28 May 2013, Volume 31 Issue 15

    

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Articles
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  Preparation and Characterization of Nanofiber Films and Foams Based on Ultrasonic Nanofibrillated Cellulose from Wood

  LU Yun;SUN Qingfeng;LI Jian;

  . 2013, 31(15): 17-22. https://doi.org/10.3981/j.issn.1000-7857.2013.15.001

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  To obtain the nanofibriled-cellulose(NFC) with uniform diameter and high aspect ratio, a chemical pretreatment is employed to remove the hemicellulose and the lignin of Larix gmelini with a subsequent ultrasonic treatment. The chemical characteristics, the crystalline type, the crystallinity and the morphological features of the as-prepared NFC are analyzed by the Fourier Transform Infrared Spectroscopy (FTIR), the X-Ray Diffraction (XRD) and the Scanning Electron Microscopy(SEM). It is shown that the obtained NFC has a uniform diameter of about 35nm and a high aspect ratio(>280). The crystalline type of the NFC is the cellulose I type, and the crystallinity reaches 62.8%, increased by 14.2% as compared with the raw material wood. Simultaneously, the high transparent NFC film and the ultralight flexible NFC foam are also fabricated by using the freeze drying technique.
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  Visualization of Magnetic Resonance Spectroscopy Multi-voxel Based on VTK

  WAN Suiren;DAI Liwen;SUN Yu

  . 2013, 31(15): 23-26. https://doi.org/10.3981/j.issn.1000-7857.2013.15.002

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  Conventional medical imaging is able to see the nidus area visually; however it is difficult to determine the specific type of tumor and the degree of deterioration. The biopsy is a means of trauma check and undoubtedly will bring patients with much pain. Magnetic Resonance Spectroscopy (MRS) uses magnetic resonance phenomenon and chemical shift to study the existence of compounds or the structure of molecules. Nowadays, MRS is becoming a novel check in medical imaging after years of development. MRS is able to reflect the metabolite distribution of brain tissues without invasion, and is of much importance to diagnose and rank brain tumor. During the MRS check for patients, the location selection of MRS voxel is the key for reflecting the metabolite of the lesion correctly. The spatial information of Philips MRS multi-voxel is correctly understood. Based on the development of Visualization ToolKit (VTK), the registration of MRS multi-voxel and MR image is realized and the convenience for doctors to understand the location of the voxel precisely and know the pattern of the tumor better is provided, and the reference for diagnose and further study is offered. It dramatically reduces the dull work for doctors in practice.
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  Dynamic Photoelasticity Method Combined with Laser & Digital Ultra High-speed Camera and Its Applications in Blasting Mechanics

  YANG Liyun;XU Peng;GUO Dongming;YANG Renshu

  . 2013, 31(15): 27-30. https://doi.org/10.3981/j.issn.1000-7857.2013.15.003

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  Combined with pump laser and high-speed digital camera, a new dynamic photoelasticity method is developed, in which the traditional Cranz-Scharding camera is replaced by a new photography system. The new dynamic photoelasticity method was applied in the blasting mechanics, and some digital images, which were much clearer are got. Compared with the traditional dynamic photoelasticity system, the new digital laser dynamic photoelasticity experimental system possesses longer recording time, higher sampling frequency; the results are much more reliable and easy to be processed automatically. It is shown that the new dynamic photoelasticity is useful in the field of blasting mechanics.
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  Security Risk Evaluation for Super Long Tunnel Construction Based on Uncertainty Measurement Theory

