一种CO_2开关型粘弹性可逆流体的制备与性质

采用缩醛法对三乙烯四胺进行脒基化,获得一种二元脒基化合物,与十二烷基苯磺酸钠混合,制得粘弹性流体,考察了CO2、混合液配比、温度对流体粘弹性的影响。结果表明,在35℃下,当二元脒基化合物与十二烷基苯磺酸钠的摩尔比为1∶1.2时,溶液的粘弹性最佳,显示出蠕虫状胶束的特征,混合溶液的网络结构。     

压裂酸化用粘弹性表面活性剂溶液研究进展

粘弹性表面活性剂溶液的高表面活性及独特的流变特性可以作为理想的压裂、酸化、砾石充填等增产改造以及三次采油措施流体。详细介绍了粘弹性表面活性剂流体的组成、制备与表征方法,阐述了典型粘弹性表面活性剂流体流变特性研究现状;概述了粘弹性表面活性剂流体在压裂、酸化等增产措施中的应用进展,并指出了粘弹性表面活性剂流体矿场推广应用尚需解决的问题。     

十六烷基三甲基溴化铵-对甲苯磺酸钠溶液流变性研究

十六烷基三甲基溴化铵与对甲苯磺酸钠按摩尔比1∶1复配后可形成粘弹性极好的流体。常温下当剪切频率高于0.863 2 rad/s时,粘性模量值开始超过弹性模量;在剪切频率范围内,流体符合Cole-Cole图的模型;复合粘度与变剪切速率具有相近的值,外推得溶液零剪切粘度为10.5 Pa·s,溶液为良好符合麦克斯韦模型的粘弹性流体。     

十六烷基三甲基溴化铵-对甲苯磺酸钠溶液流变性研究

十六烷基三甲基溴化铵与对甲苯磺酸钠按摩尔比1∶1复配后可形成粘弹性极好的流体。常温下当剪切频率高于0.863 2 rad/s时,粘性模量值开始超过弹性模量;在剪切频率范围内,流体符合Cole-Cole图的模型;复合粘度与变剪切速率具有相近的值,外推得溶液零剪切粘度为10.5 Pa·s,溶液为良好符合麦克斯韦模型的粘弹性流体。     

N-长链烷基脒基碳酸氢盐表面活性的研究

以N-长链烷基脒为原料,在CO2氛围下制备得到N-长链烷基脒基碳酸氢盐。系统研究其表面活性发现：N-长链烷基脒基碳酸氢盐具有很好的表面活性,γcmc在20.5～32.3 mN/m之间;随着疏水链长的增加,N-长链烷基甲脒碳酸氢盐和N-长链烷基乙脒碳酸氢盐溶液的cmc和γcmc均逐渐降低,但N-长链烷基甲脒碳酸氢盐的cmc和γcmc均比N-长链烷基乙脒碳酸氢盐高;30～70℃时,N-长链烷基脒基碳酸氢盐溶液的表面张力均随温度的升高先降低后增大,热重分析表明这是由于在高温下脒盐会发生分解,溶液中的脒盐会部分转化成为中性脒,使得溶液中的脒盐浓度降低,表面张力变大。     

新的分子热力学模型及其应用(Ⅰ)——一种新的分子径向分布函数表达式的提出及其检验

根据液体的性质、实验现象及统计力学原理,根据总相关函数h(r)与阻尼振动之间存在的相似性,经过分析和数学处理得到了非电解质溶液径向分布函数表达式.应用该式于LJ流体、液态氩以及二元混合溶液体系,计算结果与文验、计算机模拟结果吻合较好.     

新的分子热力学模型及其应用(Ⅰ)——一种新的分子径向分布函数表达式的提出及其检验

根据液体的性质、实验现象及统计力学原理,根据总相关函数h(r)与阻尼振动之间存在的相似性,经过分析和数学处理得到了非电解质溶液径向分布函数表达式.应用该式于LJ流体、液态氩以及二元混合溶液体系,计算结果与文验、计算机模拟结果吻合较好.     

酯基Gemini型季铵盐表面活性剂与AEO9的复配体系研究

通过考察酯基Gem in i型季铵盐表面活性剂Ⅱ-10-n(n=3,4,6)与十二烷基聚氧乙烯(9)醚(AEO9)的复配体系的表面活性发现,复配体系的临界胶团总浓度CMCT值介于二元复配体系中各组分的临界胶团浓度CMC01和CMC02之间。当溶液中含有少量AEO9时(在溶液体相中的摩尔分数α2=0.1),混合胶团中AEO9的摩尔分数均已超过0.35;随着溶液中AEO9含量的增大,混合胶团中逐渐以AEO9为主成分。复配体系的混合胶团聚集数介于二元复配体系中各组分的胶团聚集数之间,随着溶液中酯基Gem in i型季铵盐表面活性剂含量的增加,混合胶团聚集数逐渐减少。     

基于正规溶液理论计算三元混合表面活性剂的临界胶束浓度

随着溶液pH的降低,TX-100/N,N-二甲基十二烷基氧化胺二元表面活性剂混合体系变为三元表面活性剂混合体系;利用滴体积法测定了不同pH时该混合体系的临界胶束浓度,并利用正规溶液理论计算了该三元表面活性剂混合体系的临界胶柬浓度,计算结果在一定范围内与实验较好地相符.     

