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101.
102.
Phase formation and modification of corrosion property of nitrogen implanted Ti-Al-V alloy 总被引:1,自引:0,他引:1
In the present investigation, polished samples were implanted with nitrogen ion at an energy of 60 keV and implantation doses were 1×1016, 5×1016, 1×1017 and 6×1017 ions/cm2. Glancing incidence X-ray diffraction was employed on the implanted specimens to understand the phases formed with increasing dose. The valence states of nitrogen, titanium and carbon on the sample surfaces were analyzed by X-ray photoemission spectroscopy. The corrosion resistance was examined by the electrochemical methods in a solution with pH=10 at room temperature in order to determine the optimum dose that can give good corrosion resistance in a simulated nuclear reactor condition. Scanning electron microscopy was used to observe the topographies of nitrogen-implanted Ti-Al-Zr after potentiodynamic measurement. It was found that implanted nitrogen dissolved in titanium matrix with increasing dose and the resultant nitrides such as TiN and Ti2N precipitated. Implantation of nitrogen ions into the surface of Ti-Al-V alloy improves its corrosion resistance, and the increase of the corrosion resistance depends on the nitrogen dose employed; the maximum improvement of the corrosion resistance was observed at a dose of 1×1017 N+/cm2. 相似文献
103.
《Electric Power Systems Research》2006,76(8):663-670
Arcing faults are the most common faults that occur in the 220 kV transmission line national grid of Egypt, in the vicinity of ‘Alexandria’ city. This part of the network also feeds a large industrial load in the form of steel works, which injects a large amount of harmonics into the network. In this paper, the performance of this 220 kV TL network during arcing faults is studied with the aid of the PSCAD/EMTDC program together with a specially designed arcing fault custom model incorporated in the program. Several arcing faults are simulated, and the effect of harmonics on the fault current and secondary arc duration time is demonstrated. Based upon the simulation results, recommendations regarding single-pole autoreclosing and arc suppression methods are suggested. 相似文献
104.
启明星1号装置是我国研究ADS次临界中子学的一个快热耦合系统。本文用离散坐标法的程序TWODANT对启明星1号装置能谱进行分析计算。计算结果表明,启明星1号装置具有比较硬的中子能谱,可用以进行有关ADS的研究。 相似文献
105.
106.
Several V-W-Ti alloys with about 50% reduction in thickness by cold rolling were isochronally annealed at temperatures from 100 to 1100 °C. Hardness was measured after the annealing. By comparison with V4Cr4Ti and V4Ti alloys, the V6WTi alloy was found to begin recovery at a temperature about 100 °C higher, while the full recrystallization temperature was around 900 °C for all of the alloys. Hardness decreased successively above 500 °C in V8W, as is the case in pure V. Impurity induced hardening was observed around 300 °C only in the alloys without Ti. Precipitation and the interaction between interstitial impurities and dislocations were supposed to be the main contributors to the different recovery and recrystallization behaviors of the alloys. 相似文献
107.
HL-2A Tokamak Edge Modeling with B2 总被引:2,自引:0,他引:2
The outer divertor plasma of HL-2A and its associated scrape-off plasma have been simulated using a two-dimensional multi-species fluid code of Braams with a simplified neutral gas model. HL-2A has a double-null closed divertor in separate divertor chambers above and below the nearly circular plasma tours. The computed numerical grid is developed according to an ideal magnetic surface. The calculation is involved only with pure hydrogen plasma. The emphasis has been focused on parametric studies involving variation of the assumptions made for the core plasma. The peak temperatures and the heat flux near the target are of the principal concern。 相似文献
108.
Zhiping Sun Rulin Zuo Cong Li Baoluo Shen Jing Yan Sijiu Huang 《Materials Characterization》2004,53(5):403-409
High chromium white irons solidify with a substantially austenitic matrix supersaturated with chromium and carbon. The subcritical heat treatment can destabilize the austenite by precipitating chromium-rich secondary carbides and other special carbides. In the as-cast condition the eutectic carbides are (Fe,Cr)7C3 and (Fe4.3Cr2.5Mo0.1)C3. The initial secondary carbide precipitated is (Fe,Cr)23C6 after heat-treating at 853 K for 10 h. There are MoC, Fe2MoC and -carbide precipitating, and (Fe,Cr)23C6 transforms to M3C after 16 h at 853 K. The -carbide and (Fe,Cr)23C6 accomplish transformation to M3C and the matrix changes from martensitic to pearlitic after 22 h at 853 K. Thereby, in the subcritical heat treatment process, the initial secondary carbide precipitated is (Fe,Cr)23C6, followed by -carbide, MoC and Fe2MoC. In addition, there are two in situ transformations from (Fe,Cr)23C6 and -carbide to M3C carbides. 相似文献
109.
Xiao Zejun Song Xianhui Lang Xuemei Bai Xuesong Ma Jieliang Wang Pengfei Chen Bingde 《Nuclear Engineering and Design》2004,229(2-3):213-222
One of the most important requirements in the design of pressurized water reactor (PWR) is to avoid the occurrence of critical heat flux (CHF). The design criteria for PWR specify that they must be operated at a certain percentage below CHF at all times and locations so as to the cladding temperature of fuel element at safe values. So in the process of safety assessment, CHF is one of important thermal-hydraulic parameters limiting the available power, whose size directly affects safety and economy of PWR nuclear power plant. This paper deals with a summary of experimental research progress on CHF of Chinese PWR. It mainly presents CHF experimental researches of Φ10 fuel assembly, CHF experimental researches of standard fuel assembly, and CHF experimental progress of non-uniform heated rod bundles. It should be emphasized that it also presents experimental research programs on CHF of Chinese advanced fuel assembly with self-reliance copyright. All CHF data obtained will be used for design improvement of Chinese PWR and R&D program of New Generation 1000 MWe PWR. 相似文献
110.
介绍了以Ta/Ta2O5/Cu为结构的平板MIM电容器的制备方法和性能测试,探究金属Cu直接作为钽电解电容器阴极层的可行性。通过阳极氧化法在钽箔表面制备非晶态的Ta2O5薄膜,以化学镀铜、磁控溅射镀铜两种镀铜工艺制备Ta/Ta2O5/Cu结构,并对所得结构进行结构表征和性能测试。实验结果表明:不同镀铜方式制备的Ta/Ta2O5/Cu结构在电学性能测试过程中都没有表现出电容特性,正负极之间的电阻仅有0.7Ω;以金属Cu直接作为钽电容器的阴极层会导致金属铜在测试过程中被氧化成铜离子从而进入Ta2O5介质层中,进而导致Ta2O5的击穿,因此金属铜不适合直接作为钽电容的阴极层。 相似文献