Coupling effects of depletion interactions in a three-sphere colloidal system

In a three-sphere system, the middle sphere is acted upon by two opposite depletion forces from the other two spheres. It is found that, in this system, the two depletion forces are coupled with each other and result in a strengthened depletion force. So the difference of the depletion forces of the three-sphere system and its corresponding two two-sphere systems is introduced to describe the coupling effect of the depletion interactions. The numerical results obtained by Monte-Carlo simulations show that this coupling effect is affected by both the concentration of small spheres and the geometrical confinement. Meanwhile, it is also found that the mechanisms of the coupling effect and the effect on the depletion force from the geometry factor are the same.     

高场不对称波形离子迁移谱快速检测水样中苯含量

建立了高场不对称波形离子迁移谱(FAIMS)检测水中苯含量的分析方法。研究了不同分离电压(Dispersion voltage,DV)下的苯标准谱图,获得用于苯识别的非线性函数二阶α2及四阶α4系数值分别为-3.8×10-5Td-2和5.1×10-8Td-4;通过平衡灵敏度与分离度,得到用于苯识别的最佳分离电压为800 V;通过不同质量浓度(0.08~0.64 mg/L)的苯样品与苯离子信号强度的关系,确定高场不对称波形离子迁移谱(FAIMS)对水中苯的检出限为0.89μg/L,远优于国家饮用水中苯浓度的限值10μg/L。本研究为水中苯检测提供了一种快速、高灵敏的方法。     

Depletion interactions in cylindric pipeline

In a colloidal system confined by a small cylindric pipeline, the depletion interaction between two large spheres is different to the system confined by two plates, and the influence on depletion interaction from the pipeline is related to both the size and shape of it. In this paper, the depletion interactions in the systems confined by pipelines of different sizes or different shapes are studied by Monte Carlo simulations. The numerical results show that the influence on depletion force from the cylindric pipeline is stronger than that from two parallel plates, and the depletion force will be strengthened when the diameter of the cylinder is decreased. In addition, we also find that the depletion interaction is rather affected if the shape change of the pipeline is slightly changed, and the influence on depletion force from the shape change is stronger than that from the size change.     

胶体中排空作用的耦合效应

通过Monte Carlo模拟和接受率方法研究了限制在圆柱形管道中大胶球之间以及大胶球与管壁之间排空作用的耦合效应.研究发现,当两个大胶球靠近时,大胶球之间的排空作用因与大胶球与管道壁之间的排空作用耦合而得到加强,同样当大胶球与管道壁靠近时,大胶球与管道壁之间的排空作用也因与另一大胶球之间排空作用的耦合而得到了加强.此外,研究还发现,随着圆柱形管道直径的减小,胶球之间、胶球与管道壁之间的排空作用的耦合效应是增强的. 关键词： 排空作用的耦合效应 接受率方法 Monte Carlo模拟     

Effects of electrostatic interactions and geometrical confinements on depletion interactions in charged colloidal system

In a charged colloidal system, the influence on depletion interaction between two like-charged macro-ions is studied through Monte Carlo simulation in this paper. The numerical results show that this depletion force is affected by both the electrostatic interactions between charged spheres and charged plates and by the geometrical factor of the two charged plates, and they further indicate that the influence of geometrical confinement on the depletion interaction is larger than that of electrostatic potential.     

厦门组建食药检测中心

<正>为强化食品药品监管工作,厦门将市食品药品监督管理局、市工商行政管理局合并,组建市市场监督管理局,原工商局局长陈海疆担任局长。作为新局的掌门,面对前所未有的机构和职能双重整合,来看看陈海疆打算如何理清千头万绪,打造食药监管新格局。(1)食药生产流通、餐饮管理大统一"组建市场监督管理局,不仅仅是机构的简单组合,它是厦门第一次历史性地实现了多部门食品安全监管职能的有机统一。"在陈海疆看来,此前多部门分散进行食品安全监管,边界多环节多,存在职能分散和职能交叉的情况,容易产     

混合载气高场不对称波形离子迁移谱中He‐N2 比例对挥发性有机物混叠峰分离的影响研究

载气混合是提高高场不对称波形离子迁移谱（FAIMS）离子分离能力的一个重要方法,在生物大分子质谱研究领域已得到广泛应用,但缺乏在环境小分子领域的研究。选取挥发性有机物（VOCs）中芳香烃、醇、烷烃、酸、酮类中的五种物质（邻二甲苯、异丁醇、正己烷、乙酸、丙酮）为研究对象,研究了混合气体中He-N₂比例对VOCs中单体-二聚体离子混叠峰峰位置、分离度及总离子通过率的影响。实验结果表明,随着FAIMS载气中He比例的增加,5种VOCs中单体及二聚体离子峰峰位置发生偏移,且单体峰与二聚体峰偏移程度不同,单体峰偏移量先增加后减少,而二聚体峰峰位置偏移量逐渐增加;随着FAIMS载气中He比例的增加,五种VOCs离子混叠峰的分离度逐渐增加并趋于饱和,邻二甲苯、异丁醇、正己烷、乙酸、丙酮5种样品的混叠峰分离度达到饱和时对应He比例分别是：20%,30%,10%,40%和20%;随着FAIMS载气中He比例的增加,邻二甲苯、异丁醇、正己烷、丙酮的离子信号强度无明显变化,乙酸的离子信号强度下降明显。该研究为提高FAIMS对环境小分子的分离能力提供了一种可行的方法。同时,也验证了高电场下布朗定律在小分子离子应用上的有效性。     

Depletion Interactions in a Cylindric Pipeline with a Small Shape Change

Stressed by external forces, it is possible for a cylindric pipeline to change into an elliptic pipeline. To expose the effect of small shape change of the pipeline on the depletion interactions, both the depletion potentials and depletion forces in the hard sphere systems confined by a cylindric pipeline or by an elliptic pipeline are studied by Monte Carlo simulations. The numerical results show that the depletion interactions are strongly affected by the small change of the shape of the pipeline in a way. Furthermore, it is also found that the depletion interactions will be strengthened if the short axis of the elliptic pipeline is decreased.     

沿一类变非凸曲线的Hilbert变换的L2有界性(英文)

在u:■→■是一个可测函数,P:■→■是一个实多项式和γ满足一些合适的光滑性和曲率条件的前提下,本文证明了沿变曲线(t,u(x₁)P(γ(t)))的Hilbert变换在L²空间中的有界性.     

单原子Co位点的CO2还原反应路径:局部配位环境的影响

在CO2还原反应(CO2RR)应中,单原子催化剂被认为是很有前途的电催化剂.Co-N4活性位点因其优异的CO选择性和活性而受到广泛关注.然而,Co位点的局部配位环境与CO2RR途径之间的相关性尚不明确.本文采用密度泛函理论(DFT)计算,研究了含1,10-菲咯啉基底的N4-大环配体(Co-N4-CPY)负载的CoN4位...