开采沉陷土体变形与孔隙水压相互作用研究进展

本文通过实验、实测和理论分析研究了开采沉陷土体变形与孔隙水压力之间的相互作用,结果表明,随着开采的进行,土体的应力变形发生变化造成了超静孔隙水压力的产生和消散,反映在土体变形上出现随开采时间延续而发展的附加压缩和膨胀变形,这种压缩或膨胀在土体的不同部位相互叠加,有时还叠加了底部含水层水位下降引起的地面下沉。这些结果揭示了厚松散含水层地区开采沉陷特殊性的机理,对开采沉陷预测及水体下采煤具有重要意义。     

Simulation of Three-Phase Displacement Mechanisms Using a 2D Lattice-Boltzmann Model

Using a numerical technique, known as the lattice-Boltzmann method, we study immiscible three-phase flow at the pore scale. An important phenomenon at this scale is the spreading of oil onto the gas–water interface. In this paper, we recognize from first principles how injected gas remobilizes initially trapped oil blobs. The two main flow mechanisms which account for this type of remobilization are simulated. These are the double-drainage mechanism and (countercurrent) film flow of oil. The simulations agree qualitatively with experimental findings in the literature. We also simulate steady-state three-phase flow (fixed and equal saturations) in a small segment of a waterwet porous medium under both spreading and nonspreading conditions. The difference between the two conditions with respect to the coefficients in the generalized law of Darcy (which also includes viscous coupling) is investigated.     

大孔树脂孔结构的测定

介绍了大孔树脂比表面积,孔容,平均孔径及孔径分布等孔结构参数的测定方法,对各参数的不同测定方法进行了分析,比较。通过作者的工作,对大孔树脂的孔结构测定及测定中需要注意的问题进行了讨论,对各种方法的特点进行了总结。     

饱和砂土振动扎隙水压力理论与应用研究进展

本文简要回顾了地震、波浪等引起的往返载荷作用下饱和砂土孔隙水压力理论与应用的研究历史和实践背景,并从影响因素、计算理论与应用等较广泛的范围,就目前国内外对饱和砂土振动孔隙水压力问题的研究现状作了较系统的评述,最后讨论了有待进一步研究的问题。      

Continuous‐Bed Columns Containing Sol‐Gel Bonded Packing Materials for Capillary Electrochromatography

Sol‐gel bonded packing materials in continuous‐bed columns have been prepared for capillary electrochromatography (CEC). Three packing materials were investigated: small‐pore Spherisorb ODS1 (3 μm, 80 Å) with octadecyl as stationary phase, small‐pore mixed‐mode Spherisorb ODS/SCX (3 μm, 80 Å) with octadecyl and propyl sulfonic acid as stationary phases, and large‐pore Nucleosil ODS (7 μm, 1 400 Å) with octadecyl as stationary phase. The characteristics of these columns were compared in terms of electroosmotic flow, efficiency, inertness, and retention factors. In contrast to columns containing sol‐gel bonded ODS, columns containing sol‐gel bonded mixed‐mode ODS/SCX generated nearly pH independent electroosmotic flow (EOF) over pH 2–9. Columns containing sol‐gel bonded large‐pore ODS produced nearly three times lower reduced plate height than those containing small‐pore ODS. Efficiencies of 220,000 plates per meter and 175,000 plates per meter were obtained from columns containing sol‐gel bonded 7 μm, 1 400 Å ODS and columns containing sol‐gel bonded 3 μm, 80 Å ODS, respectively, which are among the highest reported efficiencies for continuous‐bed columns. In CEC, over one million plates per meter and pH independent EOF are expected from continuous‐bed columns containing sol‐gel bonded 1.5 μm particles with large pores and mixed‐mode stationary phases.     

A Study of Porous and Surface Properties of Nickel-Molybdenum Catalyst Incorporated on Alumina Modified with Sodium and Magnesium Ions

A series of nickel-molybdenum samples supported on alumina modified with sodium or magnesium ions was studied by the BET method, differential thermal analysis (DTA) and IR spectroscopy to determine their surface properties, pore volume and distribution. Modification with sodium and magnesium ions causes a decrease of the surface area of the nickel-molybdenum catalysts. The decrease proceeds with increasing concentration of the modifying ions. Incorporation of these ions does not change the type of catalyst pores (the ink-bottle or bottle types), yet it affects the size and distribution of pores. It was found that sodium ions prevent from the formation of aluminum molybdate, while magnesium ions increase the thermal stability of the catalyst.     

