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151.
Monocrystalline 6H-SiC thin films have been epitaxially grown on off-axis 6H-SiC {0001} substrates in the temperature range
of 1623–1873 K via chemical vapor deposition. The growth rate was a strong function of the growth temperature and the reactant
gas concentration. The activation energies for growth were 64 kJ/mole and 55 kJ/mole for the (0001) Si face and the (0001)
C face, respectively. The concentration of growth pits in the films increased as a function of decreasing deposition temperature,
increasing concentration of reactant gases and increasing off-axis orientation. Beta-SiC islands were also observed in the
epilayers when the (SiH4 + C2H4)/H2 ratio was ≥2.5:3000. 相似文献
152.
青钢应从我国钢铁工业的实际出发,在“九五”期间,遵循量力而行的原则,采取两步走的方法,于1998上和2000年分别达到年产83万t和117万t钢的综合生产能力。主要措施是:优化工艺结构,消除二次化铁炼钢;优化炼铁系统装备结构;推进炼钢技术进步,提高连铸比,并以市场为导向,优化产品结构。 相似文献
153.
The pressure variations during polymer flooding of oil reservoirs for oil recovery projects can be used to analyze the flow in the reservoir which is especially useful for the partially perforated reservoirs. This paper presents a relationship between the viscosity and the shear rate which is similar to forms developed for radial flow (Odeh, A. S., Yang, H. T. ([1979]). SPEJ. AIME (Jun.) 155). The power-law viscosity model is used to give the variation of the fluid viscosity with the spherical radius for a mathematical model of unsteady spherical flow for non-Newtonian fluids with wellbore storage and skin. An analytical solution for the wellbore pressure responses derived in Laplace space is used to analyze the behavior characteristics at early and later times to interpret the well-test parameters. The pressure variations are similar to those for a Newtonian fluid at the early times, but at later times, the variation of the viscosity with the power-law exponent is important, so the pressure response differs from that for a Newtonian fluid. The solution has significance for interpreting well test parameters for non-Newtonian spherical flow. 相似文献
154.
某含砷浮选金精矿的细菌氧化预处理-氰化提金试验研究 总被引:4,自引:0,他引:4
云南省某含砷难浸金精矿,常规氰化金浸出率仅为26.17%,通过采用细菌氧化预处理后,金浸出率达到98.25%,获得了非常理想的试验指标。 相似文献
155.
Zhen Wang 《Applied Composite Materials》1995,2(4):257-264
A bimodal Weibull distribution function was applied to analyse the strength distribution of glass fibre bundles under tensile impact. The simulation was performed using a one-dimensional damage constitutive model. The results show that there were two concurrent flaw populations in the fracture process. The regression analysis using the bimodal Weibull distribution function was in good agreement with experiment. 相似文献
156.
泡沫铝的动态压缩性能和吸能性研究 总被引:9,自引:0,他引:9
通过测量泡沫铝在动态和准静态压缩条件下的应力 -应变曲线 ,研究了泡沫铝的准静态和动态压缩行为以及不同应变条件下的吸能性 ,并对其应变率效应进行了分析。结果表明 ,在高应变速率和准静态压缩下 ,泡沫铝的σ -ε曲线均表现出弹性变形段、平缓段和密实段三阶段特征 ;泡沫铝的压缩性能具有明显的应变速率敏感性 ,随应变速率的提高 ,流动应力上升 ,吸能性升高 相似文献
157.
158.
材质对蜂窝纸板缓冲性能的影响 总被引:2,自引:1,他引:1
对两种不同材质的蜂窝纸板静态应力应变性能和动态缓冲结果进行了比较分析。讨论了蜂窝纸板力学性能对应变速度的敏感性及两种纸板的缓冲性能差异。缓冲试验结果表明。在不同的冲击应变率下蜂窝纸板的材质影响蜂窝纸板缓冲性能。 相似文献
159.
《Drying Technology》2007,25(5):831-839
Residence time distributions for an aqueous solution of 10% sodium chloride in a spouted bed dryer of inert particles were determined using the stimulus-response technique. Glass and polyethylene beads with diameters 2.6 and 3.4 mm were used as inert bodies in a cylindrical column of 14.0 cm diameter and 60° conical base. The effects of inert bodies load, air, and paste flow rates on the mean residence times and RTD were determined following 23 factorial designs. The RTD could be correlated to the perfect mixing cell model with R2 varying from 0.8684 to 0.9815. The mean residence times in CSBD varied from 10.8 to 13.9 and 10.7 to 13.3 min for glass and polyethylene beads, respectively. For both inert particles, mean residence times increased with bed height and decreased with paste feed rates. Also, terms of interaction among the factors were significant in some cases, showing a complex behavior of paste residence times. Equations obtained by response surface regression could predict mean residence times on glass and polyethylene beads with deviations lower than ±10%. 相似文献
160.
Yu. S. Gorbunov A. G. Ageev R. V. Vasil’eva B. M. Korol’kov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2007,41(3):166-170
A system for the direct measurement of steam flow in steam lines after a steam generator, which utilizes a special design
of pneumometric tubes and a computing unit that accounts for variation in steam pressure, has been developed to improve the
quality of water-level regulation in the steam generators of VVéR-1000 power-generating units in the stationary and transitional
modes. The advantage of the pneumometric tubes consists in their structural simplicity, high erosion resistance, and absence
of irrevocable losses during measurement of steam flow. A similar measurement system is used at foreign NPP. The measurement
system in question has been placed in experimental service at the No. 3 unit of the Balakovo NPP, and has demonstrated its
worthiness. This measurement system can also be used to determine steam flow in the steam lines of NPP units with VVéR-1000
and VVéR-440 reactors, and PBMK-1000 power-generating units.
__________
Translated from élektricheskie Stantsii, No. 3, March 2007, pp. 23–26. 相似文献