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991.
In the past decades, there was considerable controversy over the Lucas–Washburn (LW) equation widely applied in capillary imbibition kinetics. Many experimental results showed that the time exponent of the LW equation is less than 0.5. Based on the tortuous capillary model and fractal geometry, the effect of tortuosity on the capillary imbibition in wetting porous media is discussed in this article. The average height growth of wetting liquid in porous media driven by capillary force following the [`(L)] s(t) ~ t1/2DT{\overline L _{\rm {s}}(t)\sim t^{1/{2D_{\rm {T}}}}} law is obtained (here D T is the fractal dimension for tortuosity, which represents the heterogeneity of flow in porous media). The LW law turns out to be the special case when the straight capillary tube (D T = 1) is assumed. The predictions by the present model for the time exponent for capillary imbibition in porous media are compared with available experimental data, and the present model can reproduce approximately the global trend of variation of the time exponent with porosity changing.  相似文献   
992.
论文介绍6片不同高宽比的水泥聚苯模壳格构式混凝土墙体在轴压力和水平往复侧推力作用下的试验,分析这种墙体的抗侧强度、刚度和延性等力学性能.试验表明,高宽比大于1的墙体破坏时表现为墙体跟部的单一水平裂缝,其他部位完好;高宽比3∶4的墙体破坏时存在多条通过格构梁柱的斜向裂缝,墙体裂缝分布密集,变形能力好.  相似文献   
993.
During the pneumatic conveying, pulverized coal with different moisture contents may develop substantial difference in flow characteristics, whose cause is not fully understood. This study focused on influence of moisture content on conveying characteristics in an experimental test facility with the conveying pressure up to 4 MPa. The experiments included soft coal and lignite with similar density and particle size. With the increase in moisture content, the mass flow rate decreased for lignite (3.24% < M < 8.18%) but increased at first and then decreased for soft coal (0.4% < M < 6.18%) at same operating parameters. The flowability of soft coal was worse than that of lignite at similar operating parameters and external moisture content. The extremal conveying moisture contents of two coal types were obtained. The particle charge and surface moisture content were investigated to indicate influence mechanism of moisture content on mass flow rate in pneumatic conveying at high pressure. Pressure drop of soft coal was greater than that of lignite for same test section. The conveying phase diagram of dense-phase pulverized coal at high pressure was obtained and the pressure drops through different test sections were compared and analyzed. The bend loss factor rose with the increase in moisture content and was independent of conveying velocity and solid-gas ratio in dense-phase pneumatic conveying at high pressure.  相似文献   
994.
In this paper we obtain a strong invariance principle for negatively associated random fields, under the assumptions that the field has a finite (2 + δ)th moment and the covariance coefficient u(n) exponentially decreases to 0. The main tools are the Berkes-Morrow multi-parameter blocking technique and the Csörg?-Révész quantile transform method.  相似文献   
995.
We give new generalizations of some q-series identities of Dilcher and Prodinger related to divisor functions. Some interesting special cases are also deduced, including an identity related to overpartitions studied by Corteel and Lovejoy.  相似文献   
996.
In the present paper, we investigate the dual Lie coalgebras of the centerless W(2, 2) algebra by studying the maximal good subspaces. Based on this, we construct the dual Lie bialgebra structures of the centerless W(2, 2) Lie bialgebra. As by-products, four new infinite dimensional Lie algebras are obtained.  相似文献   
997.
Cai  Ao  Chavaudret  Claire  You  Jiangong  Zhou  Qi 《Mathematische Zeitschrift》2019,291(3-4):931-958
Mathematische Zeitschrift - We show that if the base frequency is Diophantine, then the Lyapunov exponent of a $$C^{k}$$ quasi-periodic $$SL(2,{\mathbb {R}})$$ cocycle is...  相似文献   
998.
In this paper it is proved that every sufficiently large even integer N satisfying one of the congruence conditions N ≡ 10, 58, 130, or 178(mod 240) may be represented as the sum of one square and nine fourth powers of prime numbers.  相似文献   
999.
Science China Mathematics - Owing to its efficiency in solving some types of large-scale separable optimization problems with linear constraints, the convergence rate of the alternating direction...  相似文献   
1000.
Zhang  Lei  Xu  Chao  Guo  Yaohao  Zhu  Guangpu  Cai  Shiyu  Wang  Xin  Jing  Wenlong  Sun  Hai  Yang  Yongfei  Yao  Jun 《Transport in Porous Media》2021,140(3):713-725
Transport in Porous Media - Pore scale immiscible displacement is crucial in oil industry. The surface roughness of throat is an important factor affecting water–oil interface movement. In...  相似文献   
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