  LIU Dunwen;PENG Huaide

  . 2013, 31(15): 31-34. https://doi.org/10.3981/j.issn.1000-7857.2013.15.004

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  For various uncertainty problems in the super long tunnel construction risk evaluation, a new risk evaluation method based on the uncertainty measurement theory is proposed. Fifteen uncertainty measurement function evaluation indexes (e.g. the supporting measures) are chosen according to the characteristics and the causes of the safety accidents in the super long tunnel, and an uncertainty measurement evaluation model based on the uncertainty measurement theory is proposed for predicting the construction risk of the super long tunnel. The weight of each index is calculated by using the information entropy, and the risk grade is predicted in accordance with the confidence identify rules. A new super long railway tunnel is taken as an example, the comprehensive risk rating of the super long tunnel is predicated successfully and its risk level is shown to be the gradeⅡ. The risk evaluation for the super long tunnel construction not only includes the risk grade of the super long tunnel construction period but also reflects the dangerous sources during the super long tunnel construction.
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  Temporospatial Evolution Rules of Acoustic Emission Caused bu the Failure Process of Gas-saturated Coal

  LIU Xingguang;GAO Feng;ZHANG Zhizheng;XING Yan;LI Xiru

  . 2013, 31(15): 35-38. https://doi.org/10.3981/j.issn.1000-7857.2013.15.005

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  To study the temporospatial evolution rules of Acoustic Emission (AE) caused by the failure process of gas-saturated coal, a series of triaxial compression AE tests were carried out by using MTS815 rock mechanics test system and gas seepage test system on raw coal samples with the different gas pressures. The experimental results indicate that the cumulative number of AE locating points gradually increases with load increasing, and the AE locating points mainly distribute in the vicinal area of main crack surface. With load increasing, the AE counts in unit load interval experience initial quiet period, low-level stabilization period in the medium-term, rapid development period before the peak, and high-level stabilization period in the post peak; it is similar to the variation of the cumulative AE counts of coal samples. The increase of gas pressure enhances the AE activity of coal samples before the initial damage, reduces the initial damage stress, and promotes the damage development of coal samples.
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  Optimal Parameter Selection of Geothermal Flash-binary Power System

  LUO Chao;XU Qionghui;YAO Yuan;GONG Yulie;MA Weibin

  . 2013, 31(15): 39-43. https://doi.org/10.3981/j.issn.1000-7857.2013.15.006

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  The flash-binary system includes the single flash power system and the binary cycle system. The flash-binary power system enhances the production as compared with the single flash power system. In addition, compared with the two-stage flash power system, the single flash-binary power system can avoid some problems, such as the bulky equipments, the difficult installment and the high cost. Based on the numerical simulation, the effect of the geothermal water temperature on the net power output, the thermal efficiency and the optimal temperature of the flash-binary power system are discussed in this paper. The simulation results show that, when the temperature is 80℃, the net power output per geofluid is about 1.08 and 0.86 kW·h/t by the direct cooling and the indirect cooling of the flash system, respectively; when the temperature is 150℃, the values are 6.57 and 6.35 kW·h/t; when the geothermal water temperatures are 100, 130 and 150℃, the optimal temperatures of the combined system are 80 and 85℃, 100 and 115℃, 125 and 140℃ by the direct cooling and the indirect cooling of the flash system, respectively. In addition, the power output of the flash-binary system by the direct cooling is dominated by the flash power generation, while that by the indirect cooling is dominated by the binary power generation. The flash-binary power system could provide a technical support for the geothermal resource utilization in China.
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  Visualization Model of the Stratum Three-dimensional Structure Based on GMS and the Prediction of the Neural Network

  WEN Jiwei;;CHEN Chen;;CHEN Baoyi;XU Keli

  . 2013, 31(15): 44-51. https://doi.org/10.3981/j.issn.1000-7857.2013.15.007

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  Through the collection of various typed drilling data in the City of Changchun and the surrounding areas, the visualization model of three-dimensional stratum structure in Changchun and the surrounding areas is established by using the software of GMS. The model fits with the actual geology (topography) quite well, clear reflecting the stratum structure of Changchun, by means of the software, the profile situation of any stratum locations could be also observed. The neural network is introduced, by using hole coordinates (x, y, z), the depth of the stratum, and the thickness of the stratum as input, the corresponding geological age and the lithology (in Chinese and English) is able to be accurately predicted. Using the 5-13-5 structure of the BP neural network (single hidden layer), the average relative error of prediction is 11.12% (among them, minimum error is 7.50%, maximum error is 15.71%); using the improved 5-11-7-5 structure of the BP neural network (two hidden layers), the average relative prediction error is 4.64% (among them, minimum error is 3.63%, maximum error is 6.59%), the requirement for forecast accuracy is fully met.
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  The Reservoir Patterns of Yidong Fault Zone in Yidong Oilfield