气体在混合溶液中溶解度的分子热力学计算

开发出一个分子热力学模型来预测低压下难溶于溶剂且不与溶剂发生反应的气体在二元混合溶液的溶解度,混合物中含有缔合作用成分及溶剂化作用成分,即形成配位化合物。在该模型中,Gibbs能为三个等温混合过程的和。溶质的偏摩尔过量Gibbs能由两部分组成,即化学和物理贡献。为了验证该模型的准确性,将该模型用于计算氮气在丙酮和氯仿混合物的溶解度。考虑实验的不确定度,氮气在二元混合溶液中的溶解度与实验数据吻合良好。     

Extraction into a flow of a fluid with a velocity gradient

Unsteady extraction from a system of semi-infinite capillaries to the flow of a fluid with a linear velocity gradient is studied. An assumption that the diffusion in the flow is a quasi-steady-state process is taken to obtain a linear equation for the local mass flux from the pore space, which involves fractional derivatives with respect to time and flow coordinate. Limiting solutions for the total diffusion flux at small and large times that cover the entire time interval are found.     

Electrolytes: From a Thorn Comes a Rose,and from a Rose,a Thorn

In this article we take a stroll through the metaphorical rose garden, part of the flower garden, that is electrochemical storage systems. We take a closer look at batteries as the center‐pieces – the roses – and especially at the system component of batteries, the electrolyte and its development, throughout history. Just as a rose can only develop its unique beauty when taken good care of and provided with clean water and suitable nutrients, a battery cell cannot function without its electrolyte; the seemingly trivial component that has to juggle a multitude of requirements in order to make batteries truly bloom.     

Propagation of a burning front over a condensed material from a focus

Measured propagation speeds are given for the combustion front in a blind gap in a condensed substance, which are related to gap height and mean pressure. The front may propagate monotonically, which is characteristic of relatively high pressures and wide gaps, or as a result of additional burning foci arising at a certain distance from the main front. At low pressures and particularly with small gap heights, the front propagates in an unstable fashion over the surface.Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 28, No. 4, pp. 49–53, July–August, 1992.     

Mesomorphic transitions in a mixture of a flexible and a semi-rigid polymer

Phase studies on a mixture of two polymers are presented, one of which is mesomorphic. We have systematically examined the influence of the molecular weight of the flexible polymer (including the oligomers) and of the semi-flexible polymer. In addition to the effect of the molecular weight, specific interactions are important for compatibility and formation of a homogeneous mesomorphic phase. The nature of this phase is demonstrated to be cholesteric and the pitch is determined.     

When is a Beam a Plate?

Formulas associated with simple beam or plate theories are used extensively in structural design, to determine You's modulus, and to determine fracture strength of brittle nonmetallic materials. The question may arise as to whether the proper ratio of beam-width-to-beam-depth is such that the bent structural element can be considered as a beam and, if not, what is the correction factor that should be used with the simple beam formula. These questions are answered for a range of structural metallic and brittle nonmetallic materials.     

Laminar flow deformation of a droplet adhering to a wall in a channel

We study the deformation of oil droplets of varying viscosity adhering to a solid, rigid wall in a rectangular channel induced by a pressure-driven, laminar flow of water. Our experimental investigation involves the systematic study of the effects of initial droplet volume, flow rate and viscosity ratio on the various modes of droplet motion and deformation; this is performed via direct visualisation of the flow in a glass cell using a high-speed camera. Our results are used to construct flow maps that delineate the critical conditions for droplet ‘sliding’, ‘crawling’ and detachment from the channel wall as a function of system parameters. Comparisons of our experimental results with numerical predictions obtained using a procedure based on the diffuse-interface method yield reasonably good agreement for certain flow regimes.     

Detonation of a Column of a Chemically Active Bubbly Medium in a Liquid

The problem of a detonation wave propagating in a cylindrical column of a chemically active bubbly medium screened by a liquid from the tube walls is formulated and numerically solved within the framework of the Iordanskii–Kogarko two-phase model with allowance for energy dissipation due to acoustic radiation of bubbles. The wave structure of the reaction zone and the detonation velocity of the bubbly medium column are calculated. It is found that the self-sustaining wave can propagate with a velocity greater than the velocity of one-dimensional bubble detonation by a factor of 1.5–2.5.