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51.
Cancer statistics, 1993 总被引:1,自引:0,他引:1
52.
离子注入对Cr12MoV钢表面组织结构和力学性能的影响 总被引:1,自引:0,他引:1
研究了Cr12MoV钢离子注入层的显微组织特征及其对表面性能的影响。结果表明,离子注入使Cr12MoV钢的表面硬度和耐磨性能得到显著改善,且存在着一个最佳的注入剂量,约为3×10^1^7N^+/cm^2左右。离了注入在Cr12MoV钢表面层中形成了大量细小弥散的第二相粒子,并使α-Fe晶格发生严重畸变,从而引起材料表面强化。 相似文献
53.
The objectives of this paper are to quantify the effect of Marangini convection on the absorption performance for the ammonia–water absorption process, and to visualize Marangoni convection that is induced by adding a heat transfer additive, n-octanol. A real-time single-wavelength holographic interferometer is used for the visualization using a He–Ne gas laser. The interface temperature is always the highest due to the absorption heat release near the interface. It was found that the thermal boundary layer (TBL) increased faster than the diffusion boundary layer (DBL), and the DBL thickness increased by adding the heat transfer additive. At 5 s after absorption started, the DBL thickness for 5 mass% NH3 without and with the heat transfer additive was 3.0 and 4.5 mm, respectively. Marangoni convection was observed near the interface only in the cases with heat transfer additive. The Marangoni convection was very strong just after the absorption started and it weakened as time elapsed. It was concluded that the absorption performance could be improved by increasing the absorption driving potential (xvb−xvi) and by increasing the heat transfer additive concentration. The absorption heat transfer was enhanced as high as 3.0–4.6 times by adding the heat transfer additive that generated Marangoni convection. 相似文献
54.
Public participation is essential in each step of the nuclear-related decision-making process. Recently, the electronic systems using the Internet have become quite popular, and have emerged as a good medium for communicating with the public. In this study, a comprehensive utilization of electronic public participation was used to analyze public opinion on a given nuclear-related decision-making process. The degree of deliberation and meditation of the public participating in an electronic poll survey was evaluated, and the decision-making factors representing the personal characteristics of the poll respondents such as age, income, education, residence, degree of knowledge and concern were carefully incorporated when preparing the poll-survey questionnaire for its evaluation. Fuzzy analysis was used to assess and aggregate the responses to each decision-making factor. As a case study, this procedure was used to analyzing public opinion on the location of a low-level radioactive waste disposal facility on the campus of Seoul National University. The results show that there is a tendency of respondents who are on the negative side of the argument to be more deliberate and meditative in their decision-making process than those on the positive side. Knowledge and residence were found to be important decision-making factors. 相似文献
55.
Factors affecting the activity of anammox bacteria during start up in the continuous culture reactor. 总被引:5,自引:0,他引:5
Factors affecting cultivation of extremely slow-growing bacteria (anaerobic ammonium oxidiser, doubling time 11 days) were investigated by using upflow anaerobic sludge blanket (UASB) reactors which can maintain high solid retention time. The effects of concentrations of DO, free ammonia (FA), and nitrite on activation of anammox activity were tested during the start-up period. The reactor was inoculated with granular sludge collected from a full-scale UASB reactor used for treating brewery wastewater, and sludge from a piggery wastewater treatment plant and rotating biological contactor treating sewage. Results of continuous operation showed that concentrations of DO, free ammonia (FA) and nitrite in the reactors played a key role in stimulating the anammox activity during start-up period. It is crucial to keep DO below 0.2 ppm, FA below 2 mg/L and nitrite nitrogen below 35 mg/L to cultivate anammox cells in the continuous bioreactor. When the levels of DO, FA and nitrite in the influent were controlled at less than the inhibition levels, the anammox activity increased gradually in the anaerobic condition. Addition of hydrogen sulphide into the reactor enhanced anammox activity in the continuous culture. Through the SEM, TEM and FISH analysis, anammox bacteria were detected in the granular sludge after 3 months of continuous operation. 相似文献
56.
Kai Kang 《Fire Technology》2007,43(4):331-346
This paper presents an emergency evacuation analysis during a mid-platform train fire in an underground rail station. A time-based
evacuation scenario is developed taking into account the stairway inaccessibility due to smoke blockage. The calculation approach
in NFPA 130 is then applied to a parametric study of this time-based scenario and its reliability is examined using a micro-simulation
model. Both methods give consistent predictions of the exiting times. The results demonstrate that with the division of the
station into two zones, the exiting time could not meet the code requirements, whereas it does meet the required exiting time
without the division. Such division is due to smoke blockage and creates an uneven ratio of the occupant load to the available
exiting capacity. This shows that appropriate consideration of the fire and smoke effects is important for station egress
evaluation. Other issues such as the fire growth rate and the pre-evacuation time are also discussed. 相似文献
57.
58.
59.
采用传递比较法对二厘米微波衰减标准装置不确定度进行了验证。测量标准装置的重复性以组内实验标准偏差sn(A)定量表征,测量标准装置的稳定性用组间实验标准偏差sm定量表征。 相似文献
60.
K. Lefmann B. Lake G. Aeppli S.-W. Cheong N. B. Christensen K. N. Clausen S. Hayden T. E. Mason D.F. McMorrow H. A. Mook H. M. Rønnow H. Takagi 《Journal of Low Temperature Physics》2004,135(5-6):621-664
One important area of modern condensed matter research is the investigation of the nature of the superconducting cuprates. Much progress in this field has been obtained with the technique of neutron scattering. We here present a review of neutron scattering studies of the high-temperature superconductor La2?xSrxCuO4, performed at Risø National Laboratory. We review the work on the mapping of the incommensurate spin fluctuations, the investigation of the gap in the fluctuation spectrum, the magnetic properties of the vortices appearing in an applied field, and the quantum critical behaviour of the system. We discuss our findings in the light of results of neutron scattering from other groups, on other cuprate systems, and results from other experimental methods, e.g. NMR, μSR, STM, X-ray diffraction, and ARPES. We end with a discussion on the implications of the experimental results for the progress in the general understanding of high-temperature superconductivity. PACS numbers: 61.12.Ex, 74.20.Mn, 74.72.Dn, 75.25.+z, 78.70.Nx. 相似文献