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排序方式: 共有846条查询结果,搜索用时 734 毫秒
81.
82.
We report laser oscillations in Cd II on 4d
95s
2
2
D
5/2 − 4d
105p
2
P
3/2 transition at 441.6 nm using laser produced tungsten plasma as a pumping source. Mach Zehnder interferometer is used to measure
electron density. Design and working of the crossed heat pipe used in the studies is discussed. 相似文献
83.
84.
以苯-乙醇为溶剂,在对煤气管道沉积物提取,分离后,采用25m*0.24mmI.D.的石英毛细管OV-101柱进行了GC,GC-MS分析,鉴定出19种有机成分,并用归一法作了定量分析,并用采用IR、点滴试验等方法对其无机物作了定性鉴定。 相似文献
85.
广义二阶流体管内轴向流动 总被引:4,自引:1,他引:3
在流体的本构关系中引入分数阶导数运算,对于介于粘性与弹性之间的流体的描述更具有合理性。本文将这种关系引入二阶流体,研究其管内轴向流动。我们先求出了1/2阶导数的解析解,用以验证Laplace数值反演的CRUMP方法的有效性。然后用CRUMP法分析二阶流体管内轴向流动的特征。分析表明粘弹性特征越明显的流体,其速度与应力对分数导数的阶数越具有敏感性。 相似文献
86.
Narakorn Srinil 《International Journal of Non》2007,42(1):180-195
This study aims at comparing non-linear modal interactions in shallow horizontal cables with kinematically non-condensed vs. condensed modeling, under simultaneous primary external and internal resonances. Planar 1:1 or 2:1 internal resonance is considered. The governing partial-differential equations of motion of non-condensed model account for spatio-temporal modification of dynamic tension, and explicitly capture non-linear coupling of longitudinal/vertical displacements. On the contrary, in the condensed model, a single integro-differential equation is obtained by eliminating the longitudinal inertia according to a quasi-static cable stretching assumption, which entails spatially uniform dynamic tension. This model is largely considered in the literature. Based on a multi-modal discretization and a second-order multiple scales solution accounting for higher-order quadratic effects of a infinite number of modes, coupled/uncoupled dynamic responses and the associated stability are evaluated by means of frequency- and force-response diagrams. Direct numerical integrations confirm the occurrence of amplitude-steady or -modulated responses. Non-linear dynamic configurations and tensions are also examined. Depending on internal resonance condition, system elasto-geometric and control parameters, the condensed model may lead to significant quantitative and/or qualitative discrepancies, against the non-condensed model, in the evaluation of resonant dynamic responses, bifurcations and maximal/minimal stresses. Results of even shallow cables reveal meaningful drawbacks of the kinematic condensation and allow us to detect cases where the more accurate non-condensed model has to be used. 相似文献
87.
Friction and heat transfer in drag-reducing surfactant solution flow through curved pipes and elbows
A study of drag-reducing flow in curved pipes was conducted. In contrast to earlier studies we show that if we use a modified definition of drag reduction that includes only the turbulence effects, we observe indeed the same level of drag reduction in both coiled and straight pipes. More complex results showing reduced drag reduction compared to curved pipes were achieved with elbows. Two elbows of different size and type were tested in turbulent flow of both water and drag-reducing surfactant solution. A more elaborate analysis was conducted for a half-inch threaded elbow with a ratio of curvature radius to diameter of 1.2. The pressure drop and heat transfer were measured in a section downstream from the elbow over a distance of x/D = 130 in order to investigate the hydrodynamic and thermal developments of the flow. The pressure drop coefficient of the elbow was calculated for water and a surfactant solution, based on the total increase in pressure drop in the system due to the presence of the elbow. For a larger welded elbow of 6″ diameter some drag reduction was measured for the surfactant solution. 相似文献
88.
On the extended linear complementarity problem 总被引:8,自引:0,他引:8
M. Seetharama Gowda 《Mathematical Programming》1996,72(1):33-50
For the extended linear complementarity problem (Mangasarian and Pang, 1995), we introduce and characterize column-sufficiency,
row-sufficiency andP-properties. These properties are then specialized to the vertical, horizontal and mixed linear complementarity problems.
This paper is dedicated to Professor Olvi L. Mangasarian on the occasion of his 60th birthday. 相似文献
89.
This paper presents a two-dimensional model for the analysis of the pressure transient of a two-phase homogeneous bubbly mixture flowing in a pipeline and the numerical integration using the centre implicit method (CIM). Experiments were conducted to confirm the proposed sonic speed equation of an air–water mixture for an air concentration of less than 1%. The 2D CIM model is compared with the method of characteristics (MoC) for a two-phase bubbly flow in a pipeline. The comparisons show that the proposed 2D CIM model generally gives good agreement with the method of characteristics. 相似文献
90.
热管技术已在电子设备散热领域得到广泛应用。热管的传热能力虽然很大,但不能无限加大热负荷。文中讨论了热管的主要极限如沸腾极限、毛细极限、粘性极限、声速极限、携带极限等的理论表达式,就一种实验用微槽平板热管进行了理论计算,得出了毛细极限是实验热管主要传热极限的结论。 相似文献