The role of ion-membrane interactions in fast and selective mono/multivalent ion separation with hierarchical nanochannels

Precise control over the nanofluid behavior of polyelectrolyte-based membranes is a primary step toward understanding the structure-morphology-property relationships to ultimately determine the mass transfer characteristics. In this study, a high-performance multistacked polyelectrolyte-based cation exchange membrane (CEM) with a heterogeneous structure and versatile surface chemistry was developed to achieve selective ion conductance. The self-assembled CEM can facilitate ion permeation with fluxes of 2.9 mol m⁻² h⁻¹ for K⁺ and 0.22 mol m⁻² h⁻¹ for Mg²⁺, reaching a mono/multivalent ionic selectivity of up to 13, outperforming mono/divalent fractionation when compared with state-of-the-art membranes. Molecular dynamic (MD) simulations illustrated the ionic transport trajectory in hierarchical channels with angstrom-scale cavities using multilayered CEMs. Both the experimental measurements and theoretical simulations indicated that ionic fractionation was associated with a large disparity in the energy barrier between mono/multivalent cations, which was the primary origin of the differences in the ion dehydration-rehydration processes in the angstrom-confinement membrane ion channels.     

膜技术在盐湖提锂中的进展和展望

随着新能源产业的快速发展,卤水锂资源开发已成为世界范围战略性新兴产业发展的重要内涵。膜分离技术,因其优异的一/二价离子分离性能、良好的环保和经济性,已成为中国高镁锂比盐湖卤水提锂的主流工艺。归纳分析了膜分离技术在卤水体系中的分离机理、研究进展及未来发展方向。新型高性能锂离子分离膜的持续研究发展,必将加速提升中国卤水锂资源的开发水平。     

注流孔结构对中间包流场影响的物理模拟

针对某钢厂十流中间包紊流抑制器注流孔结构不合理引起流场分布差、各流铸坯质量不均的问题,运用相似原理,使用相似比为1:3的物理模型进行水模型实验,设计不同的注流孔结构研究流体在中间包的平均停留时间曲线及流场显示特征,明晰注流孔结构对中间包流场的影响规律,优化紊流抑制器注流孔结构,达到中间包流场优化及浸入式水口各流一致性提高的目标。结果表明,长距离多流中间包在无堰坝结构条件下,紊流抑制器的注流孔内径尺寸、数量及开孔方向对中间包流场都有影响,注流孔内径的影响最为显著,数量次之。设计的最佳注流孔内径由原型的53 mm缩小至30 mm,死区比例由54.05%降至34.69%,F曲线最大标准差由0.0154降低至0.0035,中间包流场得到改善,各流一致性显著提高。当注流孔数量由1个增加至3个,死区比例由34.69%增大至46.05%,F曲线最大标准差由0.0035增大到0.0062,注流孔数目越多,流场死区比例反而越大,各水口流场的一致性越差。对长距离多流中间包,建议主要通过适当改变注流孔内径及减少孔数来改善中间包流场,提高各流一致性。     

Obtaining the kinetic function of depolymerization from evolving molecular weight distribution data–an inverse problem

Depolymerization of macromolecules is generally regarded as a first order process with a kinetic function that depends on the molecular weights of the fragmenting molecule and fragmentation products. This article describes a computation scheme for obtaining the kinetic function from observed molecular weight distribution (MWD) data. The integro‐differential equation used by most investigators to compute MWD with some assumed kinetic function is reformulated as an inverse problem in which the kinetic function is treated as the unknown to be extracted from evolving MWD data. A numerical procedure based on two consecutive applications of Tikhonov regularization is developed to solve this inverse problem. It gives the kinetic function as the solution of a set of linear algebraic equations. Implementation of this procedure is described in full and its performance is assessed by applying it to simulated MWD data. A number of issues associated with discretization and regularization are discussed. © 2012 American Institute of Chemical Engineers AIChE J, 59: 912–922, 2013     

开发和利用军事文化资源,提升安徽文化软实力

论文分析了安徽境内军事单位蕴藏的军事文化资源概况,概括了军事文化资源对提升安徽文化软实力中的积极作用,探讨了开发与利用军事文化资源的主要途径。     

S-PFEL用三镜准光腔系统的研究

介绍了史密斯——帕塞尔效应慢波自由电子激光(S-PFEL)用三镜准光学谐振腔系统;利用光学谐振腔衍射理论,采用面对称近似又坐标旋转的方法建立模型,对胜场特性进行分析,给出工作方程,完成数值模拟,并在毫米波段进行冷测实验。分析及实验结果表明,给出的方法可用来有效、快捷的分析和设计面对称三镜准光学谐振腔系统。设计的模型已成功用于S-PFEL实验。     

Ras-GRF1基因敲除小鼠的行为学研究

Ras基因广泛存在于自然界中,其控制的Ras-GRF1蛋白在细胞信号传导,在细胞分化与生长过程中起着极其重要的作用。已有研究表明,Ras基因与信号通路和学习记忆功能密切相关。本实验利用行为学研究敲除Ras-GRF1基因的小鼠在学习记忆上与野生老鼠的差异,通过Morris水迷宫等实验发现Ras-GRF1基因敲除小鼠的学习记忆能力弱于野生型小鼠。     

有机凝胶调剖剂强度的剪切恢复性能研究

采用动态剪切实验研究了两种有机凝胶类调剖剂强度的剪切恢复性能,通过测定不同条件下凝胶体系的储能模量耗能模量和相位角的变化,分析了在聚交比一定的条件下,聚合物浓度、温度以及交联剂类型对凝胶剪切后强度恢复性能的影响。结果表明:在一定的应力下,随着聚合物浓度的增加,凝胶的成交点频率向低频移动;相同聚合物浓度和放置时间下,有机金属交联型调剖剂的强度大于有机酚醛交联型调剖剂;同种凝胶体系,在聚交比一定的条件下,浓度高时体系强度的剪切恢复性能好;对于两种凝胶体系来说,温度升高使得体系的剪切恢复性能下降;有机金属交联的凝胶体系剪切恢复能力高于有机树脂交联的凝胶体系。     

提高相位式激光测距分辨率的一种设计方法

叙述一种采用相位式激光测距提高测距分辨率的方法,给出采用相位式进行激光测距的原理,提出了小型相位式激光测距机的设计方案及相位鉴别方法.着重对精密检相电路进行了较为深入的分析和讨论.     

Key Frame Extraction of Surveillance Video Based on Fractional Fourier Transform

With the vigorous development of national infrastructure construction and public information construction, video surveillance systems have gradually penetrated various fields. The current key frame extraction technology has inadequate target details and inaccurate judgment of local actions. Addressing this problem, a key frame extraction method based on fractional Fourier transform is proposed. This method obtained the phase spectra information of different orders by performing fractional Fourier transform on the surveillance video frames. Next, the method designed an adaptive algorithm based on the golden section point to select the transformation order.Then, the phase spectrum information of two adjacent frames was used to characterize the changes in the global and local motion states of the target. The final step was to extract key frames based on this. Experimental results show that, compared with the previous methods, the key frames extracted by the method proposed in this paper can correctly capture the changes in the global and local motion states of the target.