  Lü Youliang;LIU Yali;TANG Dazhen;TAO Shu

  . 2013, 31(15): 52-55. https://doi.org/10.3981/j.issn.1000-7857.2013.15.008

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  Under the control of Yidong fault zone, many kinds of oil reservoirs are formed in the north of Sikou sag. Meanwhile, because of the significant tectonic differences exist between the north and the south structures of Yidong fault zone, the reservoir-forming patterns are quite different. Therefore, studying reservoir-forming conditions and patterns has the important significance for further hydrocarbon exploration. Based on the data of core, well logging, well drilling, and seismic analyses, the reservoir-forming conditions and patterns of Yidong fault zone are discussed. The results show that due to abundant source rocks, good reservoir-cap assemblage, and sealing property, the reservoir-forming conditions are quite superior, and many lithologic reservoirs and structural lithologic reservoirs are formed, that have the pattern feature of "turbidite fan" and distribute along the faulted zone. The feature of the fourth member of Shahejie Formation (Es₄) are that the reef limestone lithologic reservoirs are developed upon the south fault terrace, and clastic structural lithologic reservoirs are formed in the north part. In the third member of Shahejie Formation (Es₃), some small nearshore subaqueous fan, turbidite fan structural lithologic reservoirs, and turbidite channel lithologic reservoirs are developed. Nevertheless, fan delta and sandy beach bar structural lithologic reservoirs are mainly developed in the second member of Shahejie Formation (Es₂).
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  A New Method for Predicting the CO₂ Flooding Minimum Miscibility Pressure

  ZHAO Jinsheng;LIU Xiaochun;YANG Tangying;ZHANG Tao

  . 2013, 31(15): 56-58. https://doi.org/10.3981/j.issn.1000-7857.2013.15.009

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  In order to reduce the test time of MMP, according to the principle of interfracial tension disappearing, a new experimental method which is able to quickly determine the MMP is developed. In the experimental method, the main equipment is a rotatable high pressure piston-typed sample preparation container. In order to determine the MMP, the pressure when the oil is mixed with CO₂ is measured. Using the test method of two-phase contact process, the CO₂ MMP of reservoir oil in Chang six of Huaqing has been measured. Comparing with the test result of slim tube test, the MMP result based on two-phase contact process is very closed to the result based on slim tube test. The test method of two-phase contact process possesses features of both simple operation and short test time period.
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  Stress Arching in the Development of the Oil and Gas Reservoirs

  WANG Fanliao;LI Xiangfang;QIAN Qihao;HE Xiangnan;ZHAO Jingjing;ZHANG Xin

  . 2013, 31(15): 59-64. https://doi.org/10.3981/j.issn.1000-7857.2013.15.010

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  Similar to the situation in the mining engineering, there will be a non-uniform deformation in the reservoir and the overburden during the development of oil and gas from underground. A stress arching will occur in the overburden due to this deformation. This deformation is analyzed in this paper and the features of the stress arching are illustrated with field examples. The stress arching ratio is used to describe the degree of the stress arching. The stress arching effect cannot be neglected during the production, otherwise the stress sensitivity will be exaggerated and unreasonable measures will be taken during the development of the low permeability and tight gas reservoirs. For these reservoirs, a part of the weight of the overburden is transferred to the non-formation (i.e sideburden) though the stress arching, which can protect the formation from deforming and eliminate the influence of the stress sensitivity. The range of the arching will increase with the increase of the pressure conductive ability and it will enhance the nature fracture conductive ability inside and outside the arching to improve the productivity and the recovery factor. Therefore, it is possible to use a large pressure drop to develop the low permeability and tight gas reservoir with a large stress arching ratio.
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  Maximum Bearing Capacity Parameters of Stone Arch Bridge Reinforced by Composite Main Arch

