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| 2. |
- Chen, Xiangrong, 1982, et al.
(författare)
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Study on conducting characteristics of electrical trees in cross-linked polyethylene cable insulation
- 2012
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Ingår i: Wuli Xuebao/Acta Physica Sinica. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 61:8, s. Art. no. 087701-
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Tidskriftsartikel (refereegranskat)abstract
- The conducting characteristics of two typical electrical trees in cross-linked polyethylene (XLPE) cable insulation are studied by a combination of optical microscopy observation, partial discharge measurement and con-focal Raman spectroscopy analysis. Although they are grown under similar conditions, these two trees display very different shapes. One is a typical branch-pine tree grown at 9 kV, and the other is a branch tree grown at 11 kV. The growth and the partial discharge regularities show obvious differences. The disordered graphitic carbon is condensed in the main tree channels of the branch-pine tree. From the relative intensity of the graphitic carbon G band to D band, the graphitic domain is estimated to be about 8 nm in size. The tree channel resistance per unit length is less than 10 Ω· μm-1, which is sufficient to prevent the partial discharge from developing within the tree structure. The branch-pine tree shows the features of the conducting tree. The fluorescence background is observed in the channels of branch tree, which shows the existence of the products of the material degradation, but no disordered graphitic carbon is observed in these tree channels. These tree channels display obvious non-conducting characteristics, which is not sufficient to prevent the continuous effect of the partial discharges. Finally, a single channel growth model is proposed for the conducting and non-conducting trees grown in XLPE cable insulation. Based on the equivalent circuit theory, the growth mechanisms of the two trees with different conducting characteristics in XLPE cable insulation are discussed.
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| 4. |
- Deng, Qihong, et al.
(författare)
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Source Apportionment and Chemical composition of particulate matter (PM10) in university classrooms
- 2009
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Ingår i: Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology). - 1672-7207. ; 40:2, s. 332-328
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Tidskriftsartikel (refereegranskat)abstract
- The inhalable particulate matter (PM10) was continuously monitored and sampled in the classrooms of Central South University at Changsha by Tapered Element Oscillating Microbalance 1400a (TEOM 1400a) from September to December, 2007. The chemical compositions of the PM10 samples were analyzed by the X-ray fluorescence (XRF), and then the source apportionment of the classroom particles was investigated by the principal component analysis (PCA). The results show that the mean PM10 concentration in classrooms is (176.56±57.63)
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- Dodig Crnkovic, Gordana, 1955
(författare)
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高丹娜·多迪格—克恩科维奇.智能社会的计算信息:决策的信息—计算进路[J].王健,译.重庆邮电大学学报(社会科学 版) - Computing Information for Intelligent Society: Info-Computational Approach to Decision Making
- 2022
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Ingår i: Journal of Chongqing University (Social Science). The Proceeding of Xi'an Senior Forum. ; 34, s. 62-67
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Tidskriftsartikel (refereegranskat)abstract
- With the powerful development of pervasive information-based technology, especially intelligent computing, the question arises: How do we imagine a future highly developed and humane (human-centered) intelligent information society? The answer will of course vary depending on time perspective. In a shorter-time perspective, we can try to anticipate based on the existing trends in the development. The first step is to understand the current state of the art of intelligent technology uses towards intelligent society. A longer-term perspective is more uncertain, as new intelligent technologies, especially in combination with biotechnologies and human augmentation and enhancement will be changing both the ways of being human as well as the structures and behaviors of human societies, as argued by (Wu & Da, 2020) under the heading “The Impact of Intelligent Society on Human Essence and the New Evolution of Humans”. Wu and Da anticipate that the development of widely used AI technologies will lead to the evolution of the “human essence” that will lead to the convergence between social and biological evolution. That is a radically optimistic view that declares equality between the increase in human freedom with the disappearance of the necessity of regular human labor as a means to assure physical existence. In the future intelligent automated society, machines will secure the material basis of existence for everybody. It will remain to humans how to meaningfully use this newly conquered space of freedom.
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| 6. |
- Fu, L. H., et al.
(författare)
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Influence of Cr3C2 content on the wear properties of Cr3C2/Ni3Al composites
- 2016
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Ingår i: Gongcheng Kexue Xuebao/Chinese Journal of Engineering. - 2095-9389. ; 38:8, s. 1145-1152
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Tidskriftsartikel (refereegranskat)abstract
- The Ni3Al-alloy and its composites with different Cr3C2 contents were fabricated by a hot isostatic pressing (HIP) technique. The influences of Cr3C2 content on the microstructure, hardness and wear properties of the Cr3C2/Ni3Al composites were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and wear tribometry. The results show that inter-diffusion occurs between the original Cr3C2 and the Ni3Al particles during the HIP process and the Cr3C2 particles partially transform into M7C3 (M=Cr, Fe, Ni) structures. Under specific friction and wear conditions, the wear resistance of the Cr3C2/Ni3Al composites is significantly improved due to the addition of Cr3C2 particles by about 4-10 times, compared to the Ni3Al alloy. In addition, the cutting and scraping effects of counter-part disks by the Cr3C2/Ni3Al composites decreases with increasing Cr3C2 addition, resulting in a reduction in wear rate of counter-part disks.
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| 7. |
- Fu, L. H., et al.
