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151.
In this study, we detail a method for estimating the flux-averaged solid fraction of a steady granular flows moving down an
inclined rectangular chute using velocity measurements from along the perimeter cross section, combined with knowledge of
the mass flow rate through the cross section. The chute is 5 cm wide and 150 cm long with an adjustable inclination angle.
Four inclination angles, from 27° to 36° at 3° intervals, are tested. This angle range overlaps the internal friction angle
of the glass beads, which are 4 mm nominal in diameter. Two slender mirrors are installed at the top and the bottom of the
transparent chute to reflect images of the flow down the chute of the two surfaces. This allows photographic recording of
the flow with a PIV imaging system and measurement of the flow depth. The mass flow rate can be calibrated simultaneously
by collecting the accumulated mass at the chute exit. A linear interpolation scheme is proposed to interpolate the volume
flow rate in each section of the chute. Sensitivity analysis suggests that the relative standard deviation of this scheme
is about ±6%, i.e., the resultant solid volume fraction is only moderately dependent on the interpolation scheme for the tested
cases. This is further confirmed by a direct intercepting method. Compared to the sophisticated magnetic resonance imaging
(MRI) or the radioactive positron emission particle tracking (PEPT) methods, the present method is verified as a cost-effective
and nonhazardous alternative for ordinary laboratories. Two distinct groups of streamwise dependence of the solid fractions
are found. They are separated by the inclination angle of the chute and agreed with the internal friction angle. In the experiments
using the two smaller inclination angles, the solid fraction ratios are found to be linear functions of the streamwise distance,
while for the two larger inclination angles, the ratios have a nonlinear concave shape. All decrease with growing downstream
distance. 相似文献
152.
目的:观察用普瑞博思(西沙必利)治疗急性胰腺炎的疗效。方法:不用禁食水及胃肠减压,而口服普瑞博思10mg一日3次,服药后呕吐加服适量本药,同时静点妥布霉素及西米替丁。结果:治疗组进食早,使用解痉镇痛药量少,缓解疼痛快。结论:使用普瑞博思治疗急性胰腺炎,无胃肠减压之痛苦及不便,进食早,缓解疼痛快,住院时间短,费用低。 相似文献
153.
Dopamine was electrochemically oxidized in aqueous solutions and in the organic solvents N,N‐dimethyl‐formamide and dimethylsulfoxide containing varying amounts of supporting electrolyte and water, to form dopamine ortho‐quinone. It was found that the electrochemical oxidation mechanism in water and in organic solvents was strongly influenced by the buffering properties of the supporting electrolyte. In aqueous solutions close to pH 7, where buffers were not used, the protons released during the oxidation process were able to sufficiently change the localized pH at the electrode surface to reduce the deprotonation rate of dopamine ortho‐quinone, thereby slowing the conversion into leucoaminochrome. In N,N‐dimethylformamide and dimethylsulfoxide solutions, in the absence of buffers, dopamine was oxidized to dopamine ortho‐quinone that survived without further reaction for several minutes at 25 °C. The voltammetric data obtained in the organic solvents were made more complicated by the presence of HCl in commercial sources of dopamine, which also underwent an oxidation process. 相似文献
154.
155.
首次采用非连续变形分析 (DDA) ,分别对挖动岩体结构中的“三咬拱”与“咬合梁”结构模式、形态、位移与关键层进行动态模拟。得出一些有意义的结论 相似文献
156.
槲皮素修饰的从层脂膜作为研究抗病毒药物的一种模型体系,用循环伏安法测定了槲皮素在脂膜界面上的氧化还原性质和配位性质。在电位扫描过程中,微量铜离子能催化槲皮素的氧化,当双层脂膜的两侧存在着合适的氧化还原偶时,就会产生跨膜的电子传递。 相似文献
157.
Simultaneous two-dimensional imaging of an unburnt area and a reacting area was performed using laser-induced fluorescence. Acetone was added to fuel as a tracer, and OH radical was used as a marker of the reacting area. A narrow band tunable KrF excimer laser (248 nm) was employed to excite acetone and OH simultaneously. Two intensified CCD cameras with different wavelength filters were used to detect these two kinds of species respectively. Detecting 294-314 nm (A-X (3, 2), etc.) for OH and 335-410 nm for acetone, we obtained images of each species without interference of a signal from the other. The method was also successfully applied to flames in a pressurized combustion chamber under the pressure of 0.5 MPa. 相似文献
158.
Y. Tai Y. Ochi F. Ohashi K. Tajiri J. Murakami M. Daté S. Tsubota 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,34(1-3):125-128
We have prepared titania aerogel and titania-coated silica aerogel incorporating thiol-capped Au nanoparticles. Both composite materials showed high CO oxidation activity after they were calcined at 673 K. Compositional and morphological changes driven by calcination were evaluated with thermogravimetry and X-ray diffractometry. From the results, it was suggested that the nanoparticles transformed from a faulted to a near-regular FCC structure presumably in concert with the formation of firm contacts between the nanoparticles and the gel substrates. While the diameters of the Au particles in the titania aerogel considerably increased upon calcination, those in the titania-coated silica aerogel were almost unchanged. As a consequence, the latter composite aerogel showed higher activity for oxidation of CO. 相似文献
159.
160.
采用高压脉冲电絮凝法处理印染废水 总被引:3,自引:0,他引:3
根据安徽省枞阳毛巾厂印染废水处理工程实例 ,探讨采用高压脉冲电絮凝法处理印染废水的工艺方法及效果 相似文献