  QIAO Wenjing;SONG Yifan;CHEN Shusheng

  . 2013, 31(15): 65-68. https://doi.org/10.3981/j.issn.1000-7857.2013.15.011

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  In order to study maximum bearing capacity of stone arch bridge reinforced by composite main arch, a circular arch bridge on reinforced equality section is analyzed. Characteristics of secondary loading on reinforcement structure and the mechanical properties of the two different materials of new and old structures are considered. The impact of the key structural parameters (height of reinforcing layer, width of reinforcing layer, longitudinal reinforcement ratio of reinforcing layer, and stirrup ratio of reinforcing layer) on the bearing capacity of reinforced main arch ring is analyzed. The results show that when the height of reinforcing layer is 0.25～0.50 times higher than original arch ring, the increment value of bearing capacity is quite obvious; when width of reinforcing layer is in excess of 67% over width of original arch ring, bearing capacity gradually increases; while longitudinal reinforcement ratio of reinforcing layer exceeds 1.162%, the increment value of bearing capacity is quite small; The effect of increasing stirrup ratio of reinforcing layer on bearing capacity of reinforcement arch bridge is relative low. In addition, the results recommend some structural parameters for the design of stone arch bridges reinforced by composite main arch circle method of this kind.
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  A Multi-source Remote Image Feature Extraction and Matching Technology

  LIU Zhiwen;;LIU Dingsheng;LIU Peng

  . 2013, 31(15): 69-72. https://doi.org/10.3981/j.issn.1000-7857.2013.15.012

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  It is difficult to extract the characteristics of matching points because the image intensity in multi-source images is non-linear with respect to pixels. A multi-source remote sensing image feature point extraction algorithm based on the principal oriented component analysis is proposed. In the proposed algorithm, a principal analysis is first made for the multi-source remote sensing images, Secondly, a scale space is built with the first principal components of the multi-source remote sensing images; and the scale parameter is increased to improve the matching accuracy as well as the operation speed of the matching of feature points. This algorithm can extract a certain number of the correct matching point pairs. Comparative analysis of experiments shows that the proposed algorithm enjoys higher precision and better stability than the general algorithms.
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  Properties and Applications of Hollow Glass Microspheres

  DU Juan;HUA Lei;DUAN Huiping

  . 2013, 31(15): 73-79. https://doi.org/10.3981/j.issn.1000-7857.2013.15.013

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  As a kind of special internal hollow spherical materials, the Hollow Glass Microspheres (HGM) have unique and excellent physical and chemical properties as compared with the traditional materials. In recent years, the HGMs have attracted widespread attentions. In this paper, the physical and chemical properties of hollow glass microspheres are discussed, and on this basis the applications of hollow glass microspheres as fillers in resin matrix composite materials, hydrogen storage materials, battery materials, drug carriers, insulation materials, reflective materials, buoyant materials, explosives and cement products are overviewed. With special physical and chemical properties, such as low-density, high mobility and high strength, the hollow glass microspheres can improve the performance of the resin from various perspectives, which greatly extends the design and application fields of the resin-based composite materials; the hollow internal structure and the designable wall structure of hollow glass microspheres provide a wealth of reaction space, are the foundation for the applications in new energy materials and drug carriers; in addition, based on the excellent thermal performance, the high temperature resistant and anti-aging properties, the low-density, the high refractive index and the sensitized performance, the hollow glass microspheres are also widely used in the insulation materials, the reflective materials, the buoyant materials, the explosives, the cement products and other fields. Finally, the future development and the potential applications of hollow glass microspheres are commented.