(författare)
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Microstructure and phases constitution of Cr3C2/Ni3Al composites prepared by hot isostatic pressing (HIP)
- 2016
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Ingår i: Journal of Iron and Steel Research. - 1001-0963. ; 28:12, s. 52-58
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Tidskriftsartikel (refereegranskat)abstract
- The Cr3Cj/Ni3Al composite materials were prepared by hot isostatic pressing (HIP) at 1160°C and 100MPa. Microstructure and phases constitution of the composite materials were investigated. The results indicate that the original Cr3C2 particle firstly dissolves into Cr and C atoms and then diffuses into the matrix. During the cooling process, the dissolved Cr and C atoms transformed into a stable Cr7C3 structure. Also, an uphill diffusion phenomenon is observed for Fe element from the matrix to the Cr7C3 carbide phase, which is attributed to the easy formation of stable carbides of Fe element in Ni3Al alloy with C element. And, the Fe atoms substitute a part of Cr atoms in Cr7C3 carbides and form a diffusion phase with M7 C3 (M for Cr, Fe) structure. When the original Cr3Q2 particles are large, it cannot be completely dissolved during the high temperature period. The undissolved core of Cr3C2 particles still remain the Cr3C2 structure after the cooling process. The Cr3C2/Ni3 Al composite materials are composed of Cr3C2 hard core phase, M7C3 diffusion phase and ?-Ni3Al matrix material phase. The Cr3C2 hard core phase and the ?'-Ni3Al matrix created a good diffusion bonding by the formed M7C3 diffusion phase. Therefore, the Cr3C2 particle on the worn surface does not peel off and the groove is interrupted around the chromium carbides during the wear test, resulting in significantly improved wear resistance of Cr3C2/Ni3Al composites.
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| 8. |
- Fu, L., et al.
(författare)
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Wear mechanism of Cr 3 C 2 /Ni 3 Al composites showing excellent wear resistance
- 2019
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Ingår i: Gongcheng Kexue Xuebao/Chinese Journal of Engineering. - 2095-9389. ; 41:1, s. 117-123
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Tidskriftsartikel (refereegranskat)abstract
- The Ni 3 Al intermetallic compound is considered an excellent wear-resistant material. The addition of Cr 3 C 2 particles can further improve the wear resistance of Ni 3 Al-based alloys. In order to elucidate the wear mechanism of Cr 3 C 2 /Ni 3 Al composites improved by the Cr 3 C 2 strengthening phase, Ni 3 Al-alloy and Cr 3 C 2 /Ni 3 Al composites were prepared by the hot isostatic pressing process in this study. The mechanical properties and wear resistance of each phase in the Ni 3 Al-alloy and Cr 3 C 2 /Ni 3 Al composites were investigated using a nano-indentation instrument and a pin-on-disk friction and wear tester, respectively. The worn surface morphologies and the hardness of the subsurface layer under the worn surfaces of the Ni 3 Al-alloy and Cr 3 C 2 /Ni 3 Al composites were determined by a scanning electron microscopy (SEM) and a nano-indentation instrument. The results indicate that the hardness of the matrix phase in the Cr 3 C 2 /Ni 3 Al composites is significantly improved by the addition of Cr 3 C 2 particles. The nano-hardness and the elastic modulus of each phase in the Cr 3 C 2 /Ni 3 Al composites gradually increase from matrix phase through diffusion phase to hard core phase. The mechanical properties between the matrix, diffusion, and hard core phases in the Cr 3 C 2 /Ni 3 Al composites present a gradient transition. This kind of structure distribution is good for enhancing the wear resistance of Cr 3 C 2 /Ni 3 Al composite materials. As for friction and wear conditions in this study, abrasive wear was the dominant wear mechanism, which occurred on the surfaces of the Ni 3 Al-alloy and Cr 3 C 2 /Ni 3 Al composites. The Cr 3 C 2 /Ni 3 Al composites showed a good wear resistant property. The carbide-strengthening phase can block up the cutting action of the wear debris, reduce the interaction between the wear materials, and decrease the thickness of the subsurface layer and the size of the wear debris, resulting in improved wear resistance of Cr 3 C 2 /Ni 3 Al composites.
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| 9. |
- Han, Y., et al.
(författare)
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A study on the dynamic responses and injury mechanism of human chest in vehicle-pedestrian collisions
- 2015
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Ingår i: Qiche Gongcheng/Automotive Engineering. - 1000-680X. ; 25:5, s. 516-519, 537
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Tidskriftsartikel (refereegranskat)abstract
- With THUMS pedestrian FE model, simulations on vehicle-pedestrian crash are conducted for four types of vehicles (medium sedan, minicar, van and SUVs) with different front-end structures at a impact speed of 20, 30, 40 and 50km/h to analyze pedestrian chest dynamic response and chest impact conditions as well as the chest deformation modes and injuries of pedestrian including rib deflections. The results demonstrate that the front-end structure of vehicle has significant effects on the dynamic response and chest impact speed of pedestrian and the stiffness distribution of vehicle front-end structure is a major factor affecting the rib deflections and chest deformation mode of pedestrian.
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| 10. |
- Han, Yong, et al.
(författare)
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Finite Element Analysis of Lower Extremity Fractures in Vehicle-Pedestrian Collision
- 2011
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Ingår i: Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (Engineering and Technology Edition). - 1671-5497. ; 41:1, s. 6-11，id.1671-5479(2011)01-0006-06-
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Tidskriftsartikel (refereegranskat)abstract
- A finite element Human Body Model (HBM) of lower extremity was improved based on the geometry of human skeleton anatomy. The model consists of the pelvis, the femur, the tibia, the fibula, the patella, the foot bones, primary tendons, knee joint capsule, meniscus, and ligaments. This model is constructed using shell and solid elements also including linear spring-damper elements, it contains of 29777 nodes and 30873 elements. The whole model was validated by comparing the results of simulation with these from shearing-bending cadaver tests described in literature. Then the FE HBM of lower extremity and an existing multi-body system (MBS) human model of the pedestrian were used to reconstruct the real-world vehicle-pedestrian accident and lower limb injuries. Results of injury reconstruction show that this FE model has a good biofidelity and biomechanical response, and can be applied in research on lower limb injury mechanisms and used in the development of injury protective devices.
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