Quantification of Porous Properties of Shear Crystallized Lipids

The aim of this study was to investigate the impact that shear and composition have on the structural properties associated with the porous phases of lipids. To accomplish this aim, we developed eight main crystallized samples using cocoa butter (CB) or trilaurin (TL) in the presence or absence of monostearate (M) (5% w/w). The samples were sheared at 500 s⁻¹ using random (RS) or laminar (LS) shear at a cooling rate of 2 °C/min. Using the maximal ball (MB) algorithm, several empirical void measurements such as connectivity (z), pore and throat volume weighted radii (R₄₃), and void fraction (v) were quantified using 3D X-ray microcomputed tomography images. Most void features were identified as micropores (R ≥ 10 μm) possibly originating from the crystallization process and post-process crystal growth. Likewise, depending on the applied treatments, mechanisms impacting void formation were found to produce noticeable variation in v (0.019 to 0.139) and to determine whether void morphology was spherical, irregular, and/or highly connected.     

多孔TiC陶瓷的制备、性能及机理研究

以TiO2和炭黑为反应物,TiC为添加物,通过反应烧结法制备出多孔TiC陶瓷.研究了TiC的添加量对晶粒大小、孔径尺寸、开气孔率及抗弯强度的影响.研究结果表明:随着TiC的添加量从0;增大到100;,反应生成TiC的粒径从0.17μm增大到0.71μm,孔径尺寸从0.15μm增大到1.51μm,开气孔率从78;持续降到38;,抗弯强度先增加后减小,添加量为80;时最高(86 MPa).TiC生长机理主要是由于添加的TiC使TiO2周围的碳含量减少,从而导致反应生成TiC的熔点降低,扩散能力提高,晶粒粒径增大.     

准单畴YBCO块材当中磁悬浮力不均匀性研究

顶部籽晶熔融织构准单畴Y1B2C3O7-δ中磁悬浮力密度与籽晶位置的关系进行了深入研究.经研究发现在液氮温度下磁悬浮力密度大小随位置变化,在离顶部籽晶3 mm的地方达到最大值,换句话说就是在第二块薄片中具有最大磁悬浮力密度.这种现象可以用晶体生长和吸氧的过程的相互作用来解释.我们提出一个模型,在这个模型中Y211粒子的分布导致的小孔微结构降低了有效感应电流环的大小,从而相当于降低了单畴的有效尺寸,导致磁悬浮力的大小.从研究中发现纵向微裂纹对磁悬浮力的影响最为明显.这个结果对于顶部籽晶熔融织构准单畴的基础研究和制造有很大的意义.     

Porous Organic Salts Composed of Terphenyl Sulfonic Acid and Their Bottleneck Designability

Porous organic salts (POSs) are constructed through a strong charge-assisted hydrogen bond between sulfonic and amino groups. The molecular design of sulfonic acid, the linker part, enables various porous structures. In the current work, we synthesized p-terphenyl-4,4’’-disulfonic acid (TPDS), whose molecular structure can be easily modified by organic synthesis. Combining of TPDS and bulky tri-p-tolylmethanamine (TPMA-Me), which has three methyl groups at each para-position of the phenyl groups of triphenylmethylamine (TPMA), gave POS with one-dimensional pore channels having two different types of bottlenecks. The central benzene ring of TPDS is exposed on the surface of the pore. Therefore, we combined 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzenesulfonic acid (BTDBS) containing 2,1,3-benzothiadiazole (BT) with TPMA-Me, and successfully constructed a one-dimensional pore channel with a bottleneck of 3.5 Å, by exposing BT to the surface of the pore. BTDBS/TPMA-Me exhibited a large adsorption/desorption hysteresis of nitrogen because of the bottleneck, electronic state of BT, and larger oxygen adsorption than the isostructural TPDS/TPMA-Me. Systematic and intended modulation of the pore structure of POS based on the modification of sulfonic acid was demonstrated, and for the first time, we established a precise design methodology for a one-dimensional pore channel with a bottleneck and high crystallinity in metal-free porous organic materials.