| 1. |
- Hu, W, et al.
(författare)
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VDM++ Formalization of UML Class Diagram
- 2012
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Ingår i: Weidianzixue yu jisuanji [Microelectronics & Computer]. - 1000-7180. ; 29:6, s. 104-107
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this paper is to use the most widely used formal language-VDM ＋ ＋ that has characteristics of accuracy and consistent in describing syntax and semantic of the system model, combined with VDMTOOLS and Rational Rose tool to transform the various elements of the UML class model into representation of VI）M＋ ＋. This method achieves the various elements contained UML class model about the syntax and semantics checking, and further improves the quality of UML modeling.
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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
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| 6. |
- Hu, W, et al.
(författare)
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Iterative Strategy Analyze During Agile Development
- 2012
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Ingår i: Weidianzixue yu jisuanji [Microelectronics & Computer]. - 1000-7180. ; 29:5, s. 165-169
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, We used characteristic of the Unified Modeling Language （UML） use case model in describing the function of the system＇ s and the iteration sequence of agile development process to obtain a new iteration sequence based on the risk an value of the various use cases in UML use case diagrams. An obvious advantage of doing so is to ensure high-risk and high-value use cases will be first developed, so that the use cases will be repeatedly tested in the next iteration, thereby increasing overall system reliability.
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| 7. |
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| 8. |
- Yang, J, et al.
(författare)
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Web Software Reliability Analysis Based on NHPP Model
- 2012
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Ingår i: Jisuanji Gongcheng [Computer Engineering]. - 1000-3428. ; 38:14, s. 26-28
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This paper proposes a Web Software Reliability Growth Model(SRGM) with BurrX Testing Effort Function(TEF) based on Non-homogeneous Poisson Process(NHPP) and develops its application to Web software reliability analysis. The incorporated TEF depicts the relationship between Web workload and calendar time, and solves the problem about high uneven of Web workload. By using the workload data and failure data from Web logs. Experimental results show that the proposed model can be used to describe the actual failure process more faithfully than G-O model, which is often used to analyze Web software.
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