The line structured light vision measurement technology is widely used as a non-contact measurement technology. This paper proposes a method for structured light vision measurement calibration based on the drawing method by analyzing the mathematical model of the visual measurement sensor and using the feature point constructed on the light plane. This method has simple process and reduces the cost of calibration equipment, laying the foundation for line structured light engineering application. The calibration results show that the method meets the measurement requirements.
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  Intercept Flight Test Method of Civil Aircraft Noise Certification

  YAN Guohua, ZHOU Limin

  journal1. 2014, 32(24): 68-72. https://doi.org/10.3981/j.issn.1000-7857.2014.24.011

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  Civil aircraft noise certification usually requires repeated flight tests, which is costly and time-consuming. This paper proposes a complete intercept flight test method to reduce the costs and shorten the certification period. The intercept flight procedures of take-off and approach noise measurement test were established based on the establishment principle of equivalent aircraft noise certification procedures approved by International Civil Aviation Organization. The method for determining 10 dB-down period is summarized with a specific type of jet as example. The intercept flight test method is of high application value for the noise certification of future ARJ21-700 derivative types and C919.
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  Sedimentation Processes in a Typical Riparian Zone Along the Yangtze Mainstream of the Three Gorges Reservoir

  TANG Qiang, HE Xiubin, BAO Yuhai, ZHONG Ronghua, YAN Dandan, GAO Jinzhang

  journal1. 2014, 32(24): 73-77. https://doi.org/10.3981/j.issn.1000-7857.2014.24.012

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  A typical transect of the riparian zone along the Yangtze mainstream of the middle Three Gorges Reservoir is selected to determine the lateral distribution of sedimentation rates against elevation, and to explore the effect of the reservoir water level regulation and the seasonal variation of suspended sediment concentrations of the Upper Yangtze River. It is found that the net sedimentation mainly takes place within the portions between 145-168 m. The cumulative net sediment depth ranges from 1.1-39.9 cm during the 2010 survey and it decreases with the increase of the elevation. The average sediment depth is 14.9 cm between the elevations of 145-155 m, and 2.6 cm in the portions above. The sediment depth ranges from 3-80cm during the 2013 field survey, indicating the severity of the sediment accretion during the initial period of dam operation. The riparian sediments become coarser with the increase of the elevation, which indicates that the sandy fraction of the bulk sediment increases at a higher elevation. The sediment grain-size composition at lower elevations is close to that of the suspended sediment, while that at a higher elevation is coarser than the suspended sediment. The sedimentation in the riparian zone is closely related to the water level regulation induced by the regular dam operation. During a wet season when the reservoir water level is low, a high fluvial suspended sediment yield leads to a significant sedimentation in the lower portions of the riparian zone. During the dry season when the fluvial suspended sediment supply is limited, much fewer sedimentation occurs at the upper portions. Relatively longer inundation duration also contributes to a higher sediment depth in the lower portions of the riparian zone. It can thus be concluded that the sediment in the lower portions of the riparian zone is due to the fluvial suspended sediment yield during the wet season, while the sediment in the upper portions of the riparian zone originates from the bank erosion.
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  Features of the Ecological Governance Activity of WWF as Seen from Its Yangtze River Program

  SUN Mengxin

  journal1. 2014, 32(24): 78-83. https://doi.org/10.3981/j.issn.1000-7857.2014.24.013

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  As the largest international non-governmental organization engaged in the global ecological conservation, the 1961-born World Wide Fund for Nature (WWF), during its ecological governance practices worldwide over the past decades, has accumulated a great deal of experiences in the ecological conservation and the environmental protection. In applying these experiences to China, WWF has demonstrated high adaptability and flexibility in accommodating China's specific situation, and this could be seen in its adherence to advanced conceptions, and also in its approaches in conducting specific projects. In the past years, WWF has made a remarkable progress in its participation in China's ecological governance, and has gained applauses from the relevant Chinese stakeholders. This paper analyzes two typical cases among the many projects in WWF's Yangtze River conservation program, and summarizes the outstanding features of WWF in conducting ecological governance activities in China. On basis of this, the paper provides some lessons that China could learn